Yup, the mallet trick sometimes tells all.

Hopefully you got it before the slip rings got damaged.

I would do one more test just to see if the mallet did something else.
I would run a battery booster cable from the battery negative to the
alternator case and see if the charging goes stable. If so, the
alternator case would have a bad ground that the hit moved slightly. It
is a sneaky one, but seems to happen on Jeeps a lot.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's - Gone to the rust pile...
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)

Odd-Inge Larsen wrote:
> I did charge the battery. Seems ok now. Probably just low due to alternator
> failing.
>
> Did try to knock on the alternator with a rubber mallet. This probably moved
> the brushes some and the voltmeter jumped to about 14 volts, its normal
> position. But it fluctuated a great deal and the interior lights flickered a
> lot. Revved it up and it was not able to charge anymore. Let off the
> throttle and it charged again.
>
> My diagnoses: Worn brushes in the alternator. Replace brushes or by new
> alternator.
>
> Does this seem like a reasonable diagnosis?
>
> regards
> Odd-Inge
>
> "Odd-Inge Larsen" <oddingelarsen@dcpost.no> wrote in message
> news:f5k6hg$ckd$1@troll.powertech.no...
>> Noticed today that my voltmeter was well in the red while driving to the
>> store. No problem starting yet but only drove 3 km.
>>
>> This is on a 1990 Jeep Cherokee 4.0L
>>
>> Something like this happend some years ago and then I had to get a new
>> alternator. Suspect the same this time, but would like some tips on what
>> to check before ordering a new alternator or having a mechanic check this
>> out.
>>
>> I have a battery tester and a multimeter at hand. I plan to first check
>> the battery with the tester to see if it works ok with load. Then measure
>> battery volts when the car is not running (should be something like 12V)
>> and when car is running (should be higher, preferably 14.4V).
>>
>> Of course I will try cleaning battery connections (Optima red top battery,
>> some years old).
>>
>> Anything else I could check?
>>
>> regards
>> Odd-Inge Larsen
>> North Norway
>>
>
>

 

Tried the cable trick. Made no difference.
As it is difficult to get new brushes where I live and the label on the
alternator can not be read without removing alternator I ordered a new
alternator. Also one could never know if anything else was damaged inside.

Dealer wanted nkr 4041,- for the original part and it had to be shipped from
Germany.
Found a new 100A (in stock) at a store located at the norwegian Amcar club
for nkr 1763,- included VAT and shipping. (aprox US$ 271)

Hope to have it fixed later this week if all goes well. Thanks for the help
guys.

Odd-Inge

"Mike Romain" <romainm@sympatico.ca> wrote in message
news:467e8e71$0$11813$9a6e19ea@unlimited.newshosti ng.com...
> Yup, the mallet trick sometimes tells all.
>
> Hopefully you got it before the slip rings got damaged.
>
> I would do one more test just to see if the mallet did something else. I
> would run a battery booster cable from the battery negative to the
> alternator case and see if the charging goes stable. If so, the
> alternator case would have a bad ground that the hit moved slightly. It
> is a sneaky one, but seems to happen on Jeeps a lot.
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's - Gone to the rust pile...
> Canadian Off Road Trips Photos: Non members can still view!
> Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
> (More Off Road album links at bottom of the view page)
>
> Odd-Inge Larsen wrote:
>> I did charge the battery. Seems ok now. Probably just low due to
>> alternator failing.
>>
>> Did try to knock on the alternator with a rubber mallet. This probably
>> moved the brushes some and the voltmeter jumped to about 14 volts, its
>> normal position. But it fluctuated a great deal and the interior lights
>> flickered a lot. Revved it up and it was not able to charge anymore. Let
>> off the throttle and it charged again.
>>
>> My diagnoses: Worn brushes in the alternator. Replace brushes or by new
>> alternator.
>>
>> Does this seem like a reasonable diagnosis?
>>
>> regards
>> Odd-Inge
>>
>> "Odd-Inge Larsen" <oddingelarsen@dcpost.no> wrote in message
>> news:f5k6hg$ckd$1@troll.powertech.no...
>>> Noticed today that my voltmeter was well in the red while driving to the
>>> store. No problem starting yet but only drove 3 km.
>>>
>>> This is on a 1990 Jeep Cherokee 4.0L
>>>
>>> Something like this happend some years ago and then I had to get a new
>>> alternator. Suspect the same this time, but would like some tips on what
>>> to check before ordering a new alternator or having a mechanic check
>>> this out.
>>>
>>> I have a battery tester and a multimeter at hand. I plan to first check
>>> the battery with the tester to see if it works ok with load. Then
>>> measure battery volts when the car is not running (should be something
>>> like 12V) and when car is running (should be higher, preferably 14.4V).
>>>
>>> Of course I will try cleaning battery connections (Optima red top
>>> battery, some years old).
>>>
>>> Anything else I could check?
>>>
>>> regards
>>> Odd-Inge Larsen
>>> North Norway
>>>
>>

 

Tried the cable trick. Made no difference.
As it is difficult to get new brushes where I live and the label on the
alternator can not be read without removing alternator I ordered a new
alternator. Also one could never know if anything else was damaged inside.

Dealer wanted nkr 4041,- for the original part and it had to be shipped from
Germany.
Found a new 100A (in stock) at a store located at the norwegian Amcar club
for nkr 1763,- included VAT and shipping. (aprox US$ 271)

Hope to have it fixed later this week if all goes well. Thanks for the help
guys.

Odd-Inge

"Mike Romain" <romainm@sympatico.ca> wrote in message
news:467e8e71$0$11813$9a6e19ea@unlimited.newshosti ng.com...
> Yup, the mallet trick sometimes tells all.
>
> Hopefully you got it before the slip rings got damaged.
>
> I would do one more test just to see if the mallet did something else. I
> would run a battery booster cable from the battery negative to the
> alternator case and see if the charging goes stable. If so, the
> alternator case would have a bad ground that the hit moved slightly. It
> is a sneaky one, but seems to happen on Jeeps a lot.
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's - Gone to the rust pile...
> Canadian Off Road Trips Photos: Non members can still view!
> Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
> (More Off Road album links at bottom of the view page)
>
> Odd-Inge Larsen wrote:
>> I did charge the battery. Seems ok now. Probably just low due to
>> alternator failing.
>>
>> Did try to knock on the alternator with a rubber mallet. This probably
>> moved the brushes some and the voltmeter jumped to about 14 volts, its
>> normal position. But it fluctuated a great deal and the interior lights
>> flickered a lot. Revved it up and it was not able to charge anymore. Let
>> off the throttle and it charged again.
>>
>> My diagnoses: Worn brushes in the alternator. Replace brushes or by new
>> alternator.
>>
>> Does this seem like a reasonable diagnosis?
>>
>> regards
>> Odd-Inge
>>
>> "Odd-Inge Larsen" <oddingelarsen@dcpost.no> wrote in message
>> news:f5k6hg$ckd$1@troll.powertech.no...
>>> Noticed today that my voltmeter was well in the red while driving to the
>>> store. No problem starting yet but only drove 3 km.
>>>
>>> This is on a 1990 Jeep Cherokee 4.0L
>>>
>>> Something like this happend some years ago and then I had to get a new
>>> alternator. Suspect the same this time, but would like some tips on what
>>> to check before ordering a new alternator or having a mechanic check
>>> this out.
>>>
>>> I have a battery tester and a multimeter at hand. I plan to first check
>>> the battery with the tester to see if it works ok with load. Then
>>> measure battery volts when the car is not running (should be something
>>> like 12V) and when car is running (should be higher, preferably 14.4V).
>>>
>>> Of course I will try cleaning battery connections (Optima red top
>>> battery, some years old).
>>>
>>> Anything else I could check?
>>>
>>> regards
>>> Odd-Inge Larsen
>>> North Norway
>>>
>>

 

Tried the cable trick. Made no difference.
As it is difficult to get new brushes where I live and the label on the
alternator can not be read without removing alternator I ordered a new
alternator. Also one could never know if anything else was damaged inside.

Dealer wanted nkr 4041,- for the original part and it had to be shipped from
Germany.
Found a new 100A (in stock) at a store located at the norwegian Amcar club
for nkr 1763,- included VAT and shipping. (aprox US$ 271)

Hope to have it fixed later this week if all goes well. Thanks for the help
guys.

Odd-Inge

"Mike Romain" <romainm@sympatico.ca> wrote in message
news:467e8e71$0$11813$9a6e19ea@unlimited.newshosti ng.com...
> Yup, the mallet trick sometimes tells all.
>
> Hopefully you got it before the slip rings got damaged.
>
> I would do one more test just to see if the mallet did something else. I
> would run a battery booster cable from the battery negative to the
> alternator case and see if the charging goes stable. If so, the
> alternator case would have a bad ground that the hit moved slightly. It
> is a sneaky one, but seems to happen on Jeeps a lot.
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's - Gone to the rust pile...
> Canadian Off Road Trips Photos: Non members can still view!
> Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
> (More Off Road album links at bottom of the view page)
>
> Odd-Inge Larsen wrote:
>> I did charge the battery. Seems ok now. Probably just low due to
>> alternator failing.
>>
>> Did try to knock on the alternator with a rubber mallet. This probably
>> moved the brushes some and the voltmeter jumped to about 14 volts, its
>> normal position. But it fluctuated a great deal and the interior lights
>> flickered a lot. Revved it up and it was not able to charge anymore. Let
>> off the throttle and it charged again.
>>
>> My diagnoses: Worn brushes in the alternator. Replace brushes or by new
>> alternator.
>>
>> Does this seem like a reasonable diagnosis?
>>
>> regards
>> Odd-Inge
>>
>> "Odd-Inge Larsen" <oddingelarsen@dcpost.no> wrote in message
>> news:f5k6hg$ckd$1@troll.powertech.no...
>>> Noticed today that my voltmeter was well in the red while driving to the
>>> store. No problem starting yet but only drove 3 km.
>>>
>>> This is on a 1990 Jeep Cherokee 4.0L
>>>
>>> Something like this happend some years ago and then I had to get a new
>>> alternator. Suspect the same this time, but would like some tips on what
>>> to check before ordering a new alternator or having a mechanic check
>>> this out.
>>>
>>> I have a battery tester and a multimeter at hand. I plan to first check
>>> the battery with the tester to see if it works ok with load. Then
>>> measure battery volts when the car is not running (should be something
>>> like 12V) and when car is running (should be higher, preferably 14.4V).
>>>
>>> Of course I will try cleaning battery connections (Optima red top
>>> battery, some years old).
>>>
>>> Anything else I could check?
>>>
>>> regards
>>> Odd-Inge Larsen
>>> North Norway
>>>
>>

 

Tried the cable trick. Made no difference.
As it is difficult to get new brushes where I live and the label on the
alternator can not be read without removing alternator I ordered a new
alternator. Also one could never know if anything else was damaged inside.

Dealer wanted nkr 4041,- for the original part and it had to be shipped from
Germany.
Found a new 100A (in stock) at a store located at the norwegian Amcar club
for nkr 1763,- included VAT and shipping. (aprox US$ 271)

Hope to have it fixed later this week if all goes well. Thanks for the help
guys.

Odd-Inge

"Mike Romain" <romainm@sympatico.ca> wrote in message
news:467e8e71$0$11813$9a6e19ea@unlimited.newshosti ng.com...
> Yup, the mallet trick sometimes tells all.
>
> Hopefully you got it before the slip rings got damaged.
>
> I would do one more test just to see if the mallet did something else. I
> would run a battery booster cable from the battery negative to the
> alternator case and see if the charging goes stable. If so, the
> alternator case would have a bad ground that the hit moved slightly. It
> is a sneaky one, but seems to happen on Jeeps a lot.
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's - Gone to the rust pile...
> Canadian Off Road Trips Photos: Non members can still view!
> Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
> (More Off Road album links at bottom of the view page)
>
> Odd-Inge Larsen wrote:
>> I did charge the battery. Seems ok now. Probably just low due to
>> alternator failing.
>>
>> Did try to knock on the alternator with a rubber mallet. This probably
>> moved the brushes some and the voltmeter jumped to about 14 volts, its
>> normal position. But it fluctuated a great deal and the interior lights
>> flickered a lot. Revved it up and it was not able to charge anymore. Let
>> off the throttle and it charged again.
>>
>> My diagnoses: Worn brushes in the alternator. Replace brushes or by new
>> alternator.
>>
>> Does this seem like a reasonable diagnosis?
>>
>> regards
>> Odd-Inge
>>
>> "Odd-Inge Larsen" <oddingelarsen@dcpost.no> wrote in message
>> news:f5k6hg$ckd$1@troll.powertech.no...
>>> Noticed today that my voltmeter was well in the red while driving to the
>>> store. No problem starting yet but only drove 3 km.
>>>
>>> This is on a 1990 Jeep Cherokee 4.0L
>>>
>>> Something like this happend some years ago and then I had to get a new
>>> alternator. Suspect the same this time, but would like some tips on what
>>> to check before ordering a new alternator or having a mechanic check
>>> this out.
>>>
>>> I have a battery tester and a multimeter at hand. I plan to first check
>>> the battery with the tester to see if it works ok with load. Then
>>> measure battery volts when the car is not running (should be something
>>> like 12V) and when car is running (should be higher, preferably 14.4V).
>>>
>>> Of course I will try cleaning battery connections (Optima red top
>>> battery, some years old).
>>>
>>> Anything else I could check?
>>>
>>> regards
>>> Odd-Inge Larsen
>>> North Norway
>>>
>>

 

On Jun 23, 3:23 pm, "Odd-Inge Larsen" <oddingelar...@dcpost.no> wrote:
> Noticed today that my voltmeter was well in the red while driving to the
> store. No problem starting yet but only drove 3 km.
>
> This is on a 1990 Jeep Cherokee 4.0L
>
> Something like this happend some years ago and then I had to get a new
> alternator. Suspect the same this time, but would like some tips on what to
> check before ordering a new alternator or having a mechanic check this out.
>
> I have a battery tester and a multimeter at hand. I plan to first check the
> battery with the tester to see if it works ok with load. Then measure
> battery volts when the car is not running (should be something like 12V) and
> when car is running (should be higher, preferably 14.4V).
>
> Of course I will try cleaning battery connections (Optima red top battery,
> some years old).
>
> Anything else I could check?
>
> regards
> Odd-Inge Larsen
> North Norway

Make sure the exciter wire has a good connection, it's the small one
going to the alt.......Have a good day

 

On Jun 23, 3:23 pm, "Odd-Inge Larsen" <oddingelar...@dcpost.no> wrote:
> Noticed today that my voltmeter was well in the red while driving to the
> store. No problem starting yet but only drove 3 km.
>
> This is on a 1990 Jeep Cherokee 4.0L
>
> Something like this happend some years ago and then I had to get a new
> alternator. Suspect the same this time, but would like some tips on what to
> check before ordering a new alternator or having a mechanic check this out.
>
> I have a battery tester and a multimeter at hand. I plan to first check the
> battery with the tester to see if it works ok with load. Then measure
> battery volts when the car is not running (should be something like 12V) and
> when car is running (should be higher, preferably 14.4V).
>
> Of course I will try cleaning battery connections (Optima red top battery,
> some years old).
>
> Anything else I could check?
>
> regards
> Odd-Inge Larsen
> North Norway

Make sure the exciter wire has a good connection, it's the small one
going to the alt.......Have a good day

 

On Jun 23, 3:23 pm, "Odd-Inge Larsen" <oddingelar...@dcpost.no> wrote:
> Noticed today that my voltmeter was well in the red while driving to the
> store. No problem starting yet but only drove 3 km.
>
> This is on a 1990 Jeep Cherokee 4.0L
>
> Something like this happend some years ago and then I had to get a new
> alternator. Suspect the same this time, but would like some tips on what to
> check before ordering a new alternator or having a mechanic check this out.
>
> I have a battery tester and a multimeter at hand. I plan to first check the
> battery with the tester to see if it works ok with load. Then measure
> battery volts when the car is not running (should be something like 12V) and
> when car is running (should be higher, preferably 14.4V).
>
> Of course I will try cleaning battery connections (Optima red top battery,
> some years old).
>
> Anything else I could check?
>
> regards
> Odd-Inge Larsen
> North Norway

Make sure the exciter wire has a good connection, it's the small one
going to the alt.......Have a good day

 

On Jun 23, 3:23 pm, "Odd-Inge Larsen" <oddingelar...@dcpost.no> wrote:
> Noticed today that my voltmeter was well in the red while driving to the
> store. No problem starting yet but only drove 3 km.
>
> This is on a 1990 Jeep Cherokee 4.0L
>
> Something like this happend some years ago and then I had to get a new
> alternator. Suspect the same this time, but would like some tips on what to
> check before ordering a new alternator or having a mechanic check this out.
>
> I have a battery tester and a multimeter at hand. I plan to first check the
> battery with the tester to see if it works ok with load. Then measure
> battery volts when the car is not running (should be something like 12V) and
> when car is running (should be higher, preferably 14.4V).
>
> Of course I will try cleaning battery connections (Optima red top battery,
> some years old).
>
> Anything else I could check?
>
> regards
> Odd-Inge Larsen
> North Norway

Make sure the exciter wire has a good connection, it's the small one
going to the alt.......Have a good day

 

Have now changed alternator. Bits was falling out of the old one when I took
it out. Something had smashed the internal cooling fan blades.
The new one is working fine. Charging around 14 volts again :-) And much
more quiet.

Odd-Inge

"Odd-Inge Larsen" <oddingelarsen@dcpost.no> wrote in message
news:f5k6hg$ckd$1@troll.powertech.no...
> Noticed today that my voltmeter was well in the red while driving to the
> store. No problem starting yet but only drove 3 km.
>
> This is on a 1990 Jeep Cherokee 4.0L
>
> Something like this happend some years ago and then I had to get a new
> alternator. Suspect the same this time, but would like some tips on what
> to check before ordering a new alternator or having a mechanic check this
> out.
>
> I have a battery tester and a multimeter at hand. I plan to first check
> the battery with the tester to see if it works ok with load. Then measure
> battery volts when the car is not running (should be something like 12V)
> and when car is running (should be higher, preferably 14.4V).
>
> Of course I will try cleaning battery connections (Optima red top battery,
> some years old).
>
> Anything else I could check?
>
> regards
> Odd-Inge Larsen
> North Norway
>