I'm in the middle of diagnosing my AC. 1971 Skylark 350 2bbl factory AC with what looks like all factory or direct replacement. It was converted to 134a a long time ago. I believe my expansion valve is faulty. I got one off of amazon with a dryer. I went to replace them and every nut and connector is seized to the point that I twisted a pipe and cracked it. Yes, I tried chemicals also but it wouldn't work. Now, I'm thinking new lines for my ride. They look like almost $450 for the 3 (I believe) I need to replace. OR, should I just buy the crimper and get a universal kit off Vintage air and do it myself? I am curious if I can replace the hard line (dryer to expansion valve) with the appropriate "hose"? Or do I need the hard lines for the AC to properly function? And what is the "muffler" about? Its located right after the compressor but before the condenser? Its installed in my car and its in the service manual but I don't know if I can delete it? What is it for?
I plan to make my own hoses. Be sure your expansion valve is calibrated for R134, if it doesn't specify that , it probably isn't. You can make an R12 expansion valve work for R134 by counting the turns as you crank the adjustment in, divide that number by 2 and set it there for 134. If it's 10 turns for R12 it should be 5 turns for R134. It's a good idea to flush the system when doing a conversion, you don't know if the previous person did this. They sell solvent on Ebay for doing this. The muffler is to kill compressor noise, it doesn't hurt anything, has no moving parts inside, don't worry about it.
