My '88 420SEL (60K miles) was converted to R134 freon by the previous owner. Last summer, the A/C was weak (almost non-existent in 100 degree weather) - this year it's even worse. It occaisionally blows cold at highway speeds if its less than 70 degrees out. I'm guessing there may be a leak, however it is my intention to convert the system back to R12 freon, which one can purchase for about $20/lb on ebay these days. Although many shops recommend using R134, I'm tired of sweating in the summer and would prefer to spend the extra money to do the job right (using the refrigerant that system was designed for).

So far, I've learned that the filter/drier and expansion valve must be changed and the entire system should be flushed or cleaned out to remove any traces of R134 oil. Does the compressor need to be replaced, or removed for cleaning? Can anyone give me some insight on exactly what should be done in order to ensure my efforts are succuessful?
Thanks.

__________________
2003 S500 Black/Charcoal
1990 560SEL 61k Arctic White/Grey

SOLD:
1988 420SEL Black/Palomino Sold @ 85k
1987 420SEL Midnight Blue/Grey
1986 420SEL Diamond Blue/Grey
1983 380SEL Champagne/Palomino