I am installing an original A/C system in a 1972 Chevelle. It has a 307 V8 engine, the air compressor and all the brackets are original for a small block V8. The system was removed from another car and I have cleaned and reassembled everything.

To put R134a in the system do I need to replace the expansion valve, the POA valve or any other component? Can I use the same old original R12 parts?

Thanks!

Gil

http://www.chevelles.com/forum/Forum27/HTML/000237.html
That link should get you in the right direction. Also do a search on r-12 or 134a, you may find more info.

And welcome to the best site on the net!!

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70 Malibu 307 [URL=http://www.chevelles.com/showroom/17again.jpg]

http://www.aircondition.com/

I've finished rebuilding my A/C this past weekend, rebuilt it and tried the 134a and I couldn't get the head pressure down enough, in excess of 250 PSI with temps at the evap in the low 40's at best. Well, I gave up and switched back to the R12 and it's sooo much better, I get temps at the evap of high 20's/ low 30's.

If you decide to use the 134a you will need more air flow through the condenser to help keep the head press under control, plus 134a compatible txv, oil and 'o' rings. The POA valve should be replaced, 134a like a suction press. in the low to mid 20's, Old Air Products sells a POA conversion valve that changes the system to a clutch cycling arrangement, the good thing about that valve is the switch is adjustable if you ever decide to go back to R12.

Hope this helps,
Jimmy H.
'whatsupdoc'