I have a 1960's Mark IV type A/C evap. unit I'd like to use with a Sanden compressor & R134 in my '55. Having heard the stories that 134 will leak out of hoses, etc. that are O.K. for R12, I'm wondering about the metal to metal flare fittings on this evap. & if they might seal & hold the charge. Anyone tried this experiment? Or should I just pop for a modern repro evap. that has o-ring fittings? I really like to use the old stuff when possible.
use an A6 compressor, and scare up some R12 for it. Last week I put a new fuse in the ac on my 59 chevy truck I built in the mid 90s, it blows cold, it had been sitting unused for years. It has an old underdash unit and an A6 compressor, flared fittings on the condenser, etc.
I have this exact same setup in my COE as you are describing,. I think my evap unit is even a Mk IV, it is form a mid 60's Ford product. Although I had to get new hoses made up and all new hose materials are what they call barrier hoses which have lower leak rate than the old R-12 type hoses. The flare fittings are fine, just make sure they are clean and no obvious scratches on the sealing surface. Don't overthink it, if it did not leak for R-12, it should also not leak for R-134a, although there is a very small difference in size where R-12 is a larger molecule. Go for it and be cool. One bit of advice, run as big and efficient of condenser as you can, R-134a needs more cooling to give best results. The old tube and fin style R-12 condensers are not enough capacity. Look at new cars and get the serpentine or parallel flow style like they have.
I have the exact a/c setup you've described in the truck in my avatar. I installed it 2 years ago, it works great, and I haven't had to recharge it yet. Of course o-ring connections would be preferred, but with the price difference and availability issues of r-12 I think its worth using r-134a IMO.
Thanks for the info guys, I'm gonna try it with my old Mark IV. I will be using a new Vintage Air condenser & R134 drier.
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