Join Date: Jan 2003
Location: Rapid City SD, Black Hills of South Dakota, Queens NY
Letting the system trip the safety switch on the high side is pretty crazy, IMO . . . . knowingly or not. Physics doesn't care about intent. That switch is set to trip at 391.5 psi, which is scary high. Combine that with very old hoses in unknown condition and you've got a potential for a Darwin Award contender. I highly discourage anyone from servicing an air conditioning system without a good foundation of the basics, and basic tools like a set of pressure gauges.
If you're just trying to drive the car as cheap as possible until it craters and don't really care about the long term affects, then what you're doing makes sense with a cheapo conversion.
Hopefully the kit does ok, but worse-case is really bad if the compressor suffers the "black death." If that happens, it contaminates the entire system with tiny tiny black aluminum flakes which are near impossible to flush out and clean completely . . . especially the condenser, evaporator, and POA valve. If that happens, the work involved goes up considerably, since you might have to pull/replace the evaporator.
Also, you said that the system was almost completely down on refrigerant. There is probably still a leak and replacing the R12 with the smaller molecule R134a is just going to make it worse.
Last edited by Roadtrip; 07-08-2016 at 09:41 AM.