Astroman,

I live in S. Texas where A/C's earn their keep. I have a 115 300D that I was talking to an AC parts man about converting to 134. Everyone tells me that I MUST change the compressor. This guy said that the York piston comp. I have is a very good comp and not to change it. He said that the reason that comps. fail after being converted is that no one changes the condensor and there in lies the rub, as they say in the classics.

Apparently the 134 system generates more heat than the system can handle and if the condensor is not changed to a mulit-tube cross flow type the system just over heats and the comp. goes. He recommend installing as large a condensor as I can get in front of the radiator, new hoses, a new expansion valve, and a new drier. He said to seal around the condensor so that all the air that goes through the radiator has to go through the condensor.

After all this I don't know that it might not be as cheap to clean out the old system and maintain it on r-12.