kmascotto

So can you see the problem??...Three times I've had to flip the AC belt over, after finding it as you see in this picture...WTF. I can't believe it actually would ride on its back and stay put...
I am hoping my belt choice was the issue. I replaced all the belts when I did the WP/TB job...and I think I ordered the wrong belt (99919230550)
In 88/89 there was a change in belts for the CS/GT (637/639 codes) A/C compressor pulleys. It appears they used a narrow belt. 99919233550

I hope this will fix the issue

Leon Speed

Now there is something you don't see every day.

MainePorsche

Indeed.
That's a first.

Ducman82

How odd! To fat and to long?

kmascotto

Here is the belt I was using (99919230550)=Narrow V-Belt 12,5 X 1125

This is the belt I believe I need to use (99919233550)=Narrow V-Belt 12,5 X 1080

I think they are the very similar, the belt I was using is a little longer, but it was well within range of being tight.

I think it may need to be a sharper V than the belt I was using, to run in the pulley with out walking out.

Funny thing, my compressor looks different than the compressor on the GT/639 code. based on the system for adjusting the slides on the compressor, its identical to the 1989 compressor...maybe its just the pulley that's different.

Mrmerlin

I am going to go out on a limb here and say that your compressor is getting ready to fail,
the reason the belts jumping is that the compressor is locking up instantaneously ,
and then the belt of course pops off the pulley due to the sudden stoppage

kmascotto

Thanks, what would cause the compressor to lock up?

Mrmerlin

could be the wrong oils got mixed,
too much oil ,
not enough oil.
overpressure of a component
blocked expansion valve,
the compressor could be seizing .

IIRC Bill Ball had a similar issue a few years back cept his belt kept popping off the compressor

19psi

Had that happen once on my Corvette after installing an aftermarket compressor bracket due to headers. I just needed to shim it out a bit to align the pulleys better.

My Corvair would always do that if I didn't use a wrapped belt that was adjusted just right...then again that was an odd beast in that the belt made a 90º bend from the front of the engine to the top so things needed to be perfect.

Personally, I'd make sure the pulleys are tight/aligned and toss a new belt on it.

kmascotto

Thanks for the clarification if it happens after the new belt is installed it could be time for a compressor rebuild

Mrmerlin

More info after some searching from Bill Ball.

https://rennlist.com/forums/928-foru...2FC+compressor