1972 AC compressor issue - ideas anyone?

[Christopher R.]

i recently reinstalled my AC compressor to my vette as my restoration nears completion. I vacuumed the system, fired up the car and charged the AC based on the R134 conversion table. i have two issues: How many ounces of R134 would a 1972 vette take to be fully charged. I have good pressure on low side and high side, but i want to be sure. The good news is that after 4 years of being out of the car, everything works and it blows ice cold. The not so good news is that when you turn off the AC, the compressor clutch seems to be sticking and rotates slightly all the time. then if you drive the car under load, it smokes - so clearly this is not good. Any ideas why that is and what i can do to resolve the problem? The compressor is original, worked fine when i took it out, and was not rebuilt.

Thanks!

[Harry S.]

Re: 1972 AC compressor issue - ideas anyone?

Chris, as I recall you need 3 lbs of R134 vs 3.5 lbs of R12.

On the compressor contact Dom Tallarita. He is at dtallarita1@aol.com Dom is an NCRS member and will probably see your post. He is an expert on these compressors. He restored 3 for our chapter members, one being mine. All work great and blow 20 degrees or more below ambient.

[Mark E.]

Re: 1972 AC compressor issue - ideas anyone?

Does the clutch disengage properly if its electrical connection is unplugged?

[Christopher R.]

Re: 1972 AC compressor issue - ideas anyone?

yes, it disengages but slowly rotates with the normal engine speed, never see that before, and then it starts to smoke, almost like it is sticking/binding?

[Mark E.]

Re: 1972 AC compressor issue - ideas anyone?

So it sounds like you're saying unplugging the connection makes no difference. That eliminates the electrical circuit as the problem.

With the engine off and belt removed, what happens when the pulley is spun by hand while holding the clutch stationary?

[Domenic T.]

Re: 1972 AC compressor issue - ideas anyone?

Christofer,
Might be a easy fix. Measure the distance between the pulley and hub clutch. Use a feeler gauge to do so. The range is .022 at the closest point and not to exceed .056 at the farthest point. The measurement will vary as you measure around the clutch to pulley. My guess is that you are to close at one point which can be easily adjusted. Bad news is that if the compressor was dropped on the clutch it bends the main shaft. If your inspection of the clutch shows no damage from a drop then get a hub/clutch remover and remove the 9/16 nut that holds the clutch in place and pull the hub out to get the distance I described. If you pull it out to much then it needs to be PULLED back in with a special puller. If it is tapped in with a hammer it WILL damage the thrust bearings. If you need to pull the hub/clutch out then check the distance again after you secure the 9/16 nut to make sure it did not pull the hub back to where it was. If it pulls the hub back to where it was then a special shim will be needed that has to be made.
1- check the hub for drop damage
2- check the distance and adjust
3- put nut back on and check distance again
4- if distance returns to where it was call me: (760) 831-2095

Dom

[Christopher R.]

Re: 1972 AC compressor issue - ideas anyone?

thanks for the helpful advice. I will definitely check that out. It worked fine before we took the car apart, perhaps something happened while it was stored away all that time.

[Mark E.]

Re: 1972 AC compressor issue - ideas anyone?

Good luck. Let us know what you find.

[Christopher R.]

Re: 1972 AC compressor issue - ideas anyone?

checked everything, followed your instructions and it worked. Thanks. Everything works as it should and no rubbing, no smoke under high rpms and the clutch cycles on and off with no restrictions. Thanks again.