I’ve read through several threads and searched but haven’t seen anyone address how to handle the changing the A/C from R-12 to R-134. When disconnecting the A/C do you have to discharge the system a particular way or at a shop? Do all of the 3rd gen parts swap over if you’re using the 4th gen compressor? I’m assuming mine is still R-12 even though it’s blowing cold. Thanks

Slice

 

You can find a wealth of information about the R12/ R134 conversion on the cooling board of this site.

No 3rd gen parts will match the 4th gen compressor.

Don't discharge your system into the atmosphere, take it to a shop.

 

Take it to a shop and have them discharge it and flush the system. The oils between r12 and r134 isn't compatible and will turn to sludge if you mix them.

If you use a top mount ac bracket you can find one that works with a 3ed gen style compressor and run r12, if you keep the 4th gen compressor in the low mount position it will have r134 oil (PAG) in it and I would choose to run r134 in the system. While you are at it if you replace the condenser with the 91/92 model it works better with the the 4th gen compressor. You will want to replace the dryer and expansion tube also. I would also re o-ring the system the r134 o rings are a different material than the r12 (the r134 are green, r12 are black).

People have ran all the 4th gen parts but they don't quite fit.

I ended up replacing 100% of my AC system with my swap, the only used part was the hard lines to the compressor from the 4th gen donor, I took those to a hydraulic shop and had them reworked to fit the thirdgen.