I am still on the fence about my 1990 wagon. the main concern in the keep/sell question is fixing the A/C. When I was getting the alignment done, I asked the mechanic how to test the old A/C system to see where the leak(s) are. He said he had r12 still, but would need to charge up the system and pressure test it for leaks, very expensive he said. Ok, what is a resonable way to test what issues the original r12 system to see what needs to be replaced? Thanks in advance, Greg