Cherokee Brake Problems-Brake Booster?
 

When i'm driving, sometimes there will be brake pressure and somtimes
there won't. If i apply pressure for a few seconds, the pedal loses
presure and goes to the floor. I have to pump the brakes to get the car
to stop. I tried bleeding the brakes and got through the back to wheels
fine, but when i tried to bleed the front right brake, air bubbles kept
coming out. After refilling the resivoir for the 3rd time (it never got
completly empty), i got the idea that it might be somethign more
complicated. I was able to bleed the front left with no problems but
the same thing kept happening when i tried to drive it. I checked all
the lines and can't find any leaks, but i have an oil leak so i might
be missing something thinking its just oil and not brake fluid. There
is some black fluid underneath where the brake booster connects to the
master cylinder but i don't konw if its coming out of there or is oil .
I can also hear some air come out of the brake booster inside the car
but i dont' know if that is normal. My brake fuild is also pretty dark,
i know i should flush it out and replace it but could that be the
problem? I don't know too much about brakes
and i don't want to take apart the whole system before i know what to
look for. Any ideas?

Re: Cherokee Brake Problems-Brake Booster?
 

tyytyy22 did pass the time by typing:
> When i'm driving, sometimes there will be brake pressure and somtimes
> there won't. If i apply pressure for a few seconds, the pedal loses
> presure and goes to the floor. I have to pump the brakes to get the car
> to stop. I tried bleeding the brakes and got through the back to wheels
> fine, but when i tried to bleed the front right brake, air bubbles kept
> coming out. After refilling the resivoir for the 3rd time (it never got
> completly empty), i got the idea that it might be somethign more
> complicated. I was able to bleed the front left with no problems but
> the same thing kept happening when i tried to drive it. I checked all
> the lines and can't find any leaks, but i have an oil leak so i might
> be missing something thinking its just oil and not brake fluid. There
> is some black fluid underneath where the brake booster connects to the
> master cylinder but i don't konw if its coming out of there or is oil .
> I can also hear some air come out of the brake booster inside the car
> but i dont' know if that is normal. My brake fuild is also pretty dark,
> i know i should flush it out and replace it but could that be the
> problem? I don't know too much about brakes
> and i don't want to take apart the whole system before i know what to
> look for. Any ideas?

If your getting fluid from between the booster and master cyl or
coming out the bottom of the booster (and it's not spilled or leaking
from the connections) then your master cyl needs to be rebuilt/replaced.
Front and rear are seperate pistons in the master cyl.

Barring that I'd be checking the proportioning valve for leaks.

Loosing pedal pressure (without seeing a massive puddle of brake
fluid under the Jeep) makes me about 90% sure it's your master cyl.

--
DougW

Re: Cherokee Brake Problems-Brake Booster?
 

tyytyy22 did pass the time by typing:
> When i'm driving, sometimes there will be brake pressure and somtimes
> there won't. If i apply pressure for a few seconds, the pedal loses
> presure and goes to the floor. I have to pump the brakes to get the car
> to stop. I tried bleeding the brakes and got through the back to wheels
> fine, but when i tried to bleed the front right brake, air bubbles kept
> coming out. After refilling the resivoir for the 3rd time (it never got
> completly empty), i got the idea that it might be somethign more
> complicated. I was able to bleed the front left with no problems but
> the same thing kept happening when i tried to drive it. I checked all
> the lines and can't find any leaks, but i have an oil leak so i might
> be missing something thinking its just oil and not brake fluid. There
> is some black fluid underneath where the brake booster connects to the
> master cylinder but i don't konw if its coming out of there or is oil .
> I can also hear some air come out of the brake booster inside the car
> but i dont' know if that is normal. My brake fuild is also pretty dark,
> i know i should flush it out and replace it but could that be the
> problem? I don't know too much about brakes
> and i don't want to take apart the whole system before i know what to
> look for. Any ideas?

If your getting fluid from between the booster and master cyl or
coming out the bottom of the booster (and it's not spilled or leaking
from the connections) then your master cyl needs to be rebuilt/replaced.
Front and rear are seperate pistons in the master cyl.

Barring that I'd be checking the proportioning valve for leaks.

Loosing pedal pressure (without seeing a massive puddle of brake
fluid under the Jeep) makes me about 90% sure it's your master cyl.

--
DougW

Re: Cherokee Brake Problems-Brake Booster?
 

tyytyy22 did pass the time by typing:
> When i'm driving, sometimes there will be brake pressure and somtimes
> there won't. If i apply pressure for a few seconds, the pedal loses
> presure and goes to the floor. I have to pump the brakes to get the car
> to stop. I tried bleeding the brakes and got through the back to wheels
> fine, but when i tried to bleed the front right brake, air bubbles kept
> coming out. After refilling the resivoir for the 3rd time (it never got
> completly empty), i got the idea that it might be somethign more
> complicated. I was able to bleed the front left with no problems but
> the same thing kept happening when i tried to drive it. I checked all
> the lines and can't find any leaks, but i have an oil leak so i might
> be missing something thinking its just oil and not brake fluid. There
> is some black fluid underneath where the brake booster connects to the
> master cylinder but i don't konw if its coming out of there or is oil .
> I can also hear some air come out of the brake booster inside the car
> but i dont' know if that is normal. My brake fuild is also pretty dark,
> i know i should flush it out and replace it but could that be the
> problem? I don't know too much about brakes
> and i don't want to take apart the whole system before i know what to
> look for. Any ideas?

If your getting fluid from between the booster and master cyl or
coming out the bottom of the booster (and it's not spilled or leaking
from the connections) then your master cyl needs to be rebuilt/replaced.
Front and rear are seperate pistons in the master cyl.

Barring that I'd be checking the proportioning valve for leaks.

Loosing pedal pressure (without seeing a massive puddle of brake
fluid under the Jeep) makes me about 90% sure it's your master cyl.

--
DougW

Re: Cherokee Brake Problems-Brake Booster?
 

thanks for the help. if i took out the master cylinder and replaced all
the parts in one of these kits:
http://www.tellico4x4.com/catalog/pr...ducts_id/13305
do you think it would work? or should i just buy a new master cylinder?

Re: Cherokee Brake Problems-Brake Booster?
 

thanks for the help. if i took out the master cylinder and replaced all
the parts in one of these kits:
http://www.tellico4x4.com/catalog/pr...ducts_id/13305
do you think it would work? or should i just buy a new master cylinder?

Re: Cherokee Brake Problems-Brake Booster?
 

thanks for the help. if i took out the master cylinder and replaced all
the parts in one of these kits:
http://www.tellico4x4.com/catalog/pr...ducts_id/13305
do you think it would work? or should i just buy a new master cylinder?

Re: Cherokee Brake Problems-Brake Booster?
 

If depends.... do you have the hones, etc that would be required to do it
yourself?

Master Cylinders don't cost that much to buy remanufactured and if you have
another vehicle you can remove your current one beforehand and avoid paying
the core charge ($20-$25) They will also (usually) come with a small kit
for bleeding before installation.

As a final note I would use suggest that you use the synthetic DOT 4 fluid
instead of the standard DOT 3. It is less attractive to water which leads
to less corrosion in the system (the black gunk), has a higher boiling
point, and only costs an additional $1 per quart.
http://www.valvoline.com/pages/produ...asp?product=51


"tyytyy22" <ssejk5@yahoo.com> wrote in message
news:1138587676.477175.6370@z14g2000cwz.googlegrou ps.com...
> thanks for the help. if i took out the master cylinder and replaced all
> the parts in one of these kits:
> http://www.tellico4x4.com/catalog/pr...ducts_id/13305
> do you think it would work? or should i just buy a new master cylinder?
>

Re: Cherokee Brake Problems-Brake Booster?
 

If depends.... do you have the hones, etc that would be required to do it
yourself?

Master Cylinders don't cost that much to buy remanufactured and if you have
another vehicle you can remove your current one beforehand and avoid paying
the core charge ($20-$25) They will also (usually) come with a small kit
for bleeding before installation.

As a final note I would use suggest that you use the synthetic DOT 4 fluid
instead of the standard DOT 3. It is less attractive to water which leads
to less corrosion in the system (the black gunk), has a higher boiling
point, and only costs an additional $1 per quart.
http://www.valvoline.com/pages/produ...asp?product=51


"tyytyy22" <ssejk5@yahoo.com> wrote in message
news:1138587676.477175.6370@z14g2000cwz.googlegrou ps.com...
> thanks for the help. if i took out the master cylinder and replaced all
> the parts in one of these kits:
> http://www.tellico4x4.com/catalog/pr...ducts_id/13305
> do you think it would work? or should i just buy a new master cylinder?
>

Re: Cherokee Brake Problems-Brake Booster?
 

If depends.... do you have the hones, etc that would be required to do it
yourself?

Master Cylinders don't cost that much to buy remanufactured and if you have
another vehicle you can remove your current one beforehand and avoid paying
the core charge ($20-$25) They will also (usually) come with a small kit
for bleeding before installation.

As a final note I would use suggest that you use the synthetic DOT 4 fluid
instead of the standard DOT 3. It is less attractive to water which leads
to less corrosion in the system (the black gunk), has a higher boiling
point, and only costs an additional $1 per quart.
http://www.valvoline.com/pages/produ...asp?product=51


"tyytyy22" <ssejk5@yahoo.com> wrote in message
news:1138587676.477175.6370@z14g2000cwz.googlegrou ps.com...
> thanks for the help. if i took out the master cylinder and replaced all
> the parts in one of these kits:
> http://www.tellico4x4.com/catalog/pr...ducts_id/13305
> do you think it would work? or should i just buy a new master cylinder?
>