The climate control system on my '86 740 is a disaster. The heater control valve is competely missing and the core is bypassed. Since it never really gets cold in Arizona It really doesn't matter to me at this point of the season. Maybe next year. However, as summer approaches I have no desire to fry in my brick, as 115 degree temps are not uncommon here in the summer. Here is what I have. A compressor of unknown make with a two wire connector on it. One of the hose connections is disconnected at the compressor and I found that the nut is stripped. The compressor therefore has had one nipple open to dust, dirt and the elements for who knows how long. The system has beed converted to R134, but since I have a 25 lb bottle of R12 I want to go that way for better cooling. I think at the least I will have to get new hoses made, have the compressor tested for fuctionality and leaks, replace the drier and expansion valve, and evacuate and maybe flush the system. My question is do I need to change the oil in the comp. or can a 134 set up work with R12. is there anything else I should know about as I go through the system??? Any suggestions on replacement of compressors and hoses and any tips would be appreciated. In the past I had had pretty good luck just getting an older compressor tested and resealed as opposed to going with a new compressor which can be very pricey.

thanks,
740man '86 740