[rbowman]

Ok, replaced the compressor,drier and orifs tube. Added oil and vacuumed out the system and added 2.75 of R134. Have cold air coming out of the ducts, here's the problem, there's a noise coming from the clutch on the compressor. It started only with the compressor clutch was disengaged but now it happens with it engaged also. it sounds like a scraping sound. I blew air around the compressor and it helped for a little while but its started back up. Any ideas? Could it be that the belt is putting to much pressure on one side of clutch housing? it's the second compressor I have installed on the vehicle, its a R4 compressor if that helps.

[fishslayer143@yahoo.com]

your belt should be tightened til you have 1/2 inch deflection in the middle.. if you overtighten it, it can put excessive pressure on bearings.. but it usually takes some time to cause noise.. I hate to say it, but it could be a defective compressor...its rare because they are supposed to be tested. did you put some oil directly into compressor before start up?

[rbowman]

It has a little over half in slack in the belt. Put oil in the compressor, The noise seemed to be coming from the clutch housing. I replaced the compressor twice now, has less than 100 miles on it.


Ron

[Hotrod]

Can you describe the noise? Is it a ticking? whining, grinding? Could be a bearing or possibly a bad reed valve, not liklely on the reed valve unless you overcharged and sent liquid refrig thru the compressor. Compressors will make some noise while operating, a slight ticking from the reed valves slamming closed, but thats it.

I just re-read your post , scraping noise I see. Check the clutch clearance I think its 0.025". Also 2.75# of refrigerant seems high whats the R-12 charge, should be 80% for the R-134a charge. I'm leaning towards the bearing if it does it all the time.

[bpassmore]

Symptoms are too much refrigerant, the system seems to like a little around 30 ozs. 134R. The noise from the compressor (rattling) is an indication of too much 134R, also when this happens the belt starts hitting the lower rad hose shield. This sounds like the whole thing is going to pieces. The high side pressure will spike quickly with a small over load of the refrigerant and the comp will start binding.

Did you back flush the condenser? A lot of crud likes to hide in there.

Low pressure should be around 25# with the high side pressure at 2 X ambient temp + 10%. You should be able to adjust the pressure switch to get it to cycle at the lower pressure. Be sure to put a fan in front of the car, the condenser needs all the air it can get.

[rbowman]

Hotrod - Put 2 3/4 pounds R134 in the system, calls for 3 pounds of R-12. The noise gets louder the more you drive it, tried blowing air down one of the indents by the clutch housing and it will go quiet for a few seconds then starts up again. When I first started it would only do it when the A/C switch was off (almost seemed as the clutch was not fully disengaged) but now it does it all the time, but its quieter when the compressor has had time to cool down.
bpassmore - I replaced the drier, orific tube and all the O-rings, Flushed the system out twice just to be sure. The recharge system I used only reads pounds, replaced the R134 with 2 3/4 pounds as people stated you only want to use 80% of the R12. Will check the low and high pressure side when I hook it back up to the recovery system.
Fishslayer - did put 2 oz of oil in the compressor (That's what the directions called for). There is slack in the belt.
I'm starting to think the clutch does not have the sufficient clearance as it seems it doesn't want to fully disengage.

Ron

[toobroketoretire]

With the clutch turned off it should have around .015" to .025" of clearance but quite often it won't retract all the way and it'll drag a little bit. Take a knife or something similar and wedge it between the engagement surfaces then check the clearance with a feeler gauge.

On my '71 sometimes it'll retract a full .025" but not always as the retract springs are weak after being in use for 40 years.

[Hotrod]

--Take some refrigerant out , about 6-8 ozs. Its possible you trashed the compressor by over charging it. Overcharging can bend the reed valves and starve the compressor of oil. You may have to start over with another compressor, but try removing some charge first. Good luck!

And high side pressures as a rule of thumb are 2 to 2.5 X ambient temp, depending on the amount of humidity in the air. The higher the humidity the higher the multiplier (2-2.5X)

[toobroketoretire]

I can't see how the humidity can possibly affect the amount of charge as the system is totally sealed so it would be unaffected my what's going on outside. But the humidity would definitely affect the amount of "felt" cold.......................

[Hotrod]

It doesn't effect the amount of charge , it effects the operating pressure(s). Your are increasing the latent load on the system. During periods of high humidity, the system has to work harder to remove the increased latent load placed on it by the higher humidity.