Noise from altenator or vibration damper?

There is a noticable noise now and it pretty much sounds like its near the alternator. The sound is almost like 2 parts hitting each other, ratchet/clunking type sound. Belt squeals alittle when first started but thats it. Also my belt has an obvious wear pattern to it. Only 2/3 of the belt look worn. about 1/3 of the belt looks "darker"( less worn).

I have no other common issues with alternator failure. everything runs and starts fine right now, no voltage problems, just this noise.
Now I've done some research and suspect its the alternator bearing or pully issue because of similar posts with noise problems.

If its the bearing the whole alternator needs to be replaced?
Now would I be able to tell by taking off belt and trying to move that pully?
Is that the easiest way or is it possible to determine that way?


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89 cherokee manual 4.0L/ RE 4.5" lift / 33" pro comp mud terrain/ PORC SYE-231 w/ custom shaft

Take off the belt. Move the ALT pully up and down, then in and out. If it has a play, replace it. I had that problem on my 72 Chev, and the front ALT berring was shot. It ate into the case, it had so much in and out play.

You can probably rebuild it, or just get a new one. A shop that specializes in that kind of stuff can replace just what is bad, it its even the alternator.

Check your balancer too, make sure it didn't separate and isnt rubbing the timing chain cover. if your belt is off track that could be the cause. I just replaced my balancer for this reason, it rubbed a hole right through the cover.

The alternator on my 90 made an annoying noise. I suspect it was the bearing. It made a "rubbing" noise when the engine was on.

If it's the HD, you might need a new timing cover as well. Quick check (to isolate the fault) - lay a straightedge across the front of the HD - the leading edges of the hub and the inertia ring should be nearly flush (a little rubber squidging out - say, 1/16"-1/8" - is fairly normal. More, and it's shot.) "Ring Walk" on the HD is a good way to have a belt end up off-track.

Failing alternator bearings can also knock a belt off track, if they're bad enough. The front bearing is good for this. If you're got an alternator bearing failing enough to cause the belt to jump, I'd scrap the case and get a new one - it's not worth rebuilding at that point (I've seen seized bearings on alternators chew up cases. You try doing mechanical work for the best part of 30 years and see what sort of weird stuff you run across...)

Ditto on finding a local shop to do rewinds - I've not had good luck with "big chain" alternators, and a search here will tell you others have the same no luck. If you can't find a local shop, click the link in my sig, then click "San Jose Generator" for the shop that does all my work - he does mail order now, and people here have used his goods with excellent results.

5-90

Yes it is still fairly flush. it only lookes like a Little rubber squidging out which is why im more towards the alternator being the issue. I know what it looks like to when it walks, my friend just replaced his.

Instead of rebuilding I plan on just replacing.
Upgrade to one over 100a, stock are 90a right?

Any good upgrades for around $150 ?