Anybody swap an early an R12 to R134 system
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I'm pretty sure you are supposed to flush the r12 system before adding r134. If you bleed of the r12. Be careful it's under quite a bit of pressure. But bleed it off and use the r12 to r134 adapters and charge the system
Update.
There is also a different pressure switch for the evaporator. Its specific to r134a conversion. Without this switch the compressor reads incorrect pressure and cycles too many times, then turns itself off until you unhook battery and clear the memory. Similar to running without freon or too low of pressure.
There is also a different pressure switch for the evaporator. Its specific to r134a conversion. Without this switch the compressor reads incorrect pressure and cycles too many times, then turns itself off until you unhook battery and clear the memory. Similar to running without freon or too low of pressure.
jkeaton
It’s been real
Make sure you properly recover the R-12. Don't wan to piss off the tree huggers...
mariodave
Newbie
I converted a 1989 to R134 I went to the junkyard and pulled all the parts off of 94 and 95 trucks. You need compressor, evaporator, condenser, drier and lines. Nothing interchanges, you need it all and some creative rewiring. Also , it is a lot of work to remove the HVAC unit.
DerekTheGreat
Forum Regular
You don't need a compressor, evaporator, condenser, drier or lines. A new drier/accumulator is a good idea though. I've had at least four cars converted from R12 to 134a with no issues. One of which being my '89 Firebird which is pretty much the same set up as these trucks. It's been going fine for the past 6 or 7 years on the original parts. Last year I had my '89 K1500 converted. Both of these blow ice cold air even when it's 85+ outside. Both still use all the factory installed stuff, Fireturd may have gotten a new drier. My K1500 does have a new compressor though, only because the other one sounded like a dying cat and had probably been dead for at least 15 years. Hardly anyone fixes "non essentials" in Michigan it seems.
Supercharged111
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That's because everyone in MI is broke. 
Seems that functioning trailer lights /brakes are also considered optional back home. Isn't the 95 condenser bigger for the 134?
Seems that functioning trailer lights /brakes are also considered optional back home. Isn't the 95 condenser bigger for the 134?
You need to flush the system to get all of the oil out. 134a uses a different ester oil which isn't compatible with the mineral oil used in R12. I replaced the receiver/drier and orifice tube when I did mine about 8 years ago. Last year my compressor clutch went out, since it was leaking a little I replaced the whole compressor. The evaporator and condenser are still OE. I get plenty cold air even in 110* ambient temps.
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