R12 to R134

Getting ready to charge the A/C in my 71 Mopar with R134. The original R12 is long gone. I have a new R12 dryer that I am planning on using after I throw the old one away. Can I indeed use my new dryer for 134 or does it take a different one now that I'm changing from R12 to R134?
Thanks

I charged an R12 system to R134 on a 72 Charger. Replaced the dryer on an original type and had a tech evacuate the system and charge it with R134 oil and freon. It worked great and ran for two summers and then the compressor locked up on the way home from the Nats. I understand the cause of the failure was either not all the old oil was evacuated or the higher system pressure of the 134 or both. The answer to your question is in my experience it will work but other problems will probably shorten the life of the compressor. FWIW I changed the entire system over to a Sanden compressor with a new dryer and hardware. Still running the old condenser.

Thanks for the reply. I may try it with the NOS dryer and see how things go. I may also replace the compressor for peace of mind. The hose are the original ones so I may have problems there too.
Thanks again for your input.
attaboy

Don't do it.

Back in 1997 iI bought a 95 GrandAm that was hit in the front, needed a new radiator and AC condenser, changed them out ,put in a few cans of 134 , didn't even pump the system down. Air was cold and never had a problem,. Put over 100,000 miles on that car and the air still was cold.

And a 95 Pontiac has ZERO to do with a 71 Mopar's AC system, care to guess when what year R134 was mandated?

1995

I was gonna do it at one time & I checked into it somewhat & they said: convert to the "barrier"? hoses, replace the reciever/drier, replace the valve that sets just forward of the firewall there on one of the two lines that come out from it, do something (change?) the oil in the compressor and maybe some more things. Heat dont bother me so I let it slide & I've been in some R12 cars & its like being locked in a cooler

I've done quite a few conversions on early 90's Toyota vehicles with zero issues. I have done a conversion on a 68 Chrysler 300 and retained the original hoses,drier, and compressor. The owner has been using it for 3 years with no issues at all.
The automotive industry was putting out some ridiculous claims that your system would be ruined and you have to change all your rubber components before you make the conversion. It's all just a bunch of propaganda to make you buy more parts $$$.
I have had good results with all my conversions

Gus

I converted my '69 Cuda Fastback to 134a. I prepped the system by:
- removing and cleaning the sump on the compressor to remove all the old oil
- changed all O rings to 134a compatible ones
- kept original hoses
- flushed the condenser and evaporator and all lines with A/C flushing fluid (removed the condenser and laid flat to get better flush)
- installed new 134a drier
- installed new expansion valve for 134a
- vacuum dried, added oil and charged with 134a to about 75% of R12 charge.
Works great!!!

Same here as I have changed a bunch of cars from R-12 to the R-134 and all have worked good with no problems. As Gus said when they first came about they were telling us we had to change alot of parts including the comp on some cars. Then a few years later they changed what they said. You should evacuate the system real good and use the right comp oil for the R-134. I have done many and have not changed the comp or drier on some. But I tell the cust to change the drier as thats the way I was taught on AC systems but like I say they have worked fine for me even on the ones where the cust would not let me change the drier or accumulator. Ron