I have an '88 N/A Volvo 740, and the air conditioning compressor clutch recently crapped out on me. I want to know more about what to do now, and neither the Haynes nor Chilton books, nor the FAQ have much to say about the clutch. I would like to know specifically how to go about changing the clutch, and whether it is better to get a new one or a junkyard one. Also, as long as I'm messing with the A/C system, is there anything else particular I could or should be doing? Some old guy in my neighborhood recommended that as long as I was hanging the clutch, I ought to go ahead and replace the whole compressor. I assume that this is a pretty drastic approach, but what exactly would make sense? A project I've been meaning to get to for a while is the conversion of the system to R134a; should I go ahead and do that now? I read in the FAQ about the problems of the Diesel Kiki type compressors. How can I tell which brand of compressor my car has? If I have the Diesel Kiki one, should I replace it? What about the variable orifice valve thing? Should I put one in? I appreciate your advice and help with all of these questions.