Auto Air Conditioning & Heater Repair: AC Compressor, r134a refrigerant, reed valves

Question
I have a 94 GMC K/1500 Extended Cab Pickup with R134a refrigerant , the a/c works fine , however there is a growling or rumbling noise when the a/c is on , not present with a/c off. If I am to replace the compressor how can I evacuate the system? I know just cracking loose a fitting and letting it leak out isn't recommended but it may be my only choice. The service garage wants about $700 to evacuate , remove /replace compressor , and replace refrigerant. I am capable of doing most repairs myself.  

Answer
Are you POSITIVE that the compressor is at fault ?. What are your LOW and HIGH side pressures reading and are the readings erratic ?. Be POSITIVE of your diagnosis before doing anything.

If the compressor is starting to come apart internally you will need to remove the:

compressor.

orifice tube/expansion valve.

accumulator.


Then:

Flush out all the lines, evap and condensor with a flushing agent.

Add the proper amount of refrigerant oil back into the system after the flush procedure.

replace the compressor,orifice tube/expansion valve and accumulator.

Evacuate the system with a vacuum pump.

recharge the system.


If you leave one small piece of debris from a compressor in the system it will get stuck either in the reed valves of the new compressor or in the orifice tube/expansion valve and your system will not function properly.

accumulator.