V-Belts

[upnorth]

I am having a bit of a problem with one of the v-belts on my motor home. It is a 1984 chevy chassis with the 454. It keeps tearing up and throwing the belt that drives the water pump, air pump and the alternator.

Started out that it blew the belt so I just popped a new one on and found the alternator had a stripped screw hole, but I figured I could tighten it down enough to make it home, well it made it about ten miles. so I replaced the alternator, the pulley did look a bit worn one one side too) put it all back together and ran it for about an hour and it seemed to be fine so off we went for a short trip. Made it to the campground and no problems but on the way home it popped off again. It didn't break, but it is somewhat twisted and it looks like it kinda slipped over sideways(yes I made sure it was on correctly). What should I be looking for? All the components seem to be working fine until it throws the belt.

Anyone got any ideas?

[PierBridge]

Tensioner Problem?

[upnorth]

There is no tensioner. I let it run for about 10 minutes and re tensioned the belt.

[Macgyver55]

Any strange noises involved with it??

Check the air pump...I've run across a few over the years that intermittently catch and/or lock up. Pull the belt off and turn it by hand, you should be able to feel if there is any problem. Don't forget to check for anything that may be accidently rubbing on the belt. Check all the pulleys for alignment ....possibly one of them is out of alignment from a broken mount on the air pump or power steering pump. Also, check the dampener pulley on the crankshaft. Could be the rubber section is starting to fail causing it to wobble. Should be able to see if you watch it while idling.

[jps]

I have had a pully bend if the belt broke and did a wrap around!! jps

[upnorth]

No there are no strange noises. I ran the motor for quite a while with the cover off just looking and listening for anything weird, but didn't hear or see anything that really triggered anything. I did turn the air pump a little and that seemed to turn free, but I really didn't focus on it. I ran a straight edge along the sides of the pulleys and that seemed pretty good. I think I need to get in there and really check on those pulleys. The more I think about this from the way it seems to have turned the belts on their side, I am thinking one or more is warn too much on one side. I wish I could have seen what it looked like just before the belt came off. I hope I can just replace the pulleys or this may get pricey

I am still open to any ideas here.

[upnorth]

Took a while to get the thing out on the road after changing the pulley on the air pump. It runs fine in the driveway, ran it for about an hour or so the re-adjusted the tension, no problems. But after a about 10 miles on the highway it lost the belt again. It seems to wear the bottom of the belt off then it comes off. I did turn the air pump by hand and that seems fine, could be that it fails at higher speeds only? I can't see anything out of the ordinary on the other pulleys and v-belts and I did replace all 3 belts and the alternator is new.

This thing ran fine for the 3 years since I got it and all of a sudden it is puking belts after a very short period of time. I have replace the belt 3 times and it is the same thing everytime.

Has anyone ever run accross anything like this? I am really thinking of replacing the air pump, but this replace this and then than is getting to be rather expensive.

[cold one sd]

The samd thing happened to a friend and it turned out to be the dampener on the crankshaft.

[IFallsRon]

Sounds like something is wearing out and causing drag on the belt. They react a lot differently under load than when you're watching in the driveway.

I most recently had an alternator go out. It made random noise and from experience I knew it was going. Oddly, it was registering fine on the meter but when I took it off it wouldn't turn freely.

Try taking a ruler or something long enough to stretch across your pulleys to see if they are running straight. If you're not getting a flat plane from one to the next, you may have located the problem.

[upnorth]

I have checked alignment and that looks good. The only thing on this belt is the alternator, the air pump, the crankshaft and the fan. I have changed the alternator, and replaced the pulley on the air pump, cuz that was worn pretty badly as was the alternator pulley.

How can one check the crankshaft damper. Looking at if from above it looks to be running true. There are 2 other belts running off different pulleys on the cranks shaft and they seem to be fine.

Is there a chance the I am tightening the belts too much? I have always just tightened as tight as I could in the past and never had them fail.

[pfluemis]

Check end play on the water pump, air pump, and alt.

Check for lobing pulley's.

Check for damage and/or odd wear on all pulley's.

Double check to make sure you have the right width belt.

Dry/bad bearings are more likely to show problems when hot. Drive down a low traffic road until the belt falls off. Stop ASAP and check to see if anything is sticking when hot. My thought is the bearings on the air pump are dry, heating up, expanding, and causing the shaft/pulley to become very hard to turn. This would be where your belt wear and rolling belt symptoms would come from.

[IFallsRon]

I was researching something else and found that the harmonic balancer, if applicable, could be the problem.