This is a '92 Accord LX with 200k miles. The alternator brushes are worn past their service limit (original OEM Denso alternator), and I am getting new ones. I have noticed that the old brushes wore grooves into the slip rings. The grooves are deep enought to catch a fingernail. I tried it, but I can't "just sand them off" that easily. Should this be of any concern?

The factory service manual doesn't say anything about the slip ring wear. It only mentions the continuity between the slip rings, and everything checks out ok.

Should I let these grooves be, or try sanding them off? Anyone knows how thick those slip rings are?

 

If the commutator isn't worn that much just put new brushes in it. I rebrushed an alternator in a car of mine 3 or 4 times before I got rid of the car.