I just bought a 1990 245 with a non functionnig alternator because I already had a alternator with only 60 000 miles on .It was rescued ten years ago from my first 245 - a 1986 before the car was sent to the junkyard. I checked the brushes on the alternator coming out of retirement and one had a rust stain on the tip. I cleaned it with vinegar and steel wool. I took it to a car part store wich checks alternator for free and they tell me that it charges only at half capacity that is 35 amps instead of 70 .

Is there a chance that the problem is due to the rust spot and would the rust which is still there wear away once the alternator runs full speed for a few hours. I have cleaned the copper oxyde where the brush holder gets its juice from the body of the alernator.

Is there anythig else I should check before going out in the winter night with this alternator. It ran without problems before and was kept indoor in a semi heated garage except for the first four months when it sat in the wrecked car.