Fan Belt Problems

[JIM KELLER]

Prior to our trip to POG III in Kerrville I noticed some missing teeth on two of my belts. I replaced them and all other belts at the same time. After our return a belt inspection revealed the same two belts were missing some of the teeth again. All other belts without teeth are fine. These two belts go around the harmonic balancer and then the alternator and over the road a.c. compressor. The belts are AX74, 1/2 x 76'' long. I am considering A74 belts this time which are the same size and width without the notches or "teeth."

My question is, why are these two belts the only belts on the bus with notches and why are they the only belts having a problem. It was always my understanding notched belts were designed to go around small diameter pulleys so there was less stress on the belts. None of the pulleys on our engines are small so I am wondering why notched belts are being used in this application.

Anyone have any ideas why Im losing my "teeth" ?

[dale farley]

Jim, The most logical solution for losing teeth would normally seem to be "Old Age", but since you said you just replaced the belts, maybe that is not the problem this time.

I too, find it strange that you are losing teeth on two belts. Have you checked to see if there is a small imperfection in the pully (a raised piece of metal, etc.) that may be tearing the belt? Not likely if you have two different ones doing the same thing, but this is strange.

[win42]

Jim: I would inspect the pulleys as dale suggested first. Then measure all the pulley sizes and call Gates Rubber in Denver and run it by their engineering.

[JIM KELLER]

Jim, The most logical solution for losing teeth would normally seem to be "Old Age", but since you said you just replaced the belts, maybe that is not the problem this time.

I too, find it strange that you are losing teeth on two belts. Have you checked to see if there is a small imperfection in the pully (a raised piece of metal, etc.) that may be tearing the belt? Not likely if you have two different ones doing the same thing, but this is strange.

Dale, Thanks for the input. I have checked the pulleys and they look o.k. There could be a slight miss-alignment of the A.C. Compressor but it is hard to get my head in alignment with the belts to be sure. If so it is very slight. Guess I will wait for "JON" to step up and comment on this problem.

[JIM KELLER]

Jim: I would inspect the pulleys as dale suggested first. Then measure all the pulley sizes and call Gates Rubber in Denver and run it by their engineering.

Thanks Harry, How does your California girl like her new bus ? Did it keep her cool on the return trip ?

[Jon Wehrenberg]

FWIW my belts are without teeth.

[rfoster]

Jim K: This is a SWAG or a hunch at best. I recently experienced a terrible, terrible noise coming from my engine when I fired up the engine while in Hotlanta the other day. We had been dry camping the night before and had shut the engine off with the OTR bus air still on. Due to the air regulator leak over the engine door my belt air bags (bellows) loose their air pressure overnite. As a result the air was down in the bellows that tighten the belts and the bus air was on so when I fired up the engine the belts were not exactly slipping but skipping on the pulleys making a terrible noise. jerking, and possibly knocking off some teeth. I immediately shut off the engine and a/c and inspected the belts and yes they were too loose. I fired the motor again with a/c off and let the air build in the bellows and then all was well. I since ordered a new regulator and three new bellows from prevost (on Sale for 25 lewbucks each). Will install this weekend. Check it out on yours and see if the belts are tight from a cold start. This is still no answer as to why the a/c belts have teeth. I even bought new ones with teeth for spares. I would still like to know whey they have teeth.

[lewpopp]

While were on the belt subject, the belt that goes to my dash air is presently useless because I was told my compressor was shot. Is there any reason I need to run the compressor with that belt? I'd like to cut the belt and go from there until I replace the compressor.

Also, someone said I can replace that compressor with a compressor off of an old Ford pickup. Does that sound right? Before I did that I would make sure the lines running forward were without leaks.

Lew

[dale farley]

Lew, If I were you and the compressor wasn't working, I would definitely remove the belt. No use in turning it for nothing.

If your compressor is like mine, it does look very similar to other compressors I've had on vans in the past. I would think that any compressor that you can make fit the spot would work. I would also convert it to 134A (or later version) freon when I replaced it.

[garyde]

I still have most all of my teeth.....and my fan belt does not have any.