I am the 2nd owner of this 86 300E so I'm not sure if this alternator is the orginal one that came w/the car. Although I'm pretty sure it is.
The car runs fine whether all the indicator lights are on of off. BUT I do notice lack of electricity to my radio and lights when all the indicator lights are on (from the battery to the ABS)
I put in a new OVP (behind the battery) a few months back.
The brushes were both shiny w/grooves on the surface. The brushes were worn down unevenly. One was maybe 3/4 of an inch long and the other was about 1/2 an inch long. The shorter one was closer to the diode.
The diode was very dirty with black debris/grease (or something). It kinda looked shorted out. I was going to install a new one, but it cost somethng like $80 here in Hawaii. So I just cleaned out the orginal one. When I tested the car the other day (after reinstalling the cleaned up regulator) all the indicator lights flickered on twice. At present, all the indicator lights are off and the car runs fine. I'm just afraid that this is a temporary fix. I'd hate to get stuck somewhere. Right now the car is home and I can easily replace the alternator or the regulator if needed. I'm tempted to take a chance on a new regulator (vs getting another alternator). Where can I get it for $25 as someone said it cost?
Thanks to everyone who are replying. Your input is helping out a lot of people. I'm sure I'm not the only one with this problem.
1986 Gold 300E 4Dr automatic