Last time I did one was many many years ago I removed all the r-12 took the compressor off drained the oil flashed the whole system put new peg oil in the compressor and pulled vac and recharged with 134 and that puppy was cold. I had that truck for about 5 year before i sold it and never had any problems with it. I am not a ac guy but this is what my dad told me to do it.
