Noisy Alterntor Belt

[mmvette80]

I have a annoying alternator belt. Years back I had to replace the alterntor bracket. I dont know if this caused it but the belt is noisy. Ive replaced the belt and the alternator. I even mounted the bracket with washers behind it. That didnt work. No mater how tight I make the blt it squeals at 3000rpms. Any help out there? :bash

 

[Eric]

It sounds like the drive pulley and the alternator may not be alligned properly, causing side tension, hence the noise. Mine squealed at low RPMs but I replaced it with one of the newer style belts with teeth and the problem was solved.

One way to diagnose a pulley alignment problem is to feel the edges of the belt after the car has been running a while (turn the car off before trying this). If the edges feel hot or look a little frayed then that's at least part of the problem. I learned that on my 77 Cutlass - never could get it straightened out though :eyerole.

BTW, it shouldn't be too tight - about a 1/4 inch of play. Oh yeah, I dig those bowtie valve covers - sharp .

Good luck!

 

[mmvette80]

I have the new style belt. Ill have to play with the bracket again.

 

[Scott81]

I think 71Shark has something here, it could be an alignment problem. I kept having to replace my alternator once a year, thought they were just cheap rebuilds so I eventually took it to a good rebuilder and had it beefed up, sure enough it only lasted about a year. I finally figured out the problem when fixing something else, turns out that the alt bracket itself was slightly bent. Once I replaced the bracket no more problems, I would take a very close look at your alignment and how the alt rides on the bracket.

 

[mmvette80]

Im gona fish for a used bracket. The one I got is a repro.

 

[Jack]

mmvette80:
I replaced the flimsy stamped steel alt pivot bracket that was factory on my 71 sb C3 ... it bolted to water pump. I changed to a cast/forged iron/steel version from a GM pu truck ... it bolts directly to front of drivers side head & is far sturdier. However, it does not fit with the rams horn exhaust that have a boss on drivers side ex man for alt pivot bolt ... that is ... it won't fit without grinding the boss. With tube headers the truck bracket would fit w/ no problem. I think some later sb C3 came from factory with the same bracket as truck (or similar) ... & some even came with that bracket in cast aluminum.
JACK:gap