Kaiserbud,
I have used HFC Environmentally safe auto refrigerant that can be used as a drop in replacement for R12 and R134,it is called Duracool, it takes half the amount than regular refrigerants and works just as good if not better than R12.This a substitude for both refrigerants, without doing any modification to the current system.
I have bought this from a supplier at the Pomona auto swap meet here in Southern Ca,probably one of
the largest in the nation,the guy is a reputable
vendor and knowledgeable with Auto A/C systems.
I had a small leak in my system and used one of his other products(Proseal)to seal a leak in the condenser. Both of his products have worked well for me and have saved alot of labor and money.
Other products include,stopleak,prodry,system tune-up,dye charge,oil charge,and oil analyzer.
Ask him for his special offer,and pick his brain he may be able to help you solve your current problem.
If interested
Dan Williams
2005 Palo Verde Ave., #188
Long Beach Ca 90815
(562)841-0932
danwilliams@JGALT.US
Rod