Hi all, my alt belt keeps snapping. Is this because the bearing in the alt is fubar or because i have it too tight ??

the alt is working fine but the pully seem's to be sticking as the the belt snaps following a burning smell

first off are you still running the smog pump? Are you actually watching the alternator seize or are you just assuming that's what's happening?

yep still running the smog pump and no i haven't actually seen the alt seize

could it be the water pump seizing ?

Do all of the pulleys line up? I mean there's nothing misaligned or anything is there? Have you turned all the accessories by hand to make sure nothing sticks?

whats the other accessories got to do with the alt belt ?? and nope there's nothing obstructing it

You tell me, you mentioned the water pump I was merely asking if that stuff was spinning freely.

Can you spin the alternator pulley when the belt is removed? Do you feel it spin smoothly or is it hard to turn?

The only time I've ever had issues shredding belts is on a seized accessory of some sort, in this case I am referring to anything driven by a belt as an accessory, it's usually pretty obvious and it lets out a pretty good squeal before it shreds.



AS far as belts just snapping, the only time I have seen that happen, without the previously mentioned symptoms is from the belt being way over tightened. SOOO, my guess would be you are either tightening the belt way to tight or the alternator is randomly locking up, which I guess is possible.

yea it spins freely and seems to be locking up randomly

Is that the result of a bad bearing and if so can it be replaced ?

You could rebuild the alternator, although it would probably be easiest just to replace it.

This is rather peculiar. I would think that an alt bearing that was bad enough to seize would seem pretty screwed up when you spun it by hand. IIRC, the alt belt touches only the alt, the water pump pulley, and the crank pulley. Is that correct? Does the water pump spin freely by hand?



How the heck tight are you getting it? I think a finger pushing on the belt midway between the alt and the crank should be able to deflect the belt at least 1/2" without really trying. Tighter than that is probably too tight. Getting the belt tighter than necessary to keep it from slipping just puts additional stress on the alt and water pump bearings (and the belt itself).

The alternator belt runs on the water pump pulley and main engine pulley. If the water pump was your problem you would also be having a problem with the air pump belt as well since they both run on that pulley. The alternator is the only thing that makes any sense that could be cauing it. Alternator bearing is about 20.00 at rockauto.com and a new alternator is 122.00 with a 60.00 dollar core. try to tighten the belt with about 1 to 2 inches of deflection.

Thanks for all the advice people. I fitted a new one (a wee bit less tight) and drove 75 miles with no probs