HC3 wrote:Thanks Tim and Cusser,
It looks like HNBR O-rings come in black or green.
They may not be exactly the same (e.g. different durometer)
I guess I'll assume the QD fittings for R134a will be OK.
It makes sense after all this time at least the R134a fittings should have compatible O-rings.
I might try putting some teflon tape on the threads as a belt and suspenders approach.
When was the last time you saw Teflon tape on a vehicle AC fitting? I think you're making this a bigger deal than it really is.