R134 to R12 (de)conversion
 

I've been reading myself half to death about this topic. I am ready to undertake this, but I have one last question. I've seen mentioned a number of times that part of a conversion should be changing o rings. Why is this necessary?

Thanks,

Mark

If your oil isn't compatible with R12, you need to flush the system. Putting it back together again will require new o-rings.

If your oil is compatible, I see no reason to flush the system or replace any o-rings that aren't leaking. The new, green HBNR o-rings are fine for R12.