Well, coming home from a long trip the other day, I noticed the volt meter peg minimum on my 93 245. Lucky for me we were only 2 blocks from home (probably used up all my luck for the next year). Broke out the DVOM and read 12.5 volts at the battery and the B+ terminal of the alternator with the engine running or not, so I suspected a bad alternator. I was concerned because the charge indicator on the dash didn't light up, so I did some investigation. With the key on, the B+ had 12.5, and the D+ had 12.0. Grounded the D+ wire to the engine and the charge light did come on, so I ruled out that circuit as a problem. I was thinking bad diode(s) due to the voltage difference at the B+ and D+, but on a whim I removed the brushes and saw they were completely worn down to the holder. I thought bad brushes would still cause the charge indicator to light? Funny thing, I had the alternator rebuilt less than 10K miles ago and installed new brushes myself. What would cause this?

Also noticed the alternator growled a bit when I spun it by hand, so I think the bearings are shot. Guess the rebuilder didn't do a good job, or I had the belt tension too tight.

I'm going to pick up another alternator and was wondering if I should spring for a new one, or buy a rebuilt one. Anyone have any advice about this?

Also, can I upgrade from the 80 amp one I have to maybe a 100 amp from a 700 or other car?