I have a 95 940 . I tried charging the ac with the cans. It worked for a little while and the compressor was on and off a lot. I could hear a hissing like a leak. So I took it to the dealer . They are saying I need to replace the Accumulator and condenser?? $600 in parts and $500 in labor. this sounds excessive to me. I want to save the labor and do it myself. Do I need special tools? Has anyone replaced these parts themselves?