Alternator Rebuild Bearing P/N's

Like idler pulleys the bearings in the alternator don't stay happy in the mud. I would like to do the economical thing and just replace the bearings in the alternator but there doesn't seem to be any information online (lots for first and second gen). Truck is my daily, so I don't want to double dismantle. Does anyone know the bearing p/n's used in the OEM alternator, or have an old one they are willing to investigate?

SOLVED: Details in the linked post here: https://www.tacomaworld.com/threads/alternator-rebuild-bearing-p-ns.806507/#post-28922491

 

If you are doing a lot of mudding, have you considered just buying a used alternator and having a spare you can rebuild?

 

http://commercialalternatorandstarter.com/

 

if using a daily driver to mud, I'd expand on your idea and get a used beater truck, so OP has a spare to get to work
(only half kidding,,, well, an 1/8th kidding)

 

I 100% agree with your sentiments in getting a second for mudding. It's not intended mudding. I usually try and stay out of the deep stuff but sometimes it's inevitable even if unintentional.

 

I’ve never heard of anyone replacing alternator bearings. How do you know they are bad? Did you inspect them?

They might have an identifier on them that you could use to source replacements, but they might cost more than a new alternator.

I’m skeptical that occasional mudding is significantly harder on alternators than driving on the road during a Minnesota winter. I do both and haven’t replaced an alternator bearing.

I also too avoid mud most of the time, but where I live it’s often unavoidable if you travel off the beaten path. It can also be a lot of fun in moderation.

 

Probing around with an improvised stethoscope on the alt with a characteristic bearing rumble/groan at idle. Everything else is quiet when probed.

Likely, but need to dismantle and potentially remove the bearings to read a number or measure. Buying single bearings from a supplier is almost universally cheaper than buying an assembly. For the size I would be surprised if each bearing would be more than $30ea. Expensive but still cheaper than an oem alt. Remans from Rock auto are ~$200CAD

Agree that normal trail mud/puddle is not that accelerative if your not going that deep to flood the engine bay/ push a bow wave. I have had no problems or indications of such until they became submerged and stuck in sandy silty junk. Deep but clear water has had little effect.

 

Back in the "old days" you could buy alternator kits like this one for a GM Delcotron 10SI, I fixed dozens of them.
The old Chrysler alternators would quit charging, you could get them going by replacing one brush on the car if the access was good.

We fixed Ford starters with brushes & bushings for a few dollars.

Good days, gone forever...



Or a master kit with more parts:

 

Gave these guys a call and they do have bearings available for the alt. $50CAD for the set!!! I'll report back with bearing p/n's once installed and confirmed.

@MannyS Your Texan knowledge of shops that are local to me un uncanny

 

Oh Ya! These are some chowdered bearings.

https://youtube.com/shorts/AccisbRyHto?feature=share

 

I spent years at a bench rebuilding starters, alternators, and generators from 1993-1995.

@somebody you will have to split the case to remove the stator first. Then you may be able to read the cartridge bearing shield #### number. Most of the time the front bearing is held in the case with a bolted-on plate which has to be removed.
!Warning! The brushes and springs may fly away when you remove the stator from the rear case!

 

Thanks for the tips. As I can get the parts today (albeit probably at a premium) I am going that route. Splitting to get bearing numbers that I may or may not be able to have next day shipped (no second car to go picking up) is just a bit more than I want to risk right now.

 

I also once circa 1987 replaced the brushes in the alternator on my 1981 Datsun pickup that was not charging. I don't remember replacing any bearings though.

 

Great success with parts from http://commercialalternatorandstarter.com/.

The NTN 6303LLU and 6202LLU are the correct sized for the front and rear bearings respectively. While i was picking up the bearings I grabbed a set of brushes. The ones that came out were probably half worn and sticky from dirt (probably could just be cleaned. The slip rings were still in good condition.

What Came out:




The slip rings were fingernail smooth (looks crappy in pic for some reason) but you can tell the upper brush wasn't wiping very well and removing the oxidation


Front bearing held in with a retainer plate. Easily tapped out with a hammer and arbor press new one in.


Rear bearing cant use a puller because the slip ring assembly. Because the shaft is slit to hold the slip ring assembly its not that tight and came off with some gentle prying using 2 screwdrivers. Recommend a drop if penetrant and cleaning the shaft above the bearing with some sandpaper so it doesnt get hung up on the way off. THere is a plastic cap that goes over the rear bearing. It is keyed to the rear housing and should be installed in the housing first on reassembly.



140kkm brush with the new one. theres also a handy little wire hole to hold the brushes back for installation.



The rectifiers should run a little cooler now with a clean.

 

Nice job on the write up.

Koyo bearings, good reliable brand.

Old GM alternators (10SI, etc) had the hole to hold the brushes retracted in the retainer, a straw from a WD-40 can fit perfectly and wouldn't scratch the brush face.

 

Thanks. In this case it was an old brake pad spring. (fixed the double pic in the post)

 

These guys worked on my RV alternator when I had issues while driving within Canada a long long time ago

 

Thanks for that write up. I don't know of any cleaver way to remember things like this so I'll just post a link to my build thread, so I can find it....