Alternator Damage: Causes & Repair

Hello,
I have a bearing failure in the 120A alternator on my Golf 3 AFN. Does anyone know if it's possible to replace the bearing yourself, or if a new alternator is necessary? It's probably not the cheapest option!
Thank you.

Hi,

How does the faulty bearing manifest itself in your case? How did it start? And were there any initial symptoms?
I also know a G3 TDI with what is likely the same alternator, where the bearing has some play. The question now is how long it will last.

Regards,

Eike.

It should work. Just try it out. You don't have anything to lose.

Varianti wrote:

It should actually work. Just try it out. You have nothing to lose.

Hi.

I wouldn't necessarily consider that to be so harmless.
If the engine suddenly seizes and the belt decides to break as well, allowing the crankshaft pulley to "spin freely," then on an AFN engine, the water pump is also affected... and in my opinion, a healthy engine is worth more than "having nothing to lose."

Hello.
I don't want to downplay anything, but a completely eaten-through lime storage container is quite rare. I haven't seen one yet, at least. These things usually make quite a bit of noise while they're grinding.
'I would take that thing apart and disassemble it. You can usually get the bearings from a Bosch service center or a specialized retailer. I would also replace the regulator and its carbon brushes, and check the commutator of the rotor. If in doubt, have it professionally machined.'

'Like maniac said, that's exactly what I mean. If the battery were to fail (which is extremely unlikely), you would definitely hear it or, in the absolute worst case, you would see the red 'No Charging' light. Anyone who continues driving in that situation is to blame.'

Just unscrew it. Pull out the anchor. And replace the bearings. It was quite simple on my Audi back then. But on my old Mazda 323, it was a bit more difficult. You have to use a tiny hole and a needle to push (or hold) the carbon brushes back so you can get them over a shaft protrusion. Without this trick, it was impossible to disassemble the housing.

And if it doesn't work, you somehow put it together and get a replacement part.

Wow.
There are quite a few answers that have been collected.
So:
My bearing hasn't failed yet! It's just making a lot of noise. When we checked it initially, we were pretty sure it was the LIMA (alternator) bearing. Today, I went to a Bosch service center. They said they were pretty sure the bearing in the tensioner pulley is broken, and they've seen it happen before. We've often thought it was the LIMA, but then it turned out to be the tensioner pulley.
It would be perfectly acceptable to me, as it is significantly cheaper.
To be absolutely sure, I'll take the belt off this weekend and test it.
Thank you for the advice.
Hello.