I see folks write now and then, almost in pride, that they are able to change the regulator/brush pack with the alternator on the car; in situ so to speak. I'm guilty too. It used to be a lot easier when the retaining screws were slotted, but since Bosch chose to use Phillips on the newer alternators, the screw heads don't always fare so well.

But, the relevance is here: If the brush pack gets swapped on the car with the belts on, the slip rings cannot be inspected very well. Those with eagle eyes may be able to spot a set needing care, but in general, if your eyes are as old as those alternator cores, it isn't likely you've checked out the slip rings.

A stopgap shortcut, where the belts are off, is a sort of fingernail runout check, perhaps following a pass with a bit of Scotchbrite, but the real deal can only be done on the bench. My guess is, as the alternators get to their 3rd or 4th set of brushes, the brushes just don't last as long.


--
Art Benstein near Baltimore

Ohm my God, that was bad. Watt made you tell that joke?