This is a picture of a 1979 parts truck, with a 302, air compressor that I acquired. It has a complete air-conditioning system. I plan to take it out of the 79 and put it into my 1977 project truck with a 302. I did a lot of research on the system and I wanted to get it working prior to installing it in my project truck.





The parts truck had no belt and the valves at the hoses had been cracked open to release the refrigerant when I bought it. I purchased the high and low adapters from R-12 to 134A. The adapter for the low needed to be a 90 degree adapter because of the way the service valves are located next to each other.


I rented it vacuum pump and evacuated the system. When I was done, after 1.5 hours, they both are showing negative pressure.


Next, I started the truck and introduced 134A. The service valves were open, but not sure how much due to the design. I threaded in the service valves from the gauge set so the refrigerant could enter the system. I stopped filling when I saw both high and low gauges we're reading 75. I know that is high for the low side. I have read that if they both read the same, that means the compressor is bad.


I have not checked the oil in the compressor yet, but will do so. That is my next step.


The compressor clutch does engage.


Can anyone tell me if they think my compressor might be bad? Or am I doing something wrong, which clearly could be the case.


Any help is appreciated. I have read the service manuals and have combed through the forums.


Thank You

 

Was the clutch engaged and turning when you took the pressures? Be sure to run compressor with both valves backed fully out. A few turns in will let you charge and test system.

 

Yes it was engaged

 

How much freon did you get in it? Where the valves seated all the way in? They are supposed to be out. The suction line should get cool or cold if compressor is working.

 

The service valve on the compressor was about halfway. I thought that was where it was supposed to be.


I don't know how much went in. The can was about 18 oz. I did not use it all. I think the hoses were hot not cold, I would need to take better notes next time.

 

With engine off, grab the clutch, not the pulley and see if it will turn, it should feel like it has compression in some spots. Valves halfway will work. The orfice tube may be plugged and not letting it pull a vacuum on suction side.

 

I took off the belt, Engine off and turned the pulley and the wheel. no resistance at all. Also no oil. So the next question. Do I try to put oil in it or should I look into rebuilding the compressor?


Thanks

 

Never heard of anyone rebuilding one. Most people just get a replacement. Wouldn't think it would be to hard if you can find all the parts. Supposed to be a piston style pump but never had one apart.

You did turn the clutch part on the front of the pulley, correct. The pulley will free wheel with the belt off. The clutch face is the part that is hooked to the pump.

 

With the belt off, I can spin both fairly easy. I do not feel much friction on the clutch, not enough that I think it is working properly. I may try to disconnect the service valves and see if it pumps any air. I am not sure if that will prove anything. I hate to replace it if it working fine..


Thanks for the help

 

From your description (especially the no oil part) it sounds like the compressor is bad.
With the belt off and the ignition "off", you should be able to spin the pulley easily. When the pulley spins, look at the center of the assembly, that shouldn't be spinning. Now turn the ignition switch "on" and try spinning the pulley again. This time the center should also turn and you should feel resistance. If the center still doesn't turn then you probably have an electrical problem (clutch not engaging). If the center does turn then, if the compressor is good, you should be able to charge the system. If the compressor is bad, it's usually because they've thrown a rod, so I would expect to hear some bad noises coming from the unit. On occasion there's a problem with the valves that will keep the compressor from working.
If the compressor turns out to be bad, consider a Sanden conversion. The compressor is lighter, quieter, more efficient, smoother running than the York. The kicker is a NEW Sanden style with clutch is usually cheaper than a REBUILT York without the clutch.
It's a fairly simple process.

 

Anytime. Bruce

 

THANKS MIKE,


With the belt off and the ignition "off", you should be able to spin the pulley easily. When the pulley spins, look at the center of the assembly, that shouldn't be spinning. THIS PROCEDURE WORKS.


Now turn the ignition switch "on" and try spinning the pulley again. This time the center should also turn and you should feel resistance. If the center still doesn't turn then you probably have an electrical problem (clutch not engaging). If the center does turn then, if the compressor is good, you should be able to charge the system. THE CENTER DOES SPIN WHEN TURNED ON.


If the compressor is bad, it's usually because they've thrown a rod, so I would expect to hear some bad noises coming from the unit. On occasion there's a problem with the valves that will keep the compressor from working. I HEAR A NOISE THAT SEEMS LIKE A PISTON IS MOVING, CONSTANT NOISE REPEATING. NOT LIKE SOMETHING IS BROKEN. ALMOST LIKE THE PISTON (IF THATS WHAT IS INSIDE) HAS NO RINGS.

If the compressor turns out to be bad, consider a Sanden conversion. The compressor is lighter, quieter, more efficient, smoother running than the York. The kicker is a NEW Sanden style with clutch is usually cheaper than a REBUILT York without the clutch. I HAVE READ ALL ABOUT THIS.


I AM NOT SURE IF IT MAKE SENSE TO BUY THE OIL. ALMOST LIKE THOWING GOOD MONEY AFTER BAD.


I WILL REPORT BACK

 

If your tear one of these Yorks apart, the short block looks like a two cylinder engine. It has a crank, rods, pistons and rings.

 

I have another compressor that I am going to try. Then I plan on taking the other apart and look.

Thanks mike

 

I'm a little confused when you say both valves were open I'm assuming while charging? I haven't messed with any AC trucks like these but have done many newer cars.

How much did it cost you to rent a vacuum pump? My buddy and I both have the one that Horrible freight sells. I don't normally shop there but for the money it's actually a good product for the money. After you pulled the system down to 30" did you check to see how long it would hold it? Did you just introduce the freon into the low side to get the compressor to kick on?