Is this an impending alternator failure?

[Weaver]

'88 3.2 litre Carrera, approx. 90K miles, original alternator.

Went to change plugs and inspect fan belt yesterday and found this:



For some reason the pic keeps uploading upside down on all three of my computers, anyway. The marks are on bottom left of the fan housing.

So does this look like an impending bearing failure, or something more sinister?

I'm guessing the first thing to do is remove the fan belt and check if there is any free play with the fan.

Any suggestions would be helpful.

Thanks for y'all time.

[na2ub]

I'd say you are on the right track. The tolerences are close, but you certainly shouldn't scrape. Is your fan belt too tight? Either your alternator bearings are worn, or the alternator is not mounted properly (bolts all tight).

[ivangene]

you already said what to do - pull the belt and check it

there is always the chance it was a prior failure....

[Tippy]

If it is the bearing that is failing but it still charges, you can simply replace the bearing.

Those bearings are cheap.

An easy inspection to see the life left of the alternator is pull the voltage regulator off and look at the brushes and copper slip rings. It is only 2 bolts and 2 blade terminals. When mine went out recently, one brush had a funky angle worn into from being completely consumed. The slip rings were both severely ground into (one looked like it was nearing 0.080-0.100" depth by my naked eye) requiring replacement.

[bazar01]

Originally Posted by Weaver

'88 3.2 litre Carrera, approx. 90K miles, original alternator.

Went to change plugs and inspect fan belt yesterday and found this:



For some reason the pic keeps uploading upside down on all three of my computers, anyway. The marks are on bottom left of the fan housing.

So does this look like an impending bearing failure, or something more sinister?

I'm guessing the first thing to do is remove the fan belt and check if there is any free play with the fan.

Any suggestions would be helpful.

Thanks for y'all time.

I had the same scrape marks on my fan housing in the bottom. Belt tensions are correct. So I pulled my alternator and found out the alternator rear bearing housing was worn causing the back alternator shaft to move up causing the fan blade to make contact on the bottom of housing. Took the alternator to an old school alternator shop. He changed the nearings, sleeved the housing and changed the regulator/brush assembly for far cheaper than getting a new or remanned alternator.
Hopefully you only have a bad/loose bearing. But the way the blade is scraping the outer housing, it is a worn bearing housing.
Good luck.

[euro911sc]

FYI: Those also appear if your fan shroud strap has been tightened too much. It makes the shroud out of round and the fan tips scrape the inside like that. the strap need not be gorilla tight at all.

-Michael

[Weaver]

Thank you everyone for your replies.

Well, there is no play in the alternator as far as I could tell. And the band was not over tighten. There is however a slight click when you spin the fan. Not a grinding, but a click.

So out it came. But now I can't for the life of me get the alternator out of the fan housing. Everything I read states it should just slide out with some light tapes, but I was using a brass hammer and brass punch on the studs trying to get it to budge. I did heat the housing up alittle with a torch to try to get it to expand from the alternator, but I'm so afraid of cracking the fan housing. Anyone run into this problem?

There is some small, black plastic pieces falling out of the altenator when I move it around on the bench. They crumble apart when you try to pick them up. So I still think the bearings are about to let go.

My alternator is a Paris Rhone. Is that the corrected one? I thought they were all Bosch my 1988. Everything looked and came apart stock and I have no indication from my records that the alternator ever came out.

Thanks for y'all time

[Tippy]

I had the same issue because of the powder coating making it too tight.

I kept hitting with a hammer and a 2 X 4 gingerely until it broke free.

[pete3799]

Just replaced mine.
Shoot some PB Blaster down the studs and around the perimeter of the alt. let it soak a while.
I started the nuts back on flush with the studs and used a hard wood block to rap on the studs.
Go easy.... a little here and a little there and it will eventually drop out.
Hardest part for me was getting the fan off. Tried the drop it (alt. shaft) on a block of wood procedure many times and couldn't get it to budge. Then the forcefully slam it onto the block of wood procedure which did get it off but it also cracked the rear housing (were the bearing resides) of the alt. so use caution.
Ended up buying a new alt.

[Porboynz]

I have literally just sat down after replacing a noisy bearing in the alternator and read this post. I could hear an odd rumbling/russling noise for the past 500 miles when the engine was cold. With the assembly on the bench and the brush assembly removed you could just hear the noise when spinning the fan, but there was absolutely no movement in the bearing. Once the bearing was out on the bench it would pass the spin test, so it was only protesting when it had the fan/fanbelt load on it. I find it hard to believe a bearing could be so far gone that it allowed the 1mm + movement you would need to have the fan hit the housing, surely the bearing must be rumbling and protesting real bad way before that happens? I think that over tightening the band and or some debris preventing it seating properly on the engine case which distorts the housing would be likely suspects.

Those fan housings are very fragile so support it with wooden blocks as much as you can when you are encouraging the alternator to drop out. I would say you have corrosion in the bolt holes, maybe the same around the alternator perimeter. Soak it with penetrating oil and give it some time, I think you would need a dangerous amount of heat to get to all those threaded rods and the housing recess.

Maybe gentle pressure on all the protruding threaded rods at the same time with a plate in a press and then some cautious tapping around threaded rods and the housing might do it. A little sidewise percussion can spring a seized bolt loose again same as smacking the side of a taper ball joint will often release it. Go easy though, that fan housing will break if you look at it with any sort of aggravation. I doubt that the bearings are the source of that black stuff, more likely carbon black residue from the brushes.

Good luck with it. It will come loose, eventually.

[Rich Gas]

The black stuff is probably the original engine sound pad...mine was everywhere. My fan loved that stuff.

[kanadary]

have you checked the alternator housing/fan shroud? is the mg housing cracked? i would think its a shifting alternator and its starting to close up the gap between the crank and fan using the fan belt.

[Hugh R]

Make sure the small black pieces aren't the pain in the butt internal shrouding inside the alt. that directs the air to all the cylinders