Originally Posted by MrCjames

I can't say that I have had the pleasure and I understand your point; however if the conversion is not performed to a certain standard-YES problems develop........IMHO overcharging a system falls into the lees than standard category.

When retrofitting R-12 to R-134 I have always followed the manufacturers written instructions (for good reason) and I have seen few failures when the instructions are followed to the T. Now contamination from mechanical failure and or the use of unusual refrigerant blends (the low cost alternative mixtures that only reek havoc in the automotive repair world-especially with recycling equipment) I will do several (6-10) of those in a year. As an extra precaution when I convert the AC system from R-12 to R-134 I always go a few steps further mainly because I am from the old school of AC repairs. I flush the condenser, the evaporator and all the lines as best as possible. When the flushing is complete I install a new expansion valve and a new receiver drier as well as new pressure switches (always). I also R&R the AC compressor-drain it and then refill it with the prescribed amount of oil (unless the comp is getting it's triennial replacement.

Regardless of what a vehicle is willing to pay for a repair their expectations for the repair to be performed well seem to always be much higher-meet and exceed their expectaions and charge accordingly simple as that