Bosch Alternator - Brushes Squeaking
 

I've been trying to track down an annoying squeak from my car for about 6 months. I finally narrowed it down to the alternator.

This afternoon, I removed the alternator from the car and spun it by hand. It squeaked from the back. I figured the bearing was bad, but then I removed the voltage regulator & brush assembly from it, and the squeak stopped!

The voltage regulator is only a couple of years old (I replaced it in March '05). When I replaced it, I kept the old one. So, just to see what would happen, I installed the original regulator. It doesn't squeak. Then I put the new one back in. It definitely squeaks. I repeated this about 5 more times just to confirm that the brushes on the new voltage regulator were the cause of the squeak.

As a final test, I left the old regulator on and reinstalled the alternator back in the car. Sure enough, no more squeak!

While I'm very happy that the squeak is gone, the brushes on the old regulator are almost worn out so this isn't a permanent fix. I'm hesitant to buy a new regulator in case it squeaks too.

Is there something I can do about the squeaking brushes? Has anyone else had the same problem?

You could gently file/rough up off the surface of the brushes on the new regulator so it "Sets" again on the rings again. Maybe it won't squeak.

Go to an electrical automotive or even an appliance rebuilder and get them to supply you a set of brushes of suitable size and spring. They'll be very expensive,(maybe $2.00) and install them in your old or new regulator. Give it a try. If you're up to remonign and replacing the regulator as often as you've done you can certainly manage this. Take your remaining regulator and fit it up similarily and hold for a spare.

If you do decide to buy a new V-Regulator spend the extra little bit of cash to get a Bosch don't go cheap on strategic parts. For instance things like Glow plugs Bosch---'No Brainer' !

Join the club.

Turn off the headlights.:o

you could upgrade your alternator to an 80 amp or to the 115 from a saab 900...