AC Clutch problem

[HammerWerf]

Folks,

This question concerns is about the Air Conditioning on my 1984 C-20 PU. Right now it has 270,000 miles.

I am on the 4th compressor hub ( the part on the end of the compressor that engages the pully assembly ) in 3 years. The compressor is the venerable GM A-6 (black log) Failure mode has been destructive. One tore the spring arms out of the rubber ring for shock absorption, and all of them have torn the metal frame connecting the hub to the drive shaft. Last one lasted only 1 week. Others have tended to last about a year.

The engine has the V-Belt pulleys. The bottom pulley is the all steel (early 6.2 years). The belt has always been tight. The engine timing chain has been replaced with the timing gear set. The AC design is the CCOT. The rebuilder is APCOAir (RossEquipment). The clutch hub's have been installed using an installation tool, and the air gap between 0.035 - 0.045 inch . The failures happen when I'm driving between 45 - 60 mph.

Any ideas as to why the clutch hubs are failing? Any ideas or solutions to minimize this occurance? Summer's a coming, and the Central Valley can get pretty hot.

HammerWerf

[Robyn]

Normally these old style pumps run forever and a day without even a Hicup

Possibly the charge is a tad too much causing a slight lockup at speed ?????

Not sure otherwise what would be doing that.

I personally have only seen one clutch failure on the Old "Log" and it was a coil failure and the thing just stopped working.

About the only thing that can destroy the clutch is a failure of the pump to start turning when the clutch engages.

Possibly the compressor has other issues???

Robyn

[rustyk]

This is only a WAG, but take a look at the crankshaft damper.