Does anybody know what would cause an ac clutch not to spin. It is full of R134 and the clutch spins freely by hand when the engine is off.

Thanks,
Hunter

 

First thing to check is the air gap in the clutch. If it to big then remove the center bolt and a shim. Replace the bolt. Try again. Then you can get into circuit testing etc.

 

usually a clutch not turning when you have switch set to s/c means either the magnet is shot in the clutch (not likely but easily replaced) or the signal isn't getting to the clutch (most likely) or the compressor is seized (likely but not most likely)

EDIT: although you have a 1990... original compressor? I think you have a single wire going to the clutch... check voltage signal... easier than removing the belt and playing with the clutch.

EDIT 2: The clutch spins freely or the pulley spins freely? There should be a resistance when spinning the clutch.

 

Thanks for the replies, but you can call off the dogs. I found the problem. I had checked pressure with the engine off, but after checking it with the engine running the pressure was fluctuating badly. Then, I spotted an obvious problem...split hose on the high side...within a few seconds it was spewing smokey vapor everywhere. I guess I just need a new hose.

Thanks,
Hunter

 

Yeap there's a pressure switch in the system that will save your compressor if the R12 or R34 pressure is low or a hose breaks.