I noticed the belts would squeak above 4000rpm. So I checked the alternator, and it seemed a little crooked. Bushings. Common problem with the OEM rubber units. So I bought some circlip pliers, got new urethane bushings, and set off to do it last night. Got the alternator off. Noticed that the pivot bolt was WORN down into an odd shape, and it was about 1/2 its original diameter. It didn't break! Examined the alternator, and noticed that the steel sleeve inside the rubber was partially hogged out. Sh*t. Took off the bracket from the engine, and found the front hole looked like it was double wide, the rear hole was "L" shaped. Went to the Sears Hardware store, got a couple new bolts, 7mm and 8mm washers, and an Oxy-MAPP brazing kit. I brazed two 7mm washers onto each bracket flange. That took about 30 minutes. Since they were a 7mm hole for 8mm bolts, I used a 5/16 drill bit to ream them out. The 8mm bolt shaft fit perfectly. Bolted everything back up, cleaned up, and took it for a spin. No more belt squeak, and I'm not worried that my belt will get shredded while on the beltway or stuck in traffic. Yes, I'm ordering NEW parts from the dealer to fix it.
This happened to my friend at Roebling. His bolt actually broke. Twice in the same weekend. This has also happened to others, I'm assuming. Has anyone done anything to make the factory mounts better so this bolt breaking/hole reaming doesn't happen anymore? I was thinking you could drill the flange holes and sleeve out to fit an M10 bolt (17mm head). This may be a little complicated, but I'd imagine that it would probably be worth it.
88 M3 Henna