Howdy, My alternator is screaming like a freaking roots 6-71 lung right now, and I've heard of people greasing the bearings on the alternator to stop the noise. Has anybody done this? Would you be able to tell me: 1)What kind of grease to use, and most importantly; 2)where to put the grease. I don't want to accidentally put grease somewhere where it doesn't belong. I don't know a whole lot about vehicle charging systems, but I'm guessing some grease on the brushes, or electrical connections would be a BAD idea. TIA for your help.

well theres two bushings in the alt, one in the front and one in the rear. I've greased them a couple times, but i cant say i ever noticed a difference. The bushing do have oil impregnated in them after all. I personally like to use dielectric silicon grease.

If your alt is making that much noise, i'd say that the bushings may be worn down completly.

But disasembling the alt is fairly obvious how to do if you take a good look at it.

OK so 2 sets of bearings, cool. Dielectric grease, no prob, I think I have some lying around in my tool box.

Do I have to remove anything from the case to get access to the bearings? Are the bearings sealed?

Thanks lots for your help.

you just have to take the case apart, the rear half of the case just comes all the way off, so the rear bushing is easy to get at.

The front bushing will be harder to get at, unless you take the pulley off. But i'd just put some grease on the communtator shaft and move it back and forth into the bushing....

It'll make sense when you get it apart....

Perfect, thanks man.

The bearings are sealed ball bearings, they are NOT greaseable, if they are noisy enough to make noise they are toast, replace them, however if the alternator sounds like a supercharger often it's the diodes that have gone out, that makes a loud whining noise and will cause the unit to heat up VERY fast, but it will go away if you unplug the connector in the back, if it's still noisy after unplugging the connector then the bearings are bad.

1. The front bearing is a ball bearing. They can be cleaned and regreased, but that size isn't worth the effort. A new 203 bearing is about five bucks, and you'd have to disassemble he fan/sheave from the shaft in either case.

2. The rear bearing is a cylindrical roller, and can be cleaned and regrease if the hardened shaft and outer races aren't scored.

3. Dielectric grease has no effective lubrication properties for an antifriction bearing. It lacks adequate film strength to lubricate the rollers. Use an EP 2 or RP 1 grease.

4. Dart may very well be right. If you have a "whine", it could just as easily be electrical noise as menchanical noise. Obviously, he's been around this track once or twice already.

Thanks Vader/Dart.

So basically you guys are suggesting a rebuild, or at the very least, new bearings.

I will look into rebuild kits, thanks a lot guys!