Can You retrofit a R12 cycling switch to a R134a?
The switch manufacturer usually presets them for the stock R-12 and some have a sealant on the screw. Just remove the small drop of sealer to turn the screw. Preset was fine when all cars where filled with R12. But when retrofitting to R134a they should be
What’s the difference between R-12 and R-134a?
Lower the adjustment of the clutch cycling switch to 21 to 22 PSI. This is because the pressure temperature relationship of R-12 and R-134a is different. For instance at 25 °F the pressure of R-12 is 24.6 PSI and the pressure of R-134a is 22.1 PSI.
What do I need to retrofit my AC to R-134a?
R-134a, adapter hose, new R-134a service port adapters, retrofit label, new schrader valves), a third 12 oz. can of R-134a (for a grand total of 40oz.), a large bore schrader valve and valve removal tool, Snap ring pliers (if replacing the compressor), safety goggles and maybe gloves, and a normal assortment of metric and standard wrenches/sockets.
How to retrofit a General Motors R134a?
For additional information refer to the General Motors “R-134a Service Manual” (MS-3644), Service Bulletin No. (43-12-07E) or phone 1-800-269-5100 and ask for brochure “GM-0011”. This is a list of GM vehicles by body style platform. GM’s test indicate that minimal changes will have to be made R12 systems to retrofit them to R134a.
The switch manufacturer usually presets them for the stock R-12 and some have a sealant on the screw. Just remove the small drop of sealer to turn the screw. Preset was fine when all cars where filled with R12. But when retrofitting to R134a they should be
Lower the adjustment of the clutch cycling switch to 21 to 22 PSI. This is because the pressure temperature relationship of R-12 and R-134a is different. For instance at 25 °F the pressure of R-12 is 24.6 PSI and the pressure of R-134a is 22.1 PSI.
R-134a, adapter hose, new R-134a service port adapters, retrofit label, new schrader valves), a third 12 oz. can of R-134a (for a grand total of 40oz.), a large bore schrader valve and valve removal tool, Snap ring pliers (if replacing the compressor), safety goggles and maybe gloves, and a normal assortment of metric and standard wrenches/sockets.
Why do I lower the clutch cycling switch to 22 psi?
I have not heard of any mention of the V5 compressor control valve, which changes the compressor displacement acording to temperature. Lower the adjustment of the clutch cycling switch to 21 to 22 PSI. This is because the pressure temperature relationship of R-12 and R-134a is different.