Topic: conversion from R12 to R134
in Forum: C3 Cooling and Heating Systems
Lifetime MemberSimplest way for me was to get an R-12 recharge hose with a 45 degree fitting in the end and cut both hoses and splice the 45 deg. end onto the new R-134 hose, fits like an original R-12 setup. Back up one page in the thread for more discussion on this little wart in the A/C mount crash.
Dave
BTW.... Mine is still blowing cold air out of the foot vents only.I have not dug into it yet. Any quick hints from an ASE Master at a simple way for a guy our age to easily (?) get to the vacuum diaphragms to check out which to open and close to get it blowing cold in my face? I have never even found or seen the things.
I did drive the thing to Florida and back last month, nice trip down, 20 MPG avg. @ 80 - 85 MPH, beautiful weather, but back in the non-stop rain from Montgomery to Nashville....... MISERABLE!!!!!! I parked it when I got back and have not even touched it since, still nasty dirty.
Dave
No easy way. The vacuum controls operate the vent doors. The system either is not switching at the control head in the console, or you have a vacuum leak. This is a small enough leak that the engine is not affected. Where is the leak? Darn good question. It can be a loss at the engine connection all the way into somewhere in the dash.
If you don't have a hand vacuum pump, use a long piece of vac line. Connect it to the running engine, and use that for a source for testing. It can even be connected to another car, you just need a source. In you car I would suspect the control head vacuum switch. But if some one has worked on the dash, all bets are off. They could have a leak or a pinched line blocking vacuum anywhere.
adaptors do require removing the old valve core first.[/QUOTE]
ken- thanks for the heads up- so what happens if that old valve
core will not come out? it unscrews easily just like your typical
inner tube valve, but it will not come out! The lower part of the
valve core seems to be attached somehow inside. this damn
little 10¢ valve is the only thing in my way now! AAAAARGH!
has this ever happened to you? what a p.i.t.a.!
oh, and thanks for input too, dave- might end up doing that if the
adapter does not work- that rig you made up sounds like a
good idea.
Okay
New problem with the converted system. I replaced the accumulator , had the system vacuumed and charged with 134a. Now, I won't complain about the coolness because I knew that going in it wasn't going to cool as much.
The compressor (R4) is making ALOT of noise. I've read that the compressor oil is carried with the 134 coolant. So, is it possible that the charge didn't contain enough oil to lube the pistons in the compressor or is this just a case of a 27 year old part going bad. I mean I'm willing to swap out to a new/rebuilt R4 but am I just going to have this problem again with the new one?
Jim
Lifetime Member #73
The Money Pit.... and my niece 
(click to see a slightly larger version)
How accessible are the vent door actuators? I'd like to try running vacuum directly to them first then work my way back to the control head, replacing the tubing with new nylon or urethane flex tube. No sweat on the vacuum source, I have a super vacuum pump that will get down to 29.95++" hg.
Dave
ive got icicles growin on me beard!
turns out that sometimes the the old shrader valve core will get
stuck
in there, and needs a little coaxing (ok- a lot of heavy yanking)
to
get that bugger out. once i got it out, i put on the brand new 90
degree fitting i got from napa, and the rest was a snap! seems
to blow
cold and works well.
thanks for the help guys!- one more reason why i went gold!!!!!
if anyone else has the problems i had- heres a scan of the part i
got from napa and a little rough sketch of it
What are thoughts on using a hydrocarbon refrigerant? ie. Like RedTek as mentioned in dcfblujeans post above. I read their product brochure which indicated it is designed as a direct replacement for R12 and R134a. Seems it takes less head pressure so it's compatable with existing oil, seals and components. I called them and they indicated with a current sealed working system, their product would directly replace my R12. The Retro and Charging Kit they sell is $54 bucks. Gonna give it a shot.
-Eric
Ah, all this talk about a/c conversions! Makes me wonder how much grief I'll run into trying to get the a/c from a ' 94 lt-1 to work with the ' 76 plumbing . I have replaced the engine in my ' 76 with a ' 94 lt-1 , and everything has had to have been custom made, more or less. I'm thinking some custom work might have to be done to the a/c as well ? Any thoughts 
