Lug nut torque & warped rotors
Guest
Posts: n/a
Re: Lug nut torque & warped rotors
Your explanation is clear, but difficult to accept.
"Spdloader" <askforit@nospam.triad.rr.com> wrote in message
news:rlhwf.4160$Kp.3269@southeast.rr.com...
> The rotors on your GC are made from two parts, the rotor, and the "hat".
> The hat is the part of the rotor that the wheel studs go through and your
> wheels bolt to. Further, the hat of the rotor rests flat against the wheel
> hub assembly, and you'll not warp that with 250ft. lbs of torque, much
> less the 125 you specified finding. The hat uses a different type of metal
> from the metal in the rotor, specifically to keep lug nut torque from
> being an issue with the rotors.
If the manufacturer changed the rotors to a 2-piece design with dissimilar
metals to guard against problems caused by over/under torquing, why in the
world have they continued to ignore the cross-section thickness of the
rotor? I agree that a thicker rotor (e.g., Brembo) will minimize the
probability of warpage. If Jeep's engineers were genuinely concerned about
the component, they would have re-engineered all known weaknesses, including
warpage. I have to applaud Jeep's technology of rotor assembly. The joint
between the 2 rotor pieces is absolutely indetectable to the naked eye.
> Jeep changed over to this type of rotor during the first series of GC and
> has used them since.
Jeep recognized the advantages of the Akebono caliper in 2002. When were
the rotors changed to a 2-piece model?
> Lug nut torque was not the cause of the warpage on your rotors, hasn't
> been an issue in brake rotor warpage for years, but the general public
> won't let go of the idea.
If that's true, why does Jeep provide a recommended torque range for lug
nuts? Service procedures would be simpler for everyone if the
manufacturer's specification was "85 lbs/ft minimum, user selects maximum".
> The tire installer is not to blame.
You say that random torquing wasn't a contributing factor, so that makes the
tire installer's methods sound? Hell, even the tire busters at Costco use a
torque wrench. If it didn't matter, would Costco bother?
> The rotors being too thin to start with, along with driving habits, stop
> and go or city driving, and overdriving the brakes (driving too fast,
> stopping at the last moment) are the most often the cause of brake
> pulsations, like it or not.
Not in this case. The Jeep is babied. Driving habits are excellent. A
Ford Thunderbird we owned previously (which was notoriously known for rotor
warpage) didn't exhibit any brake problems in 40,000 miles, likely because
of proper driving habits.
> The variations in lug nut torque are not out of line in the real world,
> rust, contamination, imperfect threads, grease, and dirt all affect the
> torque of the lug nuts. In perfect, laboratory conditions, with perfectly
> clean studs and nuts, lightly oiled, and a perfectly calibrated torque
> wrench, you might get 'em close, but that's not the real world.
I guess I'm pickier than most, because I refuse to use an impact wrench on
the lug nuts of any of my vehicles. Interestingly, the Jeep is the only
vehicle I've owned that needed rotor replacement before it needed a brake
job.
> By the way, with aluminum or magnesium wheels, lug nuts should be
> retorqued after driving 50 to 100 miles. ALWAYS.
You're right about that one. I learned that back in the 70s, when I worked
for Chrysler. I still have the same Snap-On Torqometer that I used back
then to torque lug nuts, including vehicles with left-handed threads on the
left side.
> Spdloader
>
>
> "klutz" <klutz@klutzville.net> wrote in message
> news:Azdwf.8592$V.4423@fed1read04...
>> My wife's 2003 Grand Cherokee fell victim to warped rotors, but after
>> completing the repairs, I'm surmising that her driving style didn't cause
>> the problem. While removing the lug nuts with a breaker bar, I felt a
>> disparity in the effort required to loosen them. Hmmm. That can't be
>> good. I wondered what the torque was on the other wheel, so I used a
>> torque wrench to loosen the lugs. Torque varied from 80 to 125 lb/ft on
>> the R/F wheel! Just for safety's sake, I checked the rear wheels. Same
>> sad shape. Torque was all over the map. Moral of the story - when the
>> dealer is doing warranty work (power window) and asks if you want your
>> tires rotated - tell 'em "No, thanks" - unless you can oversee the job.
>> Incidentally, the old rotors and pads had 29,000 miles and wore evenly,
>> with no glazing or hot spots. The pads have 5/16 of friction material
>> left. My money says that the dealer's tire-jockey has caused me (and
>> likely many others) to suffer from warped rotors. Intentionally,
>> perhaps? Hard to prove. Word to the wise - the 2003 WJ has rotors made
>> of soft cast iron. Inattention to wheel torque can destroy them in a
>> heartbeat.
>>
>
>
"Spdloader" <askforit@nospam.triad.rr.com> wrote in message
news:rlhwf.4160$Kp.3269@southeast.rr.com...
> The rotors on your GC are made from two parts, the rotor, and the "hat".
> The hat is the part of the rotor that the wheel studs go through and your
> wheels bolt to. Further, the hat of the rotor rests flat against the wheel
> hub assembly, and you'll not warp that with 250ft. lbs of torque, much
> less the 125 you specified finding. The hat uses a different type of metal
> from the metal in the rotor, specifically to keep lug nut torque from
> being an issue with the rotors.
If the manufacturer changed the rotors to a 2-piece design with dissimilar
metals to guard against problems caused by over/under torquing, why in the
world have they continued to ignore the cross-section thickness of the
rotor? I agree that a thicker rotor (e.g., Brembo) will minimize the
probability of warpage. If Jeep's engineers were genuinely concerned about
the component, they would have re-engineered all known weaknesses, including
warpage. I have to applaud Jeep's technology of rotor assembly. The joint
between the 2 rotor pieces is absolutely indetectable to the naked eye.
> Jeep changed over to this type of rotor during the first series of GC and
> has used them since.
Jeep recognized the advantages of the Akebono caliper in 2002. When were
the rotors changed to a 2-piece model?
> Lug nut torque was not the cause of the warpage on your rotors, hasn't
> been an issue in brake rotor warpage for years, but the general public
> won't let go of the idea.
If that's true, why does Jeep provide a recommended torque range for lug
nuts? Service procedures would be simpler for everyone if the
manufacturer's specification was "85 lbs/ft minimum, user selects maximum".
> The tire installer is not to blame.
You say that random torquing wasn't a contributing factor, so that makes the
tire installer's methods sound? Hell, even the tire busters at Costco use a
torque wrench. If it didn't matter, would Costco bother?
> The rotors being too thin to start with, along with driving habits, stop
> and go or city driving, and overdriving the brakes (driving too fast,
> stopping at the last moment) are the most often the cause of brake
> pulsations, like it or not.
Not in this case. The Jeep is babied. Driving habits are excellent. A
Ford Thunderbird we owned previously (which was notoriously known for rotor
warpage) didn't exhibit any brake problems in 40,000 miles, likely because
of proper driving habits.
> The variations in lug nut torque are not out of line in the real world,
> rust, contamination, imperfect threads, grease, and dirt all affect the
> torque of the lug nuts. In perfect, laboratory conditions, with perfectly
> clean studs and nuts, lightly oiled, and a perfectly calibrated torque
> wrench, you might get 'em close, but that's not the real world.
I guess I'm pickier than most, because I refuse to use an impact wrench on
the lug nuts of any of my vehicles. Interestingly, the Jeep is the only
vehicle I've owned that needed rotor replacement before it needed a brake
job.
> By the way, with aluminum or magnesium wheels, lug nuts should be
> retorqued after driving 50 to 100 miles. ALWAYS.
You're right about that one. I learned that back in the 70s, when I worked
for Chrysler. I still have the same Snap-On Torqometer that I used back
then to torque lug nuts, including vehicles with left-handed threads on the
left side.
> Spdloader
>
>
> "klutz" <klutz@klutzville.net> wrote in message
> news:Azdwf.8592$V.4423@fed1read04...
>> My wife's 2003 Grand Cherokee fell victim to warped rotors, but after
>> completing the repairs, I'm surmising that her driving style didn't cause
>> the problem. While removing the lug nuts with a breaker bar, I felt a
>> disparity in the effort required to loosen them. Hmmm. That can't be
>> good. I wondered what the torque was on the other wheel, so I used a
>> torque wrench to loosen the lugs. Torque varied from 80 to 125 lb/ft on
>> the R/F wheel! Just for safety's sake, I checked the rear wheels. Same
>> sad shape. Torque was all over the map. Moral of the story - when the
>> dealer is doing warranty work (power window) and asks if you want your
>> tires rotated - tell 'em "No, thanks" - unless you can oversee the job.
>> Incidentally, the old rotors and pads had 29,000 miles and wore evenly,
>> with no glazing or hot spots. The pads have 5/16 of friction material
>> left. My money says that the dealer's tire-jockey has caused me (and
>> likely many others) to suffer from warped rotors. Intentionally,
>> perhaps? Hard to prove. Word to the wise - the 2003 WJ has rotors made
>> of soft cast iron. Inattention to wheel torque can destroy them in a
>> heartbeat.
>>
>
>
Guest
Posts: n/a
Re: Lug nut torque & warped rotors
Your explanation is clear, but difficult to accept.
"Spdloader" <askforit@nospam.triad.rr.com> wrote in message
news:rlhwf.4160$Kp.3269@southeast.rr.com...
> The rotors on your GC are made from two parts, the rotor, and the "hat".
> The hat is the part of the rotor that the wheel studs go through and your
> wheels bolt to. Further, the hat of the rotor rests flat against the wheel
> hub assembly, and you'll not warp that with 250ft. lbs of torque, much
> less the 125 you specified finding. The hat uses a different type of metal
> from the metal in the rotor, specifically to keep lug nut torque from
> being an issue with the rotors.
If the manufacturer changed the rotors to a 2-piece design with dissimilar
metals to guard against problems caused by over/under torquing, why in the
world have they continued to ignore the cross-section thickness of the
rotor? I agree that a thicker rotor (e.g., Brembo) will minimize the
probability of warpage. If Jeep's engineers were genuinely concerned about
the component, they would have re-engineered all known weaknesses, including
warpage. I have to applaud Jeep's technology of rotor assembly. The joint
between the 2 rotor pieces is absolutely indetectable to the naked eye.
> Jeep changed over to this type of rotor during the first series of GC and
> has used them since.
Jeep recognized the advantages of the Akebono caliper in 2002. When were
the rotors changed to a 2-piece model?
> Lug nut torque was not the cause of the warpage on your rotors, hasn't
> been an issue in brake rotor warpage for years, but the general public
> won't let go of the idea.
If that's true, why does Jeep provide a recommended torque range for lug
nuts? Service procedures would be simpler for everyone if the
manufacturer's specification was "85 lbs/ft minimum, user selects maximum".
> The tire installer is not to blame.
You say that random torquing wasn't a contributing factor, so that makes the
tire installer's methods sound? Hell, even the tire busters at Costco use a
torque wrench. If it didn't matter, would Costco bother?
> The rotors being too thin to start with, along with driving habits, stop
> and go or city driving, and overdriving the brakes (driving too fast,
> stopping at the last moment) are the most often the cause of brake
> pulsations, like it or not.
Not in this case. The Jeep is babied. Driving habits are excellent. A
Ford Thunderbird we owned previously (which was notoriously known for rotor
warpage) didn't exhibit any brake problems in 40,000 miles, likely because
of proper driving habits.
> The variations in lug nut torque are not out of line in the real world,
> rust, contamination, imperfect threads, grease, and dirt all affect the
> torque of the lug nuts. In perfect, laboratory conditions, with perfectly
> clean studs and nuts, lightly oiled, and a perfectly calibrated torque
> wrench, you might get 'em close, but that's not the real world.
I guess I'm pickier than most, because I refuse to use an impact wrench on
the lug nuts of any of my vehicles. Interestingly, the Jeep is the only
vehicle I've owned that needed rotor replacement before it needed a brake
job.
> By the way, with aluminum or magnesium wheels, lug nuts should be
> retorqued after driving 50 to 100 miles. ALWAYS.
You're right about that one. I learned that back in the 70s, when I worked
for Chrysler. I still have the same Snap-On Torqometer that I used back
then to torque lug nuts, including vehicles with left-handed threads on the
left side.
> Spdloader
>
>
> "klutz" <klutz@klutzville.net> wrote in message
> news:Azdwf.8592$V.4423@fed1read04...
>> My wife's 2003 Grand Cherokee fell victim to warped rotors, but after
>> completing the repairs, I'm surmising that her driving style didn't cause
>> the problem. While removing the lug nuts with a breaker bar, I felt a
>> disparity in the effort required to loosen them. Hmmm. That can't be
>> good. I wondered what the torque was on the other wheel, so I used a
>> torque wrench to loosen the lugs. Torque varied from 80 to 125 lb/ft on
>> the R/F wheel! Just for safety's sake, I checked the rear wheels. Same
>> sad shape. Torque was all over the map. Moral of the story - when the
>> dealer is doing warranty work (power window) and asks if you want your
>> tires rotated - tell 'em "No, thanks" - unless you can oversee the job.
>> Incidentally, the old rotors and pads had 29,000 miles and wore evenly,
>> with no glazing or hot spots. The pads have 5/16 of friction material
>> left. My money says that the dealer's tire-jockey has caused me (and
>> likely many others) to suffer from warped rotors. Intentionally,
>> perhaps? Hard to prove. Word to the wise - the 2003 WJ has rotors made
>> of soft cast iron. Inattention to wheel torque can destroy them in a
>> heartbeat.
>>
>
>
"Spdloader" <askforit@nospam.triad.rr.com> wrote in message
news:rlhwf.4160$Kp.3269@southeast.rr.com...
> The rotors on your GC are made from two parts, the rotor, and the "hat".
> The hat is the part of the rotor that the wheel studs go through and your
> wheels bolt to. Further, the hat of the rotor rests flat against the wheel
> hub assembly, and you'll not warp that with 250ft. lbs of torque, much
> less the 125 you specified finding. The hat uses a different type of metal
> from the metal in the rotor, specifically to keep lug nut torque from
> being an issue with the rotors.
If the manufacturer changed the rotors to a 2-piece design with dissimilar
metals to guard against problems caused by over/under torquing, why in the
world have they continued to ignore the cross-section thickness of the
rotor? I agree that a thicker rotor (e.g., Brembo) will minimize the
probability of warpage. If Jeep's engineers were genuinely concerned about
the component, they would have re-engineered all known weaknesses, including
warpage. I have to applaud Jeep's technology of rotor assembly. The joint
between the 2 rotor pieces is absolutely indetectable to the naked eye.
> Jeep changed over to this type of rotor during the first series of GC and
> has used them since.
Jeep recognized the advantages of the Akebono caliper in 2002. When were
the rotors changed to a 2-piece model?
> Lug nut torque was not the cause of the warpage on your rotors, hasn't
> been an issue in brake rotor warpage for years, but the general public
> won't let go of the idea.
If that's true, why does Jeep provide a recommended torque range for lug
nuts? Service procedures would be simpler for everyone if the
manufacturer's specification was "85 lbs/ft minimum, user selects maximum".
> The tire installer is not to blame.
You say that random torquing wasn't a contributing factor, so that makes the
tire installer's methods sound? Hell, even the tire busters at Costco use a
torque wrench. If it didn't matter, would Costco bother?
> The rotors being too thin to start with, along with driving habits, stop
> and go or city driving, and overdriving the brakes (driving too fast,
> stopping at the last moment) are the most often the cause of brake
> pulsations, like it or not.
Not in this case. The Jeep is babied. Driving habits are excellent. A
Ford Thunderbird we owned previously (which was notoriously known for rotor
warpage) didn't exhibit any brake problems in 40,000 miles, likely because
of proper driving habits.
> The variations in lug nut torque are not out of line in the real world,
> rust, contamination, imperfect threads, grease, and dirt all affect the
> torque of the lug nuts. In perfect, laboratory conditions, with perfectly
> clean studs and nuts, lightly oiled, and a perfectly calibrated torque
> wrench, you might get 'em close, but that's not the real world.
I guess I'm pickier than most, because I refuse to use an impact wrench on
the lug nuts of any of my vehicles. Interestingly, the Jeep is the only
vehicle I've owned that needed rotor replacement before it needed a brake
job.
> By the way, with aluminum or magnesium wheels, lug nuts should be
> retorqued after driving 50 to 100 miles. ALWAYS.
You're right about that one. I learned that back in the 70s, when I worked
for Chrysler. I still have the same Snap-On Torqometer that I used back
then to torque lug nuts, including vehicles with left-handed threads on the
left side.
> Spdloader
>
>
> "klutz" <klutz@klutzville.net> wrote in message
> news:Azdwf.8592$V.4423@fed1read04...
>> My wife's 2003 Grand Cherokee fell victim to warped rotors, but after
>> completing the repairs, I'm surmising that her driving style didn't cause
>> the problem. While removing the lug nuts with a breaker bar, I felt a
>> disparity in the effort required to loosen them. Hmmm. That can't be
>> good. I wondered what the torque was on the other wheel, so I used a
>> torque wrench to loosen the lugs. Torque varied from 80 to 125 lb/ft on
>> the R/F wheel! Just for safety's sake, I checked the rear wheels. Same
>> sad shape. Torque was all over the map. Moral of the story - when the
>> dealer is doing warranty work (power window) and asks if you want your
>> tires rotated - tell 'em "No, thanks" - unless you can oversee the job.
>> Incidentally, the old rotors and pads had 29,000 miles and wore evenly,
>> with no glazing or hot spots. The pads have 5/16 of friction material
>> left. My money says that the dealer's tire-jockey has caused me (and
>> likely many others) to suffer from warped rotors. Intentionally,
>> perhaps? Hard to prove. Word to the wise - the 2003 WJ has rotors made
>> of soft cast iron. Inattention to wheel torque can destroy them in a
>> heartbeat.
>>
>
>
Guest
Posts: n/a
Re: Lug nut torque & warped rotors
Your explanation is clear, but difficult to accept.
"Spdloader" <askforit@nospam.triad.rr.com> wrote in message
news:rlhwf.4160$Kp.3269@southeast.rr.com...
> The rotors on your GC are made from two parts, the rotor, and the "hat".
> The hat is the part of the rotor that the wheel studs go through and your
> wheels bolt to. Further, the hat of the rotor rests flat against the wheel
> hub assembly, and you'll not warp that with 250ft. lbs of torque, much
> less the 125 you specified finding. The hat uses a different type of metal
> from the metal in the rotor, specifically to keep lug nut torque from
> being an issue with the rotors.
If the manufacturer changed the rotors to a 2-piece design with dissimilar
metals to guard against problems caused by over/under torquing, why in the
world have they continued to ignore the cross-section thickness of the
rotor? I agree that a thicker rotor (e.g., Brembo) will minimize the
probability of warpage. If Jeep's engineers were genuinely concerned about
the component, they would have re-engineered all known weaknesses, including
warpage. I have to applaud Jeep's technology of rotor assembly. The joint
between the 2 rotor pieces is absolutely indetectable to the naked eye.
> Jeep changed over to this type of rotor during the first series of GC and
> has used them since.
Jeep recognized the advantages of the Akebono caliper in 2002. When were
the rotors changed to a 2-piece model?
> Lug nut torque was not the cause of the warpage on your rotors, hasn't
> been an issue in brake rotor warpage for years, but the general public
> won't let go of the idea.
If that's true, why does Jeep provide a recommended torque range for lug
nuts? Service procedures would be simpler for everyone if the
manufacturer's specification was "85 lbs/ft minimum, user selects maximum".
> The tire installer is not to blame.
You say that random torquing wasn't a contributing factor, so that makes the
tire installer's methods sound? Hell, even the tire busters at Costco use a
torque wrench. If it didn't matter, would Costco bother?
> The rotors being too thin to start with, along with driving habits, stop
> and go or city driving, and overdriving the brakes (driving too fast,
> stopping at the last moment) are the most often the cause of brake
> pulsations, like it or not.
Not in this case. The Jeep is babied. Driving habits are excellent. A
Ford Thunderbird we owned previously (which was notoriously known for rotor
warpage) didn't exhibit any brake problems in 40,000 miles, likely because
of proper driving habits.
> The variations in lug nut torque are not out of line in the real world,
> rust, contamination, imperfect threads, grease, and dirt all affect the
> torque of the lug nuts. In perfect, laboratory conditions, with perfectly
> clean studs and nuts, lightly oiled, and a perfectly calibrated torque
> wrench, you might get 'em close, but that's not the real world.
I guess I'm pickier than most, because I refuse to use an impact wrench on
the lug nuts of any of my vehicles. Interestingly, the Jeep is the only
vehicle I've owned that needed rotor replacement before it needed a brake
job.
> By the way, with aluminum or magnesium wheels, lug nuts should be
> retorqued after driving 50 to 100 miles. ALWAYS.
You're right about that one. I learned that back in the 70s, when I worked
for Chrysler. I still have the same Snap-On Torqometer that I used back
then to torque lug nuts, including vehicles with left-handed threads on the
left side.
> Spdloader
>
>
> "klutz" <klutz@klutzville.net> wrote in message
> news:Azdwf.8592$V.4423@fed1read04...
>> My wife's 2003 Grand Cherokee fell victim to warped rotors, but after
>> completing the repairs, I'm surmising that her driving style didn't cause
>> the problem. While removing the lug nuts with a breaker bar, I felt a
>> disparity in the effort required to loosen them. Hmmm. That can't be
>> good. I wondered what the torque was on the other wheel, so I used a
>> torque wrench to loosen the lugs. Torque varied from 80 to 125 lb/ft on
>> the R/F wheel! Just for safety's sake, I checked the rear wheels. Same
>> sad shape. Torque was all over the map. Moral of the story - when the
>> dealer is doing warranty work (power window) and asks if you want your
>> tires rotated - tell 'em "No, thanks" - unless you can oversee the job.
>> Incidentally, the old rotors and pads had 29,000 miles and wore evenly,
>> with no glazing or hot spots. The pads have 5/16 of friction material
>> left. My money says that the dealer's tire-jockey has caused me (and
>> likely many others) to suffer from warped rotors. Intentionally,
>> perhaps? Hard to prove. Word to the wise - the 2003 WJ has rotors made
>> of soft cast iron. Inattention to wheel torque can destroy them in a
>> heartbeat.
>>
>
>
"Spdloader" <askforit@nospam.triad.rr.com> wrote in message
news:rlhwf.4160$Kp.3269@southeast.rr.com...
> The rotors on your GC are made from two parts, the rotor, and the "hat".
> The hat is the part of the rotor that the wheel studs go through and your
> wheels bolt to. Further, the hat of the rotor rests flat against the wheel
> hub assembly, and you'll not warp that with 250ft. lbs of torque, much
> less the 125 you specified finding. The hat uses a different type of metal
> from the metal in the rotor, specifically to keep lug nut torque from
> being an issue with the rotors.
If the manufacturer changed the rotors to a 2-piece design with dissimilar
metals to guard against problems caused by over/under torquing, why in the
world have they continued to ignore the cross-section thickness of the
rotor? I agree that a thicker rotor (e.g., Brembo) will minimize the
probability of warpage. If Jeep's engineers were genuinely concerned about
the component, they would have re-engineered all known weaknesses, including
warpage. I have to applaud Jeep's technology of rotor assembly. The joint
between the 2 rotor pieces is absolutely indetectable to the naked eye.
> Jeep changed over to this type of rotor during the first series of GC and
> has used them since.
Jeep recognized the advantages of the Akebono caliper in 2002. When were
the rotors changed to a 2-piece model?
> Lug nut torque was not the cause of the warpage on your rotors, hasn't
> been an issue in brake rotor warpage for years, but the general public
> won't let go of the idea.
If that's true, why does Jeep provide a recommended torque range for lug
nuts? Service procedures would be simpler for everyone if the
manufacturer's specification was "85 lbs/ft minimum, user selects maximum".
> The tire installer is not to blame.
You say that random torquing wasn't a contributing factor, so that makes the
tire installer's methods sound? Hell, even the tire busters at Costco use a
torque wrench. If it didn't matter, would Costco bother?
> The rotors being too thin to start with, along with driving habits, stop
> and go or city driving, and overdriving the brakes (driving too fast,
> stopping at the last moment) are the most often the cause of brake
> pulsations, like it or not.
Not in this case. The Jeep is babied. Driving habits are excellent. A
Ford Thunderbird we owned previously (which was notoriously known for rotor
warpage) didn't exhibit any brake problems in 40,000 miles, likely because
of proper driving habits.
> The variations in lug nut torque are not out of line in the real world,
> rust, contamination, imperfect threads, grease, and dirt all affect the
> torque of the lug nuts. In perfect, laboratory conditions, with perfectly
> clean studs and nuts, lightly oiled, and a perfectly calibrated torque
> wrench, you might get 'em close, but that's not the real world.
I guess I'm pickier than most, because I refuse to use an impact wrench on
the lug nuts of any of my vehicles. Interestingly, the Jeep is the only
vehicle I've owned that needed rotor replacement before it needed a brake
job.
> By the way, with aluminum or magnesium wheels, lug nuts should be
> retorqued after driving 50 to 100 miles. ALWAYS.
You're right about that one. I learned that back in the 70s, when I worked
for Chrysler. I still have the same Snap-On Torqometer that I used back
then to torque lug nuts, including vehicles with left-handed threads on the
left side.
> Spdloader
>
>
> "klutz" <klutz@klutzville.net> wrote in message
> news:Azdwf.8592$V.4423@fed1read04...
>> My wife's 2003 Grand Cherokee fell victim to warped rotors, but after
>> completing the repairs, I'm surmising that her driving style didn't cause
>> the problem. While removing the lug nuts with a breaker bar, I felt a
>> disparity in the effort required to loosen them. Hmmm. That can't be
>> good. I wondered what the torque was on the other wheel, so I used a
>> torque wrench to loosen the lugs. Torque varied from 80 to 125 lb/ft on
>> the R/F wheel! Just for safety's sake, I checked the rear wheels. Same
>> sad shape. Torque was all over the map. Moral of the story - when the
>> dealer is doing warranty work (power window) and asks if you want your
>> tires rotated - tell 'em "No, thanks" - unless you can oversee the job.
>> Incidentally, the old rotors and pads had 29,000 miles and wore evenly,
>> with no glazing or hot spots. The pads have 5/16 of friction material
>> left. My money says that the dealer's tire-jockey has caused me (and
>> likely many others) to suffer from warped rotors. Intentionally,
>> perhaps? Hard to prove. Word to the wise - the 2003 WJ has rotors made
>> of soft cast iron. Inattention to wheel torque can destroy them in a
>> heartbeat.
>>
>
>
Guest
Posts: n/a
Re: Lug nut torque & warped rotors
Klutz and Spdloader,
Composite rotors used for several years on Jeeps were not installed by
the factory to lessen rotor warping. They were a cost-reduced and
significantly lightened rotor that warped so easily that Jeep went back
to all-cast rotor. They were so light in weight that they weren't able
to resist warping from both heat and uneven lugnut tightening. Newer
Wranglers and JGCs have all-cast rotors that are far better able to
resist heat and uneven-tightening induced warping.
Jerry
klutz wrote:
> Your explanation is clear, but difficult to accept.
>
> "Spdloader" <askforit@nospam.triad.rr.com> wrote in message
> news:rlhwf.4160$Kp.3269@southeast.rr.com...
>
>>The rotors on your GC are made from two parts, the rotor, and the "hat".
>>The hat is the part of the rotor that the wheel studs go through and your
>>wheels bolt to. Further, the hat of the rotor rests flat against the wheel
>>hub assembly, and you'll not warp that with 250ft. lbs of torque, much
>>less the 125 you specified finding. The hat uses a different type of metal
>>from the metal in the rotor, specifically to keep lug nut torque from
>>being an issue with the rotors.
>
>
> If the manufacturer changed the rotors to a 2-piece design with dissimilar
> metals to guard against problems caused by over/under torquing, why in the
> world have they continued to ignore the cross-section thickness of the
> rotor? I agree that a thicker rotor (e.g., Brembo) will minimize the
> probability of warpage. If Jeep's engineers were genuinely concerned about
> the component, they would have re-engineered all known weaknesses, including
> warpage. I have to applaud Jeep's technology of rotor assembly. The joint
> between the 2 rotor pieces is absolutely indetectable to the naked eye.
>
>
>>Jeep changed over to this type of rotor during the first series of GC and
>>has used them since.
>
>
> Jeep recognized the advantages of the Akebono caliper in 2002. When were
> the rotors changed to a 2-piece model?
>
>
>>Lug nut torque was not the cause of the warpage on your rotors, hasn't
>>been an issue in brake rotor warpage for years, but the general public
>>won't let go of the idea.
>
>
> If that's true, why does Jeep provide a recommended torque range for lug
> nuts? Service procedures would be simpler for everyone if the
> manufacturer's specification was "85 lbs/ft minimum, user selects maximum".
>
>
>>The tire installer is not to blame.
>
>
> You say that random torquing wasn't a contributing factor, so that makes the
> tire installer's methods sound? Hell, even the tire busters at Costco use a
> torque wrench. If it didn't matter, would Costco bother?
>
>
>>The rotors being too thin to start with, along with driving habits, stop
>>and go or city driving, and overdriving the brakes (driving too fast,
>>stopping at the last moment) are the most often the cause of brake
>>pulsations, like it or not.
>
>
> Not in this case. The Jeep is babied. Driving habits are excellent. A
> Ford Thunderbird we owned previously (which was notoriously known for rotor
> warpage) didn't exhibit any brake problems in 40,000 miles, likely because
> of proper driving habits.
>
>
>>The variations in lug nut torque are not out of line in the real world,
>>rust, contamination, imperfect threads, grease, and dirt all affect the
>>torque of the lug nuts. In perfect, laboratory conditions, with perfectly
>>clean studs and nuts, lightly oiled, and a perfectly calibrated torque
>>wrench, you might get 'em close, but that's not the real world.
>
>
> I guess I'm pickier than most, because I refuse to use an impact wrench on
> the lug nuts of any of my vehicles. Interestingly, the Jeep is the only
> vehicle I've owned that needed rotor replacement before it needed a brake
> job.
>
>
>>By the way, with aluminum or magnesium wheels, lug nuts should be
>>retorqued after driving 50 to 100 miles. ALWAYS.
>
>
> You're right about that one. I learned that back in the 70s, when I worked
> for Chrysler. I still have the same Snap-On Torqometer that I used back
> then to torque lug nuts, including vehicles with left-handed threads on the
> left side.
>
>
>>Spdloader
>>
>>
>>"klutz" <klutz@klutzville.net> wrote in message
>>news:Azdwf.8592$V.4423@fed1read04...
>>
>>>My wife's 2003 Grand Cherokee fell victim to warped rotors, but after
>>>completing the repairs, I'm surmising that her driving style didn't cause
>>>the problem. While removing the lug nuts with a breaker bar, I felt a
>>>disparity in the effort required to loosen them. Hmmm. That can't be
>>>good. I wondered what the torque was on the other wheel, so I used a
>>>torque wrench to loosen the lugs. Torque varied from 80 to 125 lb/ft on
>>>the R/F wheel! Just for safety's sake, I checked the rear wheels. Same
>>>sad shape. Torque was all over the map. Moral of the story - when the
>>>dealer is doing warranty work (power window) and asks if you want your
>>>tires rotated - tell 'em "No, thanks" - unless you can oversee the job.
>>>Incidentally, the old rotors and pads had 29,000 miles and wore evenly,
>>>with no glazing or hot spots. The pads have 5/16 of friction material
>>>left. My money says that the dealer's tire-jockey has caused me (and
>>>likely many others) to suffer from warped rotors. Intentionally,
>>>perhaps? Hard to prove. Word to the wise - the 2003 WJ has rotors made
>>>of soft cast iron. Inattention to wheel torque can destroy them in a
>>>heartbeat.
>>>
>>
>>
>
>
--
Jerry Bransford
PP-ASEL N6TAY
See the Geezer Jeep at
http://members.***.net/jerrypb/
Composite rotors used for several years on Jeeps were not installed by
the factory to lessen rotor warping. They were a cost-reduced and
significantly lightened rotor that warped so easily that Jeep went back
to all-cast rotor. They were so light in weight that they weren't able
to resist warping from both heat and uneven lugnut tightening. Newer
Wranglers and JGCs have all-cast rotors that are far better able to
resist heat and uneven-tightening induced warping.
Jerry
klutz wrote:
> Your explanation is clear, but difficult to accept.
>
> "Spdloader" <askforit@nospam.triad.rr.com> wrote in message
> news:rlhwf.4160$Kp.3269@southeast.rr.com...
>
>>The rotors on your GC are made from two parts, the rotor, and the "hat".
>>The hat is the part of the rotor that the wheel studs go through and your
>>wheels bolt to. Further, the hat of the rotor rests flat against the wheel
>>hub assembly, and you'll not warp that with 250ft. lbs of torque, much
>>less the 125 you specified finding. The hat uses a different type of metal
>>from the metal in the rotor, specifically to keep lug nut torque from
>>being an issue with the rotors.
>
>
> If the manufacturer changed the rotors to a 2-piece design with dissimilar
> metals to guard against problems caused by over/under torquing, why in the
> world have they continued to ignore the cross-section thickness of the
> rotor? I agree that a thicker rotor (e.g., Brembo) will minimize the
> probability of warpage. If Jeep's engineers were genuinely concerned about
> the component, they would have re-engineered all known weaknesses, including
> warpage. I have to applaud Jeep's technology of rotor assembly. The joint
> between the 2 rotor pieces is absolutely indetectable to the naked eye.
>
>
>>Jeep changed over to this type of rotor during the first series of GC and
>>has used them since.
>
>
> Jeep recognized the advantages of the Akebono caliper in 2002. When were
> the rotors changed to a 2-piece model?
>
>
>>Lug nut torque was not the cause of the warpage on your rotors, hasn't
>>been an issue in brake rotor warpage for years, but the general public
>>won't let go of the idea.
>
>
> If that's true, why does Jeep provide a recommended torque range for lug
> nuts? Service procedures would be simpler for everyone if the
> manufacturer's specification was "85 lbs/ft minimum, user selects maximum".
>
>
>>The tire installer is not to blame.
>
>
> You say that random torquing wasn't a contributing factor, so that makes the
> tire installer's methods sound? Hell, even the tire busters at Costco use a
> torque wrench. If it didn't matter, would Costco bother?
>
>
>>The rotors being too thin to start with, along with driving habits, stop
>>and go or city driving, and overdriving the brakes (driving too fast,
>>stopping at the last moment) are the most often the cause of brake
>>pulsations, like it or not.
>
>
> Not in this case. The Jeep is babied. Driving habits are excellent. A
> Ford Thunderbird we owned previously (which was notoriously known for rotor
> warpage) didn't exhibit any brake problems in 40,000 miles, likely because
> of proper driving habits.
>
>
>>The variations in lug nut torque are not out of line in the real world,
>>rust, contamination, imperfect threads, grease, and dirt all affect the
>>torque of the lug nuts. In perfect, laboratory conditions, with perfectly
>>clean studs and nuts, lightly oiled, and a perfectly calibrated torque
>>wrench, you might get 'em close, but that's not the real world.
>
>
> I guess I'm pickier than most, because I refuse to use an impact wrench on
> the lug nuts of any of my vehicles. Interestingly, the Jeep is the only
> vehicle I've owned that needed rotor replacement before it needed a brake
> job.
>
>
>>By the way, with aluminum or magnesium wheels, lug nuts should be
>>retorqued after driving 50 to 100 miles. ALWAYS.
>
>
> You're right about that one. I learned that back in the 70s, when I worked
> for Chrysler. I still have the same Snap-On Torqometer that I used back
> then to torque lug nuts, including vehicles with left-handed threads on the
> left side.
>
>
>>Spdloader
>>
>>
>>"klutz" <klutz@klutzville.net> wrote in message
>>news:Azdwf.8592$V.4423@fed1read04...
>>
>>>My wife's 2003 Grand Cherokee fell victim to warped rotors, but after
>>>completing the repairs, I'm surmising that her driving style didn't cause
>>>the problem. While removing the lug nuts with a breaker bar, I felt a
>>>disparity in the effort required to loosen them. Hmmm. That can't be
>>>good. I wondered what the torque was on the other wheel, so I used a
>>>torque wrench to loosen the lugs. Torque varied from 80 to 125 lb/ft on
>>>the R/F wheel! Just for safety's sake, I checked the rear wheels. Same
>>>sad shape. Torque was all over the map. Moral of the story - when the
>>>dealer is doing warranty work (power window) and asks if you want your
>>>tires rotated - tell 'em "No, thanks" - unless you can oversee the job.
>>>Incidentally, the old rotors and pads had 29,000 miles and wore evenly,
>>>with no glazing or hot spots. The pads have 5/16 of friction material
>>>left. My money says that the dealer's tire-jockey has caused me (and
>>>likely many others) to suffer from warped rotors. Intentionally,
>>>perhaps? Hard to prove. Word to the wise - the 2003 WJ has rotors made
>>>of soft cast iron. Inattention to wheel torque can destroy them in a
>>>heartbeat.
>>>
>>
>>
>
>
--
Jerry Bransford
PP-ASEL N6TAY
See the Geezer Jeep at
http://members.***.net/jerrypb/
Guest
Posts: n/a
Re: Lug nut torque & warped rotors
Klutz and Spdloader,
Composite rotors used for several years on Jeeps were not installed by
the factory to lessen rotor warping. They were a cost-reduced and
significantly lightened rotor that warped so easily that Jeep went back
to all-cast rotor. They were so light in weight that they weren't able
to resist warping from both heat and uneven lugnut tightening. Newer
Wranglers and JGCs have all-cast rotors that are far better able to
resist heat and uneven-tightening induced warping.
Jerry
klutz wrote:
> Your explanation is clear, but difficult to accept.
>
> "Spdloader" <askforit@nospam.triad.rr.com> wrote in message
> news:rlhwf.4160$Kp.3269@southeast.rr.com...
>
>>The rotors on your GC are made from two parts, the rotor, and the "hat".
>>The hat is the part of the rotor that the wheel studs go through and your
>>wheels bolt to. Further, the hat of the rotor rests flat against the wheel
>>hub assembly, and you'll not warp that with 250ft. lbs of torque, much
>>less the 125 you specified finding. The hat uses a different type of metal
>>from the metal in the rotor, specifically to keep lug nut torque from
>>being an issue with the rotors.
>
>
> If the manufacturer changed the rotors to a 2-piece design with dissimilar
> metals to guard against problems caused by over/under torquing, why in the
> world have they continued to ignore the cross-section thickness of the
> rotor? I agree that a thicker rotor (e.g., Brembo) will minimize the
> probability of warpage. If Jeep's engineers were genuinely concerned about
> the component, they would have re-engineered all known weaknesses, including
> warpage. I have to applaud Jeep's technology of rotor assembly. The joint
> between the 2 rotor pieces is absolutely indetectable to the naked eye.
>
>
>>Jeep changed over to this type of rotor during the first series of GC and
>>has used them since.
>
>
> Jeep recognized the advantages of the Akebono caliper in 2002. When were
> the rotors changed to a 2-piece model?
>
>
>>Lug nut torque was not the cause of the warpage on your rotors, hasn't
>>been an issue in brake rotor warpage for years, but the general public
>>won't let go of the idea.
>
>
> If that's true, why does Jeep provide a recommended torque range for lug
> nuts? Service procedures would be simpler for everyone if the
> manufacturer's specification was "85 lbs/ft minimum, user selects maximum".
>
>
>>The tire installer is not to blame.
>
>
> You say that random torquing wasn't a contributing factor, so that makes the
> tire installer's methods sound? Hell, even the tire busters at Costco use a
> torque wrench. If it didn't matter, would Costco bother?
>
>
>>The rotors being too thin to start with, along with driving habits, stop
>>and go or city driving, and overdriving the brakes (driving too fast,
>>stopping at the last moment) are the most often the cause of brake
>>pulsations, like it or not.
>
>
> Not in this case. The Jeep is babied. Driving habits are excellent. A
> Ford Thunderbird we owned previously (which was notoriously known for rotor
> warpage) didn't exhibit any brake problems in 40,000 miles, likely because
> of proper driving habits.
>
>
>>The variations in lug nut torque are not out of line in the real world,
>>rust, contamination, imperfect threads, grease, and dirt all affect the
>>torque of the lug nuts. In perfect, laboratory conditions, with perfectly
>>clean studs and nuts, lightly oiled, and a perfectly calibrated torque
>>wrench, you might get 'em close, but that's not the real world.
>
>
> I guess I'm pickier than most, because I refuse to use an impact wrench on
> the lug nuts of any of my vehicles. Interestingly, the Jeep is the only
> vehicle I've owned that needed rotor replacement before it needed a brake
> job.
>
>
>>By the way, with aluminum or magnesium wheels, lug nuts should be
>>retorqued after driving 50 to 100 miles. ALWAYS.
>
>
> You're right about that one. I learned that back in the 70s, when I worked
> for Chrysler. I still have the same Snap-On Torqometer that I used back
> then to torque lug nuts, including vehicles with left-handed threads on the
> left side.
>
>
>>Spdloader
>>
>>
>>"klutz" <klutz@klutzville.net> wrote in message
>>news:Azdwf.8592$V.4423@fed1read04...
>>
>>>My wife's 2003 Grand Cherokee fell victim to warped rotors, but after
>>>completing the repairs, I'm surmising that her driving style didn't cause
>>>the problem. While removing the lug nuts with a breaker bar, I felt a
>>>disparity in the effort required to loosen them. Hmmm. That can't be
>>>good. I wondered what the torque was on the other wheel, so I used a
>>>torque wrench to loosen the lugs. Torque varied from 80 to 125 lb/ft on
>>>the R/F wheel! Just for safety's sake, I checked the rear wheels. Same
>>>sad shape. Torque was all over the map. Moral of the story - when the
>>>dealer is doing warranty work (power window) and asks if you want your
>>>tires rotated - tell 'em "No, thanks" - unless you can oversee the job.
>>>Incidentally, the old rotors and pads had 29,000 miles and wore evenly,
>>>with no glazing or hot spots. The pads have 5/16 of friction material
>>>left. My money says that the dealer's tire-jockey has caused me (and
>>>likely many others) to suffer from warped rotors. Intentionally,
>>>perhaps? Hard to prove. Word to the wise - the 2003 WJ has rotors made
>>>of soft cast iron. Inattention to wheel torque can destroy them in a
>>>heartbeat.
>>>
>>
>>
>
>
--
Jerry Bransford
PP-ASEL N6TAY
See the Geezer Jeep at
http://members.***.net/jerrypb/
Composite rotors used for several years on Jeeps were not installed by
the factory to lessen rotor warping. They were a cost-reduced and
significantly lightened rotor that warped so easily that Jeep went back
to all-cast rotor. They were so light in weight that they weren't able
to resist warping from both heat and uneven lugnut tightening. Newer
Wranglers and JGCs have all-cast rotors that are far better able to
resist heat and uneven-tightening induced warping.
Jerry
klutz wrote:
> Your explanation is clear, but difficult to accept.
>
> "Spdloader" <askforit@nospam.triad.rr.com> wrote in message
> news:rlhwf.4160$Kp.3269@southeast.rr.com...
>
>>The rotors on your GC are made from two parts, the rotor, and the "hat".
>>The hat is the part of the rotor that the wheel studs go through and your
>>wheels bolt to. Further, the hat of the rotor rests flat against the wheel
>>hub assembly, and you'll not warp that with 250ft. lbs of torque, much
>>less the 125 you specified finding. The hat uses a different type of metal
>>from the metal in the rotor, specifically to keep lug nut torque from
>>being an issue with the rotors.
>
>
> If the manufacturer changed the rotors to a 2-piece design with dissimilar
> metals to guard against problems caused by over/under torquing, why in the
> world have they continued to ignore the cross-section thickness of the
> rotor? I agree that a thicker rotor (e.g., Brembo) will minimize the
> probability of warpage. If Jeep's engineers were genuinely concerned about
> the component, they would have re-engineered all known weaknesses, including
> warpage. I have to applaud Jeep's technology of rotor assembly. The joint
> between the 2 rotor pieces is absolutely indetectable to the naked eye.
>
>
>>Jeep changed over to this type of rotor during the first series of GC and
>>has used them since.
>
>
> Jeep recognized the advantages of the Akebono caliper in 2002. When were
> the rotors changed to a 2-piece model?
>
>
>>Lug nut torque was not the cause of the warpage on your rotors, hasn't
>>been an issue in brake rotor warpage for years, but the general public
>>won't let go of the idea.
>
>
> If that's true, why does Jeep provide a recommended torque range for lug
> nuts? Service procedures would be simpler for everyone if the
> manufacturer's specification was "85 lbs/ft minimum, user selects maximum".
>
>
>>The tire installer is not to blame.
>
>
> You say that random torquing wasn't a contributing factor, so that makes the
> tire installer's methods sound? Hell, even the tire busters at Costco use a
> torque wrench. If it didn't matter, would Costco bother?
>
>
>>The rotors being too thin to start with, along with driving habits, stop
>>and go or city driving, and overdriving the brakes (driving too fast,
>>stopping at the last moment) are the most often the cause of brake
>>pulsations, like it or not.
>
>
> Not in this case. The Jeep is babied. Driving habits are excellent. A
> Ford Thunderbird we owned previously (which was notoriously known for rotor
> warpage) didn't exhibit any brake problems in 40,000 miles, likely because
> of proper driving habits.
>
>
>>The variations in lug nut torque are not out of line in the real world,
>>rust, contamination, imperfect threads, grease, and dirt all affect the
>>torque of the lug nuts. In perfect, laboratory conditions, with perfectly
>>clean studs and nuts, lightly oiled, and a perfectly calibrated torque
>>wrench, you might get 'em close, but that's not the real world.
>
>
> I guess I'm pickier than most, because I refuse to use an impact wrench on
> the lug nuts of any of my vehicles. Interestingly, the Jeep is the only
> vehicle I've owned that needed rotor replacement before it needed a brake
> job.
>
>
>>By the way, with aluminum or magnesium wheels, lug nuts should be
>>retorqued after driving 50 to 100 miles. ALWAYS.
>
>
> You're right about that one. I learned that back in the 70s, when I worked
> for Chrysler. I still have the same Snap-On Torqometer that I used back
> then to torque lug nuts, including vehicles with left-handed threads on the
> left side.
>
>
>>Spdloader
>>
>>
>>"klutz" <klutz@klutzville.net> wrote in message
>>news:Azdwf.8592$V.4423@fed1read04...
>>
>>>My wife's 2003 Grand Cherokee fell victim to warped rotors, but after
>>>completing the repairs, I'm surmising that her driving style didn't cause
>>>the problem. While removing the lug nuts with a breaker bar, I felt a
>>>disparity in the effort required to loosen them. Hmmm. That can't be
>>>good. I wondered what the torque was on the other wheel, so I used a
>>>torque wrench to loosen the lugs. Torque varied from 80 to 125 lb/ft on
>>>the R/F wheel! Just for safety's sake, I checked the rear wheels. Same
>>>sad shape. Torque was all over the map. Moral of the story - when the
>>>dealer is doing warranty work (power window) and asks if you want your
>>>tires rotated - tell 'em "No, thanks" - unless you can oversee the job.
>>>Incidentally, the old rotors and pads had 29,000 miles and wore evenly,
>>>with no glazing or hot spots. The pads have 5/16 of friction material
>>>left. My money says that the dealer's tire-jockey has caused me (and
>>>likely many others) to suffer from warped rotors. Intentionally,
>>>perhaps? Hard to prove. Word to the wise - the 2003 WJ has rotors made
>>>of soft cast iron. Inattention to wheel torque can destroy them in a
>>>heartbeat.
>>>
>>
>>
>
>
--
Jerry Bransford
PP-ASEL N6TAY
See the Geezer Jeep at
http://members.***.net/jerrypb/
Guest
Posts: n/a
Re: Lug nut torque & warped rotors
Klutz and Spdloader,
Composite rotors used for several years on Jeeps were not installed by
the factory to lessen rotor warping. They were a cost-reduced and
significantly lightened rotor that warped so easily that Jeep went back
to all-cast rotor. They were so light in weight that they weren't able
to resist warping from both heat and uneven lugnut tightening. Newer
Wranglers and JGCs have all-cast rotors that are far better able to
resist heat and uneven-tightening induced warping.
Jerry
klutz wrote:
> Your explanation is clear, but difficult to accept.
>
> "Spdloader" <askforit@nospam.triad.rr.com> wrote in message
> news:rlhwf.4160$Kp.3269@southeast.rr.com...
>
>>The rotors on your GC are made from two parts, the rotor, and the "hat".
>>The hat is the part of the rotor that the wheel studs go through and your
>>wheels bolt to. Further, the hat of the rotor rests flat against the wheel
>>hub assembly, and you'll not warp that with 250ft. lbs of torque, much
>>less the 125 you specified finding. The hat uses a different type of metal
>>from the metal in the rotor, specifically to keep lug nut torque from
>>being an issue with the rotors.
>
>
> If the manufacturer changed the rotors to a 2-piece design with dissimilar
> metals to guard against problems caused by over/under torquing, why in the
> world have they continued to ignore the cross-section thickness of the
> rotor? I agree that a thicker rotor (e.g., Brembo) will minimize the
> probability of warpage. If Jeep's engineers were genuinely concerned about
> the component, they would have re-engineered all known weaknesses, including
> warpage. I have to applaud Jeep's technology of rotor assembly. The joint
> between the 2 rotor pieces is absolutely indetectable to the naked eye.
>
>
>>Jeep changed over to this type of rotor during the first series of GC and
>>has used them since.
>
>
> Jeep recognized the advantages of the Akebono caliper in 2002. When were
> the rotors changed to a 2-piece model?
>
>
>>Lug nut torque was not the cause of the warpage on your rotors, hasn't
>>been an issue in brake rotor warpage for years, but the general public
>>won't let go of the idea.
>
>
> If that's true, why does Jeep provide a recommended torque range for lug
> nuts? Service procedures would be simpler for everyone if the
> manufacturer's specification was "85 lbs/ft minimum, user selects maximum".
>
>
>>The tire installer is not to blame.
>
>
> You say that random torquing wasn't a contributing factor, so that makes the
> tire installer's methods sound? Hell, even the tire busters at Costco use a
> torque wrench. If it didn't matter, would Costco bother?
>
>
>>The rotors being too thin to start with, along with driving habits, stop
>>and go or city driving, and overdriving the brakes (driving too fast,
>>stopping at the last moment) are the most often the cause of brake
>>pulsations, like it or not.
>
>
> Not in this case. The Jeep is babied. Driving habits are excellent. A
> Ford Thunderbird we owned previously (which was notoriously known for rotor
> warpage) didn't exhibit any brake problems in 40,000 miles, likely because
> of proper driving habits.
>
>
>>The variations in lug nut torque are not out of line in the real world,
>>rust, contamination, imperfect threads, grease, and dirt all affect the
>>torque of the lug nuts. In perfect, laboratory conditions, with perfectly
>>clean studs and nuts, lightly oiled, and a perfectly calibrated torque
>>wrench, you might get 'em close, but that's not the real world.
>
>
> I guess I'm pickier than most, because I refuse to use an impact wrench on
> the lug nuts of any of my vehicles. Interestingly, the Jeep is the only
> vehicle I've owned that needed rotor replacement before it needed a brake
> job.
>
>
>>By the way, with aluminum or magnesium wheels, lug nuts should be
>>retorqued after driving 50 to 100 miles. ALWAYS.
>
>
> You're right about that one. I learned that back in the 70s, when I worked
> for Chrysler. I still have the same Snap-On Torqometer that I used back
> then to torque lug nuts, including vehicles with left-handed threads on the
> left side.
>
>
>>Spdloader
>>
>>
>>"klutz" <klutz@klutzville.net> wrote in message
>>news:Azdwf.8592$V.4423@fed1read04...
>>
>>>My wife's 2003 Grand Cherokee fell victim to warped rotors, but after
>>>completing the repairs, I'm surmising that her driving style didn't cause
>>>the problem. While removing the lug nuts with a breaker bar, I felt a
>>>disparity in the effort required to loosen them. Hmmm. That can't be
>>>good. I wondered what the torque was on the other wheel, so I used a
>>>torque wrench to loosen the lugs. Torque varied from 80 to 125 lb/ft on
>>>the R/F wheel! Just for safety's sake, I checked the rear wheels. Same
>>>sad shape. Torque was all over the map. Moral of the story - when the
>>>dealer is doing warranty work (power window) and asks if you want your
>>>tires rotated - tell 'em "No, thanks" - unless you can oversee the job.
>>>Incidentally, the old rotors and pads had 29,000 miles and wore evenly,
>>>with no glazing or hot spots. The pads have 5/16 of friction material
>>>left. My money says that the dealer's tire-jockey has caused me (and
>>>likely many others) to suffer from warped rotors. Intentionally,
>>>perhaps? Hard to prove. Word to the wise - the 2003 WJ has rotors made
>>>of soft cast iron. Inattention to wheel torque can destroy them in a
>>>heartbeat.
>>>
>>
>>
>
>
--
Jerry Bransford
PP-ASEL N6TAY
See the Geezer Jeep at
http://members.***.net/jerrypb/
Composite rotors used for several years on Jeeps were not installed by
the factory to lessen rotor warping. They were a cost-reduced and
significantly lightened rotor that warped so easily that Jeep went back
to all-cast rotor. They were so light in weight that they weren't able
to resist warping from both heat and uneven lugnut tightening. Newer
Wranglers and JGCs have all-cast rotors that are far better able to
resist heat and uneven-tightening induced warping.
Jerry
klutz wrote:
> Your explanation is clear, but difficult to accept.
>
> "Spdloader" <askforit@nospam.triad.rr.com> wrote in message
> news:rlhwf.4160$Kp.3269@southeast.rr.com...
>
>>The rotors on your GC are made from two parts, the rotor, and the "hat".
>>The hat is the part of the rotor that the wheel studs go through and your
>>wheels bolt to. Further, the hat of the rotor rests flat against the wheel
>>hub assembly, and you'll not warp that with 250ft. lbs of torque, much
>>less the 125 you specified finding. The hat uses a different type of metal
>>from the metal in the rotor, specifically to keep lug nut torque from
>>being an issue with the rotors.
>
>
> If the manufacturer changed the rotors to a 2-piece design with dissimilar
> metals to guard against problems caused by over/under torquing, why in the
> world have they continued to ignore the cross-section thickness of the
> rotor? I agree that a thicker rotor (e.g., Brembo) will minimize the
> probability of warpage. If Jeep's engineers were genuinely concerned about
> the component, they would have re-engineered all known weaknesses, including
> warpage. I have to applaud Jeep's technology of rotor assembly. The joint
> between the 2 rotor pieces is absolutely indetectable to the naked eye.
>
>
>>Jeep changed over to this type of rotor during the first series of GC and
>>has used them since.
>
>
> Jeep recognized the advantages of the Akebono caliper in 2002. When were
> the rotors changed to a 2-piece model?
>
>
>>Lug nut torque was not the cause of the warpage on your rotors, hasn't
>>been an issue in brake rotor warpage for years, but the general public
>>won't let go of the idea.
>
>
> If that's true, why does Jeep provide a recommended torque range for lug
> nuts? Service procedures would be simpler for everyone if the
> manufacturer's specification was "85 lbs/ft minimum, user selects maximum".
>
>
>>The tire installer is not to blame.
>
>
> You say that random torquing wasn't a contributing factor, so that makes the
> tire installer's methods sound? Hell, even the tire busters at Costco use a
> torque wrench. If it didn't matter, would Costco bother?
>
>
>>The rotors being too thin to start with, along with driving habits, stop
>>and go or city driving, and overdriving the brakes (driving too fast,
>>stopping at the last moment) are the most often the cause of brake
>>pulsations, like it or not.
>
>
> Not in this case. The Jeep is babied. Driving habits are excellent. A
> Ford Thunderbird we owned previously (which was notoriously known for rotor
> warpage) didn't exhibit any brake problems in 40,000 miles, likely because
> of proper driving habits.
>
>
>>The variations in lug nut torque are not out of line in the real world,
>>rust, contamination, imperfect threads, grease, and dirt all affect the
>>torque of the lug nuts. In perfect, laboratory conditions, with perfectly
>>clean studs and nuts, lightly oiled, and a perfectly calibrated torque
>>wrench, you might get 'em close, but that's not the real world.
>
>
> I guess I'm pickier than most, because I refuse to use an impact wrench on
> the lug nuts of any of my vehicles. Interestingly, the Jeep is the only
> vehicle I've owned that needed rotor replacement before it needed a brake
> job.
>
>
>>By the way, with aluminum or magnesium wheels, lug nuts should be
>>retorqued after driving 50 to 100 miles. ALWAYS.
>
>
> You're right about that one. I learned that back in the 70s, when I worked
> for Chrysler. I still have the same Snap-On Torqometer that I used back
> then to torque lug nuts, including vehicles with left-handed threads on the
> left side.
>
>
>>Spdloader
>>
>>
>>"klutz" <klutz@klutzville.net> wrote in message
>>news:Azdwf.8592$V.4423@fed1read04...
>>
>>>My wife's 2003 Grand Cherokee fell victim to warped rotors, but after
>>>completing the repairs, I'm surmising that her driving style didn't cause
>>>the problem. While removing the lug nuts with a breaker bar, I felt a
>>>disparity in the effort required to loosen them. Hmmm. That can't be
>>>good. I wondered what the torque was on the other wheel, so I used a
>>>torque wrench to loosen the lugs. Torque varied from 80 to 125 lb/ft on
>>>the R/F wheel! Just for safety's sake, I checked the rear wheels. Same
>>>sad shape. Torque was all over the map. Moral of the story - when the
>>>dealer is doing warranty work (power window) and asks if you want your
>>>tires rotated - tell 'em "No, thanks" - unless you can oversee the job.
>>>Incidentally, the old rotors and pads had 29,000 miles and wore evenly,
>>>with no glazing or hot spots. The pads have 5/16 of friction material
>>>left. My money says that the dealer's tire-jockey has caused me (and
>>>likely many others) to suffer from warped rotors. Intentionally,
>>>perhaps? Hard to prove. Word to the wise - the 2003 WJ has rotors made
>>>of soft cast iron. Inattention to wheel torque can destroy them in a
>>>heartbeat.
>>>
>>
>>
>
>
--
Jerry Bransford
PP-ASEL N6TAY
See the Geezer Jeep at
http://members.***.net/jerrypb/
Guest
Posts: n/a
Re: Lug nut torque & warped rotors
Apparently you assume I was just making it all up.
All the information I gave you was straight out of the manual from a
Chrysler sponsored school, in order to receive my instructor certificate in
brakes and front end, not that it makes me the authority on it, but the
information never let me down when training my own techs.
>> The rotors on your GC are made from two parts, the rotor, and the "hat".
>> The hat is the part of the rotor that the wheel studs go through and your
>> wheels bolt to. Further, the hat of the rotor rests flat against the
>> wheel hub assembly, and you'll not warp that with 250ft. lbs of torque,
>> much less the 125 you specified finding. The hat uses a different type of
>> metal from the metal in the rotor, specifically to keep lug nut torque
>> from being an issue with the rotors.
>
> If the manufacturer changed the rotors to a 2-piece design with dissimilar
> metals to guard against problems caused by over/under torquing, why in the
> world have they continued to ignore the cross-section thickness of the
> rotor? I agree that a thicker rotor (e.g., Brembo) will minimize the
> probability of warpage. If Jeep's engineers were genuinely concerned
> about the component, they would have re-engineered all known weaknesses,
> including warpage. I have to applaud Jeep's technology of rotor assembly.
> The joint between the 2 rotor pieces is absolutely indetectable to the
> naked eye.
1. To keep costs down, and 2. Cut into the metal with a brake lathe and
you'll see the difference.
>
>> Jeep changed over to this type of rotor during the first series of GC and
>> has used them since.
Let me clarify, the change was made by the aftermarket, somewhere around
1995, I don't recall the exact year. 1996 Model year Jeep GC had them from
the factory. I left the automotive industry in 2003, including the
instructor field. I don't know what changes have been made since.
>
> Jeep recognized the advantages of the Akebono caliper in 2002. When were
> the rotors changed to a 2-piece model?
>
>> Lug nut torque was not the cause of the warpage on your rotors, hasn't
>> been an issue in brake rotor warpage for years, but the general public
>> won't let go of the idea.
>
> If that's true, why does Jeep provide a recommended torque range for lug
> nuts? Service procedures would be simpler for everyone if the
> manufacturer's specification was "85 lbs/ft minimum, user selects
> maximum".
To keep the wheels from falling off.
>
>> The tire installer is not to blame.
>
> You say that random torquing wasn't a contributing factor, so that makes
> the tire installer's methods sound? Hell, even the tire busters at Costco
> use a torque wrench. If it didn't matter, would Costco bother?
I never said his methods were sound, I don't know what methods he used,
other than your description. I said he wasn't to blame. If the rotors warped
with that minimal amount of torque, then they were the culprit all along,
not the guy who tightened them.
Costco "bothers" in order to keep the wheels from falling off and getting
sued. It happens more than you think. W/O's, (wheel offs) were the number 2
problem with a vehicle with "mags" after a brake job for comebacks, right
behind brake squeal as complaints go for #1.
>
>> The rotors being too thin to start with, along with driving habits, stop
>> and go or city driving, and overdriving the brakes (driving too fast,
>> stopping at the last moment) are the most often the cause of brake
>> pulsations, like it or not.
>
> Not in this case. The Jeep is babied. Driving habits are excellent. A
> Ford Thunderbird we owned previously (which was notoriously known for
> rotor warpage) didn't exhibit any brake problems in 40,000 miles, likely
> because of proper driving habits.
There are exceptions to every rule. My wife bought a new '04 Explorer.
Warped rotors within the first 300 miles. I was allowed to inspect them
after they were replaced. Both had stress cracks, obviously manufacturing
defects. Possibly an alternative cause for your problem.
>
>> The variations in lug nut torque are not out of line in the real world,
>> rust, contamination, imperfect threads, grease, and dirt all affect the
>> torque of the lug nuts. In perfect, laboratory conditions, with perfectly
>> clean studs and nuts, lightly oiled, and a perfectly calibrated torque
>> wrench, you might get 'em close, but that's not the real world.
>
> I guess I'm pickier than most, because I refuse to use an impact wrench on
> the lug nuts of any of my vehicles. Interestingly, the Jeep is the only
> vehicle I've owned that needed rotor replacement before it needed a brake
> job.
Then you don't know about the Ford Explorer from it's inception until about
2001.
>
>> By the way, with aluminum or magnesium wheels, lug nuts should be
>> retorqued after driving 50 to 100 miles. ALWAYS.
>
> You're right about that one. I learned that back in the 70s, when I
> worked for Chrysler. I still have the same Snap-On Torqometer that I used
> back then to torque lug nuts, including vehicles with left-handed threads
> on the left side.
>
>> Spdloader
>>
>>
>> "klutz" <klutz@klutzville.net> wrote in message
>> news:Azdwf.8592$V.4423@fed1read04...
>>> My wife's 2003 Grand Cherokee fell victim to warped rotors, but after
>>> completing the repairs, I'm surmising that her driving style didn't
>>> cause the problem. While removing the lug nuts with a breaker bar, I
>>> felt a disparity in the effort required to loosen them. Hmmm. That
>>> can't be good. I wondered what the torque was on the other wheel, so I
>>> used a torque wrench to loosen the lugs. Torque varied from 80 to 125
>>> lb/ft on the R/F wheel! Just for safety's sake, I checked the rear
>>> wheels. Same sad shape. Torque was all over the map. Moral of the
>>> story - when the dealer is doing warranty work (power window) and asks
>>> if you want your tires rotated - tell 'em "No, thanks" - unless you can
>>> oversee the job. Incidentally, the old rotors and pads had 29,000 miles
>>> and wore evenly, with no glazing or hot spots. The pads have 5/16 of
>>> friction material left. My money says that the dealer's tire-jockey has
>>> caused me (and likely many others) to suffer from warped rotors.
>>> Intentionally, perhaps? Hard to prove. Word to the wise - the 2003 WJ
>>> has rotors made of soft cast iron. Inattention to wheel torque can
>>> destroy them in a heartbeat.
>>>
>>
>>
>
>
All the information I gave you was straight out of the manual from a
Chrysler sponsored school, in order to receive my instructor certificate in
brakes and front end, not that it makes me the authority on it, but the
information never let me down when training my own techs.
>> The rotors on your GC are made from two parts, the rotor, and the "hat".
>> The hat is the part of the rotor that the wheel studs go through and your
>> wheels bolt to. Further, the hat of the rotor rests flat against the
>> wheel hub assembly, and you'll not warp that with 250ft. lbs of torque,
>> much less the 125 you specified finding. The hat uses a different type of
>> metal from the metal in the rotor, specifically to keep lug nut torque
>> from being an issue with the rotors.
>
> If the manufacturer changed the rotors to a 2-piece design with dissimilar
> metals to guard against problems caused by over/under torquing, why in the
> world have they continued to ignore the cross-section thickness of the
> rotor? I agree that a thicker rotor (e.g., Brembo) will minimize the
> probability of warpage. If Jeep's engineers were genuinely concerned
> about the component, they would have re-engineered all known weaknesses,
> including warpage. I have to applaud Jeep's technology of rotor assembly.
> The joint between the 2 rotor pieces is absolutely indetectable to the
> naked eye.
1. To keep costs down, and 2. Cut into the metal with a brake lathe and
you'll see the difference.
>
>> Jeep changed over to this type of rotor during the first series of GC and
>> has used them since.
Let me clarify, the change was made by the aftermarket, somewhere around
1995, I don't recall the exact year. 1996 Model year Jeep GC had them from
the factory. I left the automotive industry in 2003, including the
instructor field. I don't know what changes have been made since.
>
> Jeep recognized the advantages of the Akebono caliper in 2002. When were
> the rotors changed to a 2-piece model?
>
>> Lug nut torque was not the cause of the warpage on your rotors, hasn't
>> been an issue in brake rotor warpage for years, but the general public
>> won't let go of the idea.
>
> If that's true, why does Jeep provide a recommended torque range for lug
> nuts? Service procedures would be simpler for everyone if the
> manufacturer's specification was "85 lbs/ft minimum, user selects
> maximum".
To keep the wheels from falling off.
>
>> The tire installer is not to blame.
>
> You say that random torquing wasn't a contributing factor, so that makes
> the tire installer's methods sound? Hell, even the tire busters at Costco
> use a torque wrench. If it didn't matter, would Costco bother?
I never said his methods were sound, I don't know what methods he used,
other than your description. I said he wasn't to blame. If the rotors warped
with that minimal amount of torque, then they were the culprit all along,
not the guy who tightened them.
Costco "bothers" in order to keep the wheels from falling off and getting
sued. It happens more than you think. W/O's, (wheel offs) were the number 2
problem with a vehicle with "mags" after a brake job for comebacks, right
behind brake squeal as complaints go for #1.
>
>> The rotors being too thin to start with, along with driving habits, stop
>> and go or city driving, and overdriving the brakes (driving too fast,
>> stopping at the last moment) are the most often the cause of brake
>> pulsations, like it or not.
>
> Not in this case. The Jeep is babied. Driving habits are excellent. A
> Ford Thunderbird we owned previously (which was notoriously known for
> rotor warpage) didn't exhibit any brake problems in 40,000 miles, likely
> because of proper driving habits.
There are exceptions to every rule. My wife bought a new '04 Explorer.
Warped rotors within the first 300 miles. I was allowed to inspect them
after they were replaced. Both had stress cracks, obviously manufacturing
defects. Possibly an alternative cause for your problem.
>
>> The variations in lug nut torque are not out of line in the real world,
>> rust, contamination, imperfect threads, grease, and dirt all affect the
>> torque of the lug nuts. In perfect, laboratory conditions, with perfectly
>> clean studs and nuts, lightly oiled, and a perfectly calibrated torque
>> wrench, you might get 'em close, but that's not the real world.
>
> I guess I'm pickier than most, because I refuse to use an impact wrench on
> the lug nuts of any of my vehicles. Interestingly, the Jeep is the only
> vehicle I've owned that needed rotor replacement before it needed a brake
> job.
Then you don't know about the Ford Explorer from it's inception until about
2001.
>
>> By the way, with aluminum or magnesium wheels, lug nuts should be
>> retorqued after driving 50 to 100 miles. ALWAYS.
>
> You're right about that one. I learned that back in the 70s, when I
> worked for Chrysler. I still have the same Snap-On Torqometer that I used
> back then to torque lug nuts, including vehicles with left-handed threads
> on the left side.
>
>> Spdloader
>>
>>
>> "klutz" <klutz@klutzville.net> wrote in message
>> news:Azdwf.8592$V.4423@fed1read04...
>>> My wife's 2003 Grand Cherokee fell victim to warped rotors, but after
>>> completing the repairs, I'm surmising that her driving style didn't
>>> cause the problem. While removing the lug nuts with a breaker bar, I
>>> felt a disparity in the effort required to loosen them. Hmmm. That
>>> can't be good. I wondered what the torque was on the other wheel, so I
>>> used a torque wrench to loosen the lugs. Torque varied from 80 to 125
>>> lb/ft on the R/F wheel! Just for safety's sake, I checked the rear
>>> wheels. Same sad shape. Torque was all over the map. Moral of the
>>> story - when the dealer is doing warranty work (power window) and asks
>>> if you want your tires rotated - tell 'em "No, thanks" - unless you can
>>> oversee the job. Incidentally, the old rotors and pads had 29,000 miles
>>> and wore evenly, with no glazing or hot spots. The pads have 5/16 of
>>> friction material left. My money says that the dealer's tire-jockey has
>>> caused me (and likely many others) to suffer from warped rotors.
>>> Intentionally, perhaps? Hard to prove. Word to the wise - the 2003 WJ
>>> has rotors made of soft cast iron. Inattention to wheel torque can
>>> destroy them in a heartbeat.
>>>
>>
>>
>
>
Guest
Posts: n/a
Re: Lug nut torque & warped rotors
Apparently you assume I was just making it all up.
All the information I gave you was straight out of the manual from a
Chrysler sponsored school, in order to receive my instructor certificate in
brakes and front end, not that it makes me the authority on it, but the
information never let me down when training my own techs.
>> The rotors on your GC are made from two parts, the rotor, and the "hat".
>> The hat is the part of the rotor that the wheel studs go through and your
>> wheels bolt to. Further, the hat of the rotor rests flat against the
>> wheel hub assembly, and you'll not warp that with 250ft. lbs of torque,
>> much less the 125 you specified finding. The hat uses a different type of
>> metal from the metal in the rotor, specifically to keep lug nut torque
>> from being an issue with the rotors.
>
> If the manufacturer changed the rotors to a 2-piece design with dissimilar
> metals to guard against problems caused by over/under torquing, why in the
> world have they continued to ignore the cross-section thickness of the
> rotor? I agree that a thicker rotor (e.g., Brembo) will minimize the
> probability of warpage. If Jeep's engineers were genuinely concerned
> about the component, they would have re-engineered all known weaknesses,
> including warpage. I have to applaud Jeep's technology of rotor assembly.
> The joint between the 2 rotor pieces is absolutely indetectable to the
> naked eye.
1. To keep costs down, and 2. Cut into the metal with a brake lathe and
you'll see the difference.
>
>> Jeep changed over to this type of rotor during the first series of GC and
>> has used them since.
Let me clarify, the change was made by the aftermarket, somewhere around
1995, I don't recall the exact year. 1996 Model year Jeep GC had them from
the factory. I left the automotive industry in 2003, including the
instructor field. I don't know what changes have been made since.
>
> Jeep recognized the advantages of the Akebono caliper in 2002. When were
> the rotors changed to a 2-piece model?
>
>> Lug nut torque was not the cause of the warpage on your rotors, hasn't
>> been an issue in brake rotor warpage for years, but the general public
>> won't let go of the idea.
>
> If that's true, why does Jeep provide a recommended torque range for lug
> nuts? Service procedures would be simpler for everyone if the
> manufacturer's specification was "85 lbs/ft minimum, user selects
> maximum".
To keep the wheels from falling off.
>
>> The tire installer is not to blame.
>
> You say that random torquing wasn't a contributing factor, so that makes
> the tire installer's methods sound? Hell, even the tire busters at Costco
> use a torque wrench. If it didn't matter, would Costco bother?
I never said his methods were sound, I don't know what methods he used,
other than your description. I said he wasn't to blame. If the rotors warped
with that minimal amount of torque, then they were the culprit all along,
not the guy who tightened them.
Costco "bothers" in order to keep the wheels from falling off and getting
sued. It happens more than you think. W/O's, (wheel offs) were the number 2
problem with a vehicle with "mags" after a brake job for comebacks, right
behind brake squeal as complaints go for #1.
>
>> The rotors being too thin to start with, along with driving habits, stop
>> and go or city driving, and overdriving the brakes (driving too fast,
>> stopping at the last moment) are the most often the cause of brake
>> pulsations, like it or not.
>
> Not in this case. The Jeep is babied. Driving habits are excellent. A
> Ford Thunderbird we owned previously (which was notoriously known for
> rotor warpage) didn't exhibit any brake problems in 40,000 miles, likely
> because of proper driving habits.
There are exceptions to every rule. My wife bought a new '04 Explorer.
Warped rotors within the first 300 miles. I was allowed to inspect them
after they were replaced. Both had stress cracks, obviously manufacturing
defects. Possibly an alternative cause for your problem.
>
>> The variations in lug nut torque are not out of line in the real world,
>> rust, contamination, imperfect threads, grease, and dirt all affect the
>> torque of the lug nuts. In perfect, laboratory conditions, with perfectly
>> clean studs and nuts, lightly oiled, and a perfectly calibrated torque
>> wrench, you might get 'em close, but that's not the real world.
>
> I guess I'm pickier than most, because I refuse to use an impact wrench on
> the lug nuts of any of my vehicles. Interestingly, the Jeep is the only
> vehicle I've owned that needed rotor replacement before it needed a brake
> job.
Then you don't know about the Ford Explorer from it's inception until about
2001.
>
>> By the way, with aluminum or magnesium wheels, lug nuts should be
>> retorqued after driving 50 to 100 miles. ALWAYS.
>
> You're right about that one. I learned that back in the 70s, when I
> worked for Chrysler. I still have the same Snap-On Torqometer that I used
> back then to torque lug nuts, including vehicles with left-handed threads
> on the left side.
>
>> Spdloader
>>
>>
>> "klutz" <klutz@klutzville.net> wrote in message
>> news:Azdwf.8592$V.4423@fed1read04...
>>> My wife's 2003 Grand Cherokee fell victim to warped rotors, but after
>>> completing the repairs, I'm surmising that her driving style didn't
>>> cause the problem. While removing the lug nuts with a breaker bar, I
>>> felt a disparity in the effort required to loosen them. Hmmm. That
>>> can't be good. I wondered what the torque was on the other wheel, so I
>>> used a torque wrench to loosen the lugs. Torque varied from 80 to 125
>>> lb/ft on the R/F wheel! Just for safety's sake, I checked the rear
>>> wheels. Same sad shape. Torque was all over the map. Moral of the
>>> story - when the dealer is doing warranty work (power window) and asks
>>> if you want your tires rotated - tell 'em "No, thanks" - unless you can
>>> oversee the job. Incidentally, the old rotors and pads had 29,000 miles
>>> and wore evenly, with no glazing or hot spots. The pads have 5/16 of
>>> friction material left. My money says that the dealer's tire-jockey has
>>> caused me (and likely many others) to suffer from warped rotors.
>>> Intentionally, perhaps? Hard to prove. Word to the wise - the 2003 WJ
>>> has rotors made of soft cast iron. Inattention to wheel torque can
>>> destroy them in a heartbeat.
>>>
>>
>>
>
>
All the information I gave you was straight out of the manual from a
Chrysler sponsored school, in order to receive my instructor certificate in
brakes and front end, not that it makes me the authority on it, but the
information never let me down when training my own techs.
>> The rotors on your GC are made from two parts, the rotor, and the "hat".
>> The hat is the part of the rotor that the wheel studs go through and your
>> wheels bolt to. Further, the hat of the rotor rests flat against the
>> wheel hub assembly, and you'll not warp that with 250ft. lbs of torque,
>> much less the 125 you specified finding. The hat uses a different type of
>> metal from the metal in the rotor, specifically to keep lug nut torque
>> from being an issue with the rotors.
>
> If the manufacturer changed the rotors to a 2-piece design with dissimilar
> metals to guard against problems caused by over/under torquing, why in the
> world have they continued to ignore the cross-section thickness of the
> rotor? I agree that a thicker rotor (e.g., Brembo) will minimize the
> probability of warpage. If Jeep's engineers were genuinely concerned
> about the component, they would have re-engineered all known weaknesses,
> including warpage. I have to applaud Jeep's technology of rotor assembly.
> The joint between the 2 rotor pieces is absolutely indetectable to the
> naked eye.
1. To keep costs down, and 2. Cut into the metal with a brake lathe and
you'll see the difference.
>
>> Jeep changed over to this type of rotor during the first series of GC and
>> has used them since.
Let me clarify, the change was made by the aftermarket, somewhere around
1995, I don't recall the exact year. 1996 Model year Jeep GC had them from
the factory. I left the automotive industry in 2003, including the
instructor field. I don't know what changes have been made since.
>
> Jeep recognized the advantages of the Akebono caliper in 2002. When were
> the rotors changed to a 2-piece model?
>
>> Lug nut torque was not the cause of the warpage on your rotors, hasn't
>> been an issue in brake rotor warpage for years, but the general public
>> won't let go of the idea.
>
> If that's true, why does Jeep provide a recommended torque range for lug
> nuts? Service procedures would be simpler for everyone if the
> manufacturer's specification was "85 lbs/ft minimum, user selects
> maximum".
To keep the wheels from falling off.
>
>> The tire installer is not to blame.
>
> You say that random torquing wasn't a contributing factor, so that makes
> the tire installer's methods sound? Hell, even the tire busters at Costco
> use a torque wrench. If it didn't matter, would Costco bother?
I never said his methods were sound, I don't know what methods he used,
other than your description. I said he wasn't to blame. If the rotors warped
with that minimal amount of torque, then they were the culprit all along,
not the guy who tightened them.
Costco "bothers" in order to keep the wheels from falling off and getting
sued. It happens more than you think. W/O's, (wheel offs) were the number 2
problem with a vehicle with "mags" after a brake job for comebacks, right
behind brake squeal as complaints go for #1.
>
>> The rotors being too thin to start with, along with driving habits, stop
>> and go or city driving, and overdriving the brakes (driving too fast,
>> stopping at the last moment) are the most often the cause of brake
>> pulsations, like it or not.
>
> Not in this case. The Jeep is babied. Driving habits are excellent. A
> Ford Thunderbird we owned previously (which was notoriously known for
> rotor warpage) didn't exhibit any brake problems in 40,000 miles, likely
> because of proper driving habits.
There are exceptions to every rule. My wife bought a new '04 Explorer.
Warped rotors within the first 300 miles. I was allowed to inspect them
after they were replaced. Both had stress cracks, obviously manufacturing
defects. Possibly an alternative cause for your problem.
>
>> The variations in lug nut torque are not out of line in the real world,
>> rust, contamination, imperfect threads, grease, and dirt all affect the
>> torque of the lug nuts. In perfect, laboratory conditions, with perfectly
>> clean studs and nuts, lightly oiled, and a perfectly calibrated torque
>> wrench, you might get 'em close, but that's not the real world.
>
> I guess I'm pickier than most, because I refuse to use an impact wrench on
> the lug nuts of any of my vehicles. Interestingly, the Jeep is the only
> vehicle I've owned that needed rotor replacement before it needed a brake
> job.
Then you don't know about the Ford Explorer from it's inception until about
2001.
>
>> By the way, with aluminum or magnesium wheels, lug nuts should be
>> retorqued after driving 50 to 100 miles. ALWAYS.
>
> You're right about that one. I learned that back in the 70s, when I
> worked for Chrysler. I still have the same Snap-On Torqometer that I used
> back then to torque lug nuts, including vehicles with left-handed threads
> on the left side.
>
>> Spdloader
>>
>>
>> "klutz" <klutz@klutzville.net> wrote in message
>> news:Azdwf.8592$V.4423@fed1read04...
>>> My wife's 2003 Grand Cherokee fell victim to warped rotors, but after
>>> completing the repairs, I'm surmising that her driving style didn't
>>> cause the problem. While removing the lug nuts with a breaker bar, I
>>> felt a disparity in the effort required to loosen them. Hmmm. That
>>> can't be good. I wondered what the torque was on the other wheel, so I
>>> used a torque wrench to loosen the lugs. Torque varied from 80 to 125
>>> lb/ft on the R/F wheel! Just for safety's sake, I checked the rear
>>> wheels. Same sad shape. Torque was all over the map. Moral of the
>>> story - when the dealer is doing warranty work (power window) and asks
>>> if you want your tires rotated - tell 'em "No, thanks" - unless you can
>>> oversee the job. Incidentally, the old rotors and pads had 29,000 miles
>>> and wore evenly, with no glazing or hot spots. The pads have 5/16 of
>>> friction material left. My money says that the dealer's tire-jockey has
>>> caused me (and likely many others) to suffer from warped rotors.
>>> Intentionally, perhaps? Hard to prove. Word to the wise - the 2003 WJ
>>> has rotors made of soft cast iron. Inattention to wheel torque can
>>> destroy them in a heartbeat.
>>>
>>
>>
>
>
Guest
Posts: n/a
Re: Lug nut torque & warped rotors
Apparently you assume I was just making it all up.
All the information I gave you was straight out of the manual from a
Chrysler sponsored school, in order to receive my instructor certificate in
brakes and front end, not that it makes me the authority on it, but the
information never let me down when training my own techs.
>> The rotors on your GC are made from two parts, the rotor, and the "hat".
>> The hat is the part of the rotor that the wheel studs go through and your
>> wheels bolt to. Further, the hat of the rotor rests flat against the
>> wheel hub assembly, and you'll not warp that with 250ft. lbs of torque,
>> much less the 125 you specified finding. The hat uses a different type of
>> metal from the metal in the rotor, specifically to keep lug nut torque
>> from being an issue with the rotors.
>
> If the manufacturer changed the rotors to a 2-piece design with dissimilar
> metals to guard against problems caused by over/under torquing, why in the
> world have they continued to ignore the cross-section thickness of the
> rotor? I agree that a thicker rotor (e.g., Brembo) will minimize the
> probability of warpage. If Jeep's engineers were genuinely concerned
> about the component, they would have re-engineered all known weaknesses,
> including warpage. I have to applaud Jeep's technology of rotor assembly.
> The joint between the 2 rotor pieces is absolutely indetectable to the
> naked eye.
1. To keep costs down, and 2. Cut into the metal with a brake lathe and
you'll see the difference.
>
>> Jeep changed over to this type of rotor during the first series of GC and
>> has used them since.
Let me clarify, the change was made by the aftermarket, somewhere around
1995, I don't recall the exact year. 1996 Model year Jeep GC had them from
the factory. I left the automotive industry in 2003, including the
instructor field. I don't know what changes have been made since.
>
> Jeep recognized the advantages of the Akebono caliper in 2002. When were
> the rotors changed to a 2-piece model?
>
>> Lug nut torque was not the cause of the warpage on your rotors, hasn't
>> been an issue in brake rotor warpage for years, but the general public
>> won't let go of the idea.
>
> If that's true, why does Jeep provide a recommended torque range for lug
> nuts? Service procedures would be simpler for everyone if the
> manufacturer's specification was "85 lbs/ft minimum, user selects
> maximum".
To keep the wheels from falling off.
>
>> The tire installer is not to blame.
>
> You say that random torquing wasn't a contributing factor, so that makes
> the tire installer's methods sound? Hell, even the tire busters at Costco
> use a torque wrench. If it didn't matter, would Costco bother?
I never said his methods were sound, I don't know what methods he used,
other than your description. I said he wasn't to blame. If the rotors warped
with that minimal amount of torque, then they were the culprit all along,
not the guy who tightened them.
Costco "bothers" in order to keep the wheels from falling off and getting
sued. It happens more than you think. W/O's, (wheel offs) were the number 2
problem with a vehicle with "mags" after a brake job for comebacks, right
behind brake squeal as complaints go for #1.
>
>> The rotors being too thin to start with, along with driving habits, stop
>> and go or city driving, and overdriving the brakes (driving too fast,
>> stopping at the last moment) are the most often the cause of brake
>> pulsations, like it or not.
>
> Not in this case. The Jeep is babied. Driving habits are excellent. A
> Ford Thunderbird we owned previously (which was notoriously known for
> rotor warpage) didn't exhibit any brake problems in 40,000 miles, likely
> because of proper driving habits.
There are exceptions to every rule. My wife bought a new '04 Explorer.
Warped rotors within the first 300 miles. I was allowed to inspect them
after they were replaced. Both had stress cracks, obviously manufacturing
defects. Possibly an alternative cause for your problem.
>
>> The variations in lug nut torque are not out of line in the real world,
>> rust, contamination, imperfect threads, grease, and dirt all affect the
>> torque of the lug nuts. In perfect, laboratory conditions, with perfectly
>> clean studs and nuts, lightly oiled, and a perfectly calibrated torque
>> wrench, you might get 'em close, but that's not the real world.
>
> I guess I'm pickier than most, because I refuse to use an impact wrench on
> the lug nuts of any of my vehicles. Interestingly, the Jeep is the only
> vehicle I've owned that needed rotor replacement before it needed a brake
> job.
Then you don't know about the Ford Explorer from it's inception until about
2001.
>
>> By the way, with aluminum or magnesium wheels, lug nuts should be
>> retorqued after driving 50 to 100 miles. ALWAYS.
>
> You're right about that one. I learned that back in the 70s, when I
> worked for Chrysler. I still have the same Snap-On Torqometer that I used
> back then to torque lug nuts, including vehicles with left-handed threads
> on the left side.
>
>> Spdloader
>>
>>
>> "klutz" <klutz@klutzville.net> wrote in message
>> news:Azdwf.8592$V.4423@fed1read04...
>>> My wife's 2003 Grand Cherokee fell victim to warped rotors, but after
>>> completing the repairs, I'm surmising that her driving style didn't
>>> cause the problem. While removing the lug nuts with a breaker bar, I
>>> felt a disparity in the effort required to loosen them. Hmmm. That
>>> can't be good. I wondered what the torque was on the other wheel, so I
>>> used a torque wrench to loosen the lugs. Torque varied from 80 to 125
>>> lb/ft on the R/F wheel! Just for safety's sake, I checked the rear
>>> wheels. Same sad shape. Torque was all over the map. Moral of the
>>> story - when the dealer is doing warranty work (power window) and asks
>>> if you want your tires rotated - tell 'em "No, thanks" - unless you can
>>> oversee the job. Incidentally, the old rotors and pads had 29,000 miles
>>> and wore evenly, with no glazing or hot spots. The pads have 5/16 of
>>> friction material left. My money says that the dealer's tire-jockey has
>>> caused me (and likely many others) to suffer from warped rotors.
>>> Intentionally, perhaps? Hard to prove. Word to the wise - the 2003 WJ
>>> has rotors made of soft cast iron. Inattention to wheel torque can
>>> destroy them in a heartbeat.
>>>
>>
>>
>
>
All the information I gave you was straight out of the manual from a
Chrysler sponsored school, in order to receive my instructor certificate in
brakes and front end, not that it makes me the authority on it, but the
information never let me down when training my own techs.
>> The rotors on your GC are made from two parts, the rotor, and the "hat".
>> The hat is the part of the rotor that the wheel studs go through and your
>> wheels bolt to. Further, the hat of the rotor rests flat against the
>> wheel hub assembly, and you'll not warp that with 250ft. lbs of torque,
>> much less the 125 you specified finding. The hat uses a different type of
>> metal from the metal in the rotor, specifically to keep lug nut torque
>> from being an issue with the rotors.
>
> If the manufacturer changed the rotors to a 2-piece design with dissimilar
> metals to guard against problems caused by over/under torquing, why in the
> world have they continued to ignore the cross-section thickness of the
> rotor? I agree that a thicker rotor (e.g., Brembo) will minimize the
> probability of warpage. If Jeep's engineers were genuinely concerned
> about the component, they would have re-engineered all known weaknesses,
> including warpage. I have to applaud Jeep's technology of rotor assembly.
> The joint between the 2 rotor pieces is absolutely indetectable to the
> naked eye.
1. To keep costs down, and 2. Cut into the metal with a brake lathe and
you'll see the difference.
>
>> Jeep changed over to this type of rotor during the first series of GC and
>> has used them since.
Let me clarify, the change was made by the aftermarket, somewhere around
1995, I don't recall the exact year. 1996 Model year Jeep GC had them from
the factory. I left the automotive industry in 2003, including the
instructor field. I don't know what changes have been made since.
>
> Jeep recognized the advantages of the Akebono caliper in 2002. When were
> the rotors changed to a 2-piece model?
>
>> Lug nut torque was not the cause of the warpage on your rotors, hasn't
>> been an issue in brake rotor warpage for years, but the general public
>> won't let go of the idea.
>
> If that's true, why does Jeep provide a recommended torque range for lug
> nuts? Service procedures would be simpler for everyone if the
> manufacturer's specification was "85 lbs/ft minimum, user selects
> maximum".
To keep the wheels from falling off.
>
>> The tire installer is not to blame.
>
> You say that random torquing wasn't a contributing factor, so that makes
> the tire installer's methods sound? Hell, even the tire busters at Costco
> use a torque wrench. If it didn't matter, would Costco bother?
I never said his methods were sound, I don't know what methods he used,
other than your description. I said he wasn't to blame. If the rotors warped
with that minimal amount of torque, then they were the culprit all along,
not the guy who tightened them.
Costco "bothers" in order to keep the wheels from falling off and getting
sued. It happens more than you think. W/O's, (wheel offs) were the number 2
problem with a vehicle with "mags" after a brake job for comebacks, right
behind brake squeal as complaints go for #1.
>
>> The rotors being too thin to start with, along with driving habits, stop
>> and go or city driving, and overdriving the brakes (driving too fast,
>> stopping at the last moment) are the most often the cause of brake
>> pulsations, like it or not.
>
> Not in this case. The Jeep is babied. Driving habits are excellent. A
> Ford Thunderbird we owned previously (which was notoriously known for
> rotor warpage) didn't exhibit any brake problems in 40,000 miles, likely
> because of proper driving habits.
There are exceptions to every rule. My wife bought a new '04 Explorer.
Warped rotors within the first 300 miles. I was allowed to inspect them
after they were replaced. Both had stress cracks, obviously manufacturing
defects. Possibly an alternative cause for your problem.
>
>> The variations in lug nut torque are not out of line in the real world,
>> rust, contamination, imperfect threads, grease, and dirt all affect the
>> torque of the lug nuts. In perfect, laboratory conditions, with perfectly
>> clean studs and nuts, lightly oiled, and a perfectly calibrated torque
>> wrench, you might get 'em close, but that's not the real world.
>
> I guess I'm pickier than most, because I refuse to use an impact wrench on
> the lug nuts of any of my vehicles. Interestingly, the Jeep is the only
> vehicle I've owned that needed rotor replacement before it needed a brake
> job.
Then you don't know about the Ford Explorer from it's inception until about
2001.
>
>> By the way, with aluminum or magnesium wheels, lug nuts should be
>> retorqued after driving 50 to 100 miles. ALWAYS.
>
> You're right about that one. I learned that back in the 70s, when I
> worked for Chrysler. I still have the same Snap-On Torqometer that I used
> back then to torque lug nuts, including vehicles with left-handed threads
> on the left side.
>
>> Spdloader
>>
>>
>> "klutz" <klutz@klutzville.net> wrote in message
>> news:Azdwf.8592$V.4423@fed1read04...
>>> My wife's 2003 Grand Cherokee fell victim to warped rotors, but after
>>> completing the repairs, I'm surmising that her driving style didn't
>>> cause the problem. While removing the lug nuts with a breaker bar, I
>>> felt a disparity in the effort required to loosen them. Hmmm. That
>>> can't be good. I wondered what the torque was on the other wheel, so I
>>> used a torque wrench to loosen the lugs. Torque varied from 80 to 125
>>> lb/ft on the R/F wheel! Just for safety's sake, I checked the rear
>>> wheels. Same sad shape. Torque was all over the map. Moral of the
>>> story - when the dealer is doing warranty work (power window) and asks
>>> if you want your tires rotated - tell 'em "No, thanks" - unless you can
>>> oversee the job. Incidentally, the old rotors and pads had 29,000 miles
>>> and wore evenly, with no glazing or hot spots. The pads have 5/16 of
>>> friction material left. My money says that the dealer's tire-jockey has
>>> caused me (and likely many others) to suffer from warped rotors.
>>> Intentionally, perhaps? Hard to prove. Word to the wise - the 2003 WJ
>>> has rotors made of soft cast iron. Inattention to wheel torque can
>>> destroy them in a heartbeat.
>>>
>>
>>
>
>
Guest
Posts: n/a
Re: Lug nut torque & warped rotors
Wrong or right, my information came from a school Chrysler gave on their
braking systems I attended in 1996.
Cost is most often the driving factor, I think. Spend the least they can get
away with.
Spdloader
"Jerry Bransford" <jerrypb@***.net> wrote in message
news:Cojwf.8771$V.4697@fed1read04...
> Klutz and Spdloader,
>
> Composite rotors used for several years on Jeeps were not installed by the
> factory to lessen rotor warping. They were a cost-reduced and
> significantly lightened rotor that warped so easily that Jeep went back to
> all-cast rotor. They were so light in weight that they weren't able to
> resist warping from both heat and uneven lugnut tightening. Newer
> Wranglers and JGCs have all-cast rotors that are far better able to
> resist heat and uneven-tightening induced warping.
>
> Jerry
>
> klutz wrote:
>> Your explanation is clear, but difficult to accept.
>>
>> "Spdloader" <askforit@nospam.triad.rr.com> wrote in message
>> news:rlhwf.4160$Kp.3269@southeast.rr.com...
>>
>>>The rotors on your GC are made from two parts, the rotor, and the "hat".
>>>The hat is the part of the rotor that the wheel studs go through and your
>>>wheels bolt to. Further, the hat of the rotor rests flat against the
>>>wheel hub assembly, and you'll not warp that with 250ft. lbs of torque,
>>>much less the 125 you specified finding. The hat uses a different type of
>>>metal from the metal in the rotor, specifically to keep lug nut torque
>>>from being an issue with the rotors.
>>
>>
>> If the manufacturer changed the rotors to a 2-piece design with
>> dissimilar metals to guard against problems caused by over/under
>> torquing, why in the world have they continued to ignore the
>> cross-section thickness of the rotor? I agree that a thicker rotor
>> (e.g., Brembo) will minimize the probability of warpage. If Jeep's
>> engineers were genuinely concerned about the component, they would have
>> re-engineered all known weaknesses, including warpage. I have to applaud
>> Jeep's technology of rotor assembly. The joint between the 2 rotor
>> pieces is absolutely indetectable to the naked eye.
>>
>>
>>>Jeep changed over to this type of rotor during the first series of GC and
>>>has used them since.
>>
>>
>> Jeep recognized the advantages of the Akebono caliper in 2002. When were
>> the rotors changed to a 2-piece model?
>>
>>
>>>Lug nut torque was not the cause of the warpage on your rotors, hasn't
>>>been an issue in brake rotor warpage for years, but the general public
>>>won't let go of the idea.
>>
>>
>> If that's true, why does Jeep provide a recommended torque range for lug
>> nuts? Service procedures would be simpler for everyone if the
>> manufacturer's specification was "85 lbs/ft minimum, user selects
>> maximum".
>>
>>
>>>The tire installer is not to blame.
>>
>>
>> You say that random torquing wasn't a contributing factor, so that makes
>> the tire installer's methods sound? Hell, even the tire busters at
>> Costco use a torque wrench. If it didn't matter, would Costco bother?
>>
>>
>>>The rotors being too thin to start with, along with driving habits, stop
>>>and go or city driving, and overdriving the brakes (driving too fast,
>>>stopping at the last moment) are the most often the cause of brake
>>>pulsations, like it or not.
>>
>>
>> Not in this case. The Jeep is babied. Driving habits are excellent. A
>> Ford Thunderbird we owned previously (which was notoriously known for
>> rotor warpage) didn't exhibit any brake problems in 40,000 miles, likely
>> because of proper driving habits.
>>
>>
>>>The variations in lug nut torque are not out of line in the real world,
>>>rust, contamination, imperfect threads, grease, and dirt all affect the
>>>torque of the lug nuts. In perfect, laboratory conditions, with perfectly
>>>clean studs and nuts, lightly oiled, and a perfectly calibrated torque
>>>wrench, you might get 'em close, but that's not the real world.
>>
>>
>> I guess I'm pickier than most, because I refuse to use an impact wrench
>> on the lug nuts of any of my vehicles. Interestingly, the Jeep is the
>> only vehicle I've owned that needed rotor replacement before it needed a
>> brake job.
>>
>>
>>>By the way, with aluminum or magnesium wheels, lug nuts should be
>>>retorqued after driving 50 to 100 miles. ALWAYS.
>>
>>
>> You're right about that one. I learned that back in the 70s, when I
>> worked for Chrysler. I still have the same Snap-On Torqometer that I
>> used back then to torque lug nuts, including vehicles with left-handed
>> threads on the left side.
>>
>>
>>>Spdloader
>>>
>>>
>>>"klutz" <klutz@klutzville.net> wrote in message
>>>news:Azdwf.8592$V.4423@fed1read04...
>>>
>>>>My wife's 2003 Grand Cherokee fell victim to warped rotors, but after
>>>>completing the repairs, I'm surmising that her driving style didn't
>>>>cause the problem. While removing the lug nuts with a breaker bar, I
>>>>felt a disparity in the effort required to loosen them. Hmmm. That
>>>>can't be good. I wondered what the torque was on the other wheel, so I
>>>>used a torque wrench to loosen the lugs. Torque varied from 80 to 125
>>>>lb/ft on the R/F wheel! Just for safety's sake, I checked the rear
>>>>wheels. Same sad shape. Torque was all over the map. Moral of the
>>>>story - when the dealer is doing warranty work (power window) and asks
>>>>if you want your tires rotated - tell 'em "No, thanks" - unless you can
>>>>oversee the job. Incidentally, the old rotors and pads had 29,000 miles
>>>>and wore evenly, with no glazing or hot spots. The pads have 5/16 of
>>>>friction material left. My money says that the dealer's tire-jockey has
>>>>caused me (and likely many others) to suffer from warped rotors.
>>>>Intentionally, perhaps? Hard to prove. Word to the wise - the 2003 WJ
>>>>has rotors made of soft cast iron. Inattention to wheel torque can
>>>>destroy them in a heartbeat.
>>>>
>>>
>>>
>>
>>
>
> --
> Jerry Bransford
> PP-ASEL N6TAY
> See the Geezer Jeep at
> http://members.***.net/jerrypb/
braking systems I attended in 1996.
Cost is most often the driving factor, I think. Spend the least they can get
away with.
Spdloader
"Jerry Bransford" <jerrypb@***.net> wrote in message
news:Cojwf.8771$V.4697@fed1read04...
> Klutz and Spdloader,
>
> Composite rotors used for several years on Jeeps were not installed by the
> factory to lessen rotor warping. They were a cost-reduced and
> significantly lightened rotor that warped so easily that Jeep went back to
> all-cast rotor. They were so light in weight that they weren't able to
> resist warping from both heat and uneven lugnut tightening. Newer
> Wranglers and JGCs have all-cast rotors that are far better able to
> resist heat and uneven-tightening induced warping.
>
> Jerry
>
> klutz wrote:
>> Your explanation is clear, but difficult to accept.
>>
>> "Spdloader" <askforit@nospam.triad.rr.com> wrote in message
>> news:rlhwf.4160$Kp.3269@southeast.rr.com...
>>
>>>The rotors on your GC are made from two parts, the rotor, and the "hat".
>>>The hat is the part of the rotor that the wheel studs go through and your
>>>wheels bolt to. Further, the hat of the rotor rests flat against the
>>>wheel hub assembly, and you'll not warp that with 250ft. lbs of torque,
>>>much less the 125 you specified finding. The hat uses a different type of
>>>metal from the metal in the rotor, specifically to keep lug nut torque
>>>from being an issue with the rotors.
>>
>>
>> If the manufacturer changed the rotors to a 2-piece design with
>> dissimilar metals to guard against problems caused by over/under
>> torquing, why in the world have they continued to ignore the
>> cross-section thickness of the rotor? I agree that a thicker rotor
>> (e.g., Brembo) will minimize the probability of warpage. If Jeep's
>> engineers were genuinely concerned about the component, they would have
>> re-engineered all known weaknesses, including warpage. I have to applaud
>> Jeep's technology of rotor assembly. The joint between the 2 rotor
>> pieces is absolutely indetectable to the naked eye.
>>
>>
>>>Jeep changed over to this type of rotor during the first series of GC and
>>>has used them since.
>>
>>
>> Jeep recognized the advantages of the Akebono caliper in 2002. When were
>> the rotors changed to a 2-piece model?
>>
>>
>>>Lug nut torque was not the cause of the warpage on your rotors, hasn't
>>>been an issue in brake rotor warpage for years, but the general public
>>>won't let go of the idea.
>>
>>
>> If that's true, why does Jeep provide a recommended torque range for lug
>> nuts? Service procedures would be simpler for everyone if the
>> manufacturer's specification was "85 lbs/ft minimum, user selects
>> maximum".
>>
>>
>>>The tire installer is not to blame.
>>
>>
>> You say that random torquing wasn't a contributing factor, so that makes
>> the tire installer's methods sound? Hell, even the tire busters at
>> Costco use a torque wrench. If it didn't matter, would Costco bother?
>>
>>
>>>The rotors being too thin to start with, along with driving habits, stop
>>>and go or city driving, and overdriving the brakes (driving too fast,
>>>stopping at the last moment) are the most often the cause of brake
>>>pulsations, like it or not.
>>
>>
>> Not in this case. The Jeep is babied. Driving habits are excellent. A
>> Ford Thunderbird we owned previously (which was notoriously known for
>> rotor warpage) didn't exhibit any brake problems in 40,000 miles, likely
>> because of proper driving habits.
>>
>>
>>>The variations in lug nut torque are not out of line in the real world,
>>>rust, contamination, imperfect threads, grease, and dirt all affect the
>>>torque of the lug nuts. In perfect, laboratory conditions, with perfectly
>>>clean studs and nuts, lightly oiled, and a perfectly calibrated torque
>>>wrench, you might get 'em close, but that's not the real world.
>>
>>
>> I guess I'm pickier than most, because I refuse to use an impact wrench
>> on the lug nuts of any of my vehicles. Interestingly, the Jeep is the
>> only vehicle I've owned that needed rotor replacement before it needed a
>> brake job.
>>
>>
>>>By the way, with aluminum or magnesium wheels, lug nuts should be
>>>retorqued after driving 50 to 100 miles. ALWAYS.
>>
>>
>> You're right about that one. I learned that back in the 70s, when I
>> worked for Chrysler. I still have the same Snap-On Torqometer that I
>> used back then to torque lug nuts, including vehicles with left-handed
>> threads on the left side.
>>
>>
>>>Spdloader
>>>
>>>
>>>"klutz" <klutz@klutzville.net> wrote in message
>>>news:Azdwf.8592$V.4423@fed1read04...
>>>
>>>>My wife's 2003 Grand Cherokee fell victim to warped rotors, but after
>>>>completing the repairs, I'm surmising that her driving style didn't
>>>>cause the problem. While removing the lug nuts with a breaker bar, I
>>>>felt a disparity in the effort required to loosen them. Hmmm. That
>>>>can't be good. I wondered what the torque was on the other wheel, so I
>>>>used a torque wrench to loosen the lugs. Torque varied from 80 to 125
>>>>lb/ft on the R/F wheel! Just for safety's sake, I checked the rear
>>>>wheels. Same sad shape. Torque was all over the map. Moral of the
>>>>story - when the dealer is doing warranty work (power window) and asks
>>>>if you want your tires rotated - tell 'em "No, thanks" - unless you can
>>>>oversee the job. Incidentally, the old rotors and pads had 29,000 miles
>>>>and wore evenly, with no glazing or hot spots. The pads have 5/16 of
>>>>friction material left. My money says that the dealer's tire-jockey has
>>>>caused me (and likely many others) to suffer from warped rotors.
>>>>Intentionally, perhaps? Hard to prove. Word to the wise - the 2003 WJ
>>>>has rotors made of soft cast iron. Inattention to wheel torque can
>>>>destroy them in a heartbeat.
>>>>
>>>
>>>
>>
>>
>
> --
> Jerry Bransford
> PP-ASEL N6TAY
> See the Geezer Jeep at
> http://members.***.net/jerrypb/
