I have a 96 Ford Ranger. My A/C compressor has seized up and I want to remove it. I've worked on my own vehicles all my life just never worked on the A/C. My shop manual says the A/C system has to be depressurized first but doesn't tell me how. How do I do it?
You probably don't have much refrigerant in the system. Your compressor may have seized because of a leak in the system. Once you lose too much refrigerant and oil, and when there is leak, both escape, then there is nothing to lubricate the compressor and it seizes. You probably have r134a in the system, it is fairly inert, and you could release it by attaching a manifold gauge set-up and opening the low side port to the atmosphere. I don't know the laws, and do not condone releasing unknown gases into the air we all breathe. If you have an R12 system, I am positive that you can't release that, have a shop remove all R-12.
It also sounds like you need to hit the library or automotive book store for a few good books on the fundamentals of air conditioning. Most A/C systems are simple to fix, but, you can also screw up an otherwise good system by doing something wrong.
By the way.. the compressors are usually sold without the field coil and clutch assy., you will need special tools to remove those parts from the old comp. to the new one.