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1970 El Camino- A6/ R12

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    1970 El Camino- A6/ R12

    Need some advice!
    I have a restored 1970 El Camino SS with 396 engine, with the original A6 compressor and R12.
    The compressor just blew the front oil seal (dang it). Now I need to correct it, while still keeping the original look of the engine bay (A6 compressor, POA valve, etc.)
    What the best resolve and procedure to for this?
    Stay with R12 or convert to 134?
    If I convert to 134 what need to be done? And can it still look orginal?
    Thanks In advance for the help!!!

    Depends on how long you are going to use it. There are a replacement seals for the A-6. There are two types. the 1st is the original type "face seal" which doesn't ride on the shaft and eventually wear a groove in the shaft, and a new more positive seal that does ride on the shaft but seals a little better.
    Hard to say on R12 vs R134a. Both are now on the list of being phased out. R134a will likely be easier to get for the next few years, 10 or 20 years down the road will likely be is hard to find as R12.
    The POA system will have to have the POA valve setting re-set to work well on 134a. Without resetting the evaporator temp will not get cool enough.
    I still run the A-6 and like it a lot. I bought all the factory tooling to overhaul, but parts are getting hard to find as it has been 40 years since GM was making them. There are a few places coping them.
    Other than re setting the POA and changing the oil to PAG 150, there isn't much you need to change for 134a. Make sure your condenser is in tip-top condition, with good heat transfer from the tube to the fins if using the stock condenser. It will preform better with a more modern type condenser if using R134a, but if you are trying to keep it close to 100% original looking, the original will do well enough if in prefect condition.
    Last edited by Cornbinder89; 04-10-2021, 02:43 PM.


      Wow, car of great interest! R-12? Look out there for it IMO as it doesn't leak as much and if you know just close RPMs, always the temp area is a sight glass takes guessing out.
      I'd really want to know leak is fixed?
      I'd waste some 134a as it's more apt to leak see how close you are to none with pressure not just holding a vacuum.
      A late friend was really into using 152a in R-12 systems claimed years of it working with just minimal loss if any noticed in BTUs exchanging heat. AYOR I still have new R-12 and use one that's OE with it in cold climates will leak out compressor shaft seal if kept stored warm (above 45F) will not leak much but some expected when new, really!

      Vintage or now antique cars/trucks came with an Lb of extra charge got you off warranty held so much worked fine an Lb over or under.
      In short, keep it R-12 it's out there losing value (a guess) as it's too easy to lose it with any mistakes now you may make or if you have to save it I think this set up can't isolate just compressor to save refrigerant if you just needed it out of the way to do some other work. Please say if you have "stem valves" no Schraders for this. 95% or more people I think would buy this car W/O A/C on purpose was a nasty costly option when new,

      MetroWest, Boston


        Coupla extra thoughts,
        1st the new type "lips seal" can be installed without dis-assembling the compressor, but CAN NOT be removed without dis-assembly like the older face seal can. Something to consider.
        2nd, After have mixed luck replacing seals in the truck. I now have the tooling and a special large vacuum gauge that I use when replacing seals on the A-6. After it has been installed and the correct oil charge placed in the compressor, I draw a vacuum with the vacuum pump on the outlet of the compressor and my special vacuum gauge on the inlet. Once I pull as much vacuum as the pump can, I disconnect the pump from the pressure checking fixture on the back of the compressor and see how it looks in a week. The large dial will show even a small pressure gain.
        Since I have three A-6's for two trucks that run them, keeping one compressor on the bench for a week is no problem.
        If I were going to use R12 I would likely use the lip seal, esp if the compressor is going to see low hr of use. In my heavy trucks it used to be that the compressors would see far more use in one season than a car would in 20 years or more. Some weeks running 24/6 days a week, only shut off when I got back home. with that kind of use, a face seal will allow the compressor shaft to last for an indefinite number of overhauls, A lip seal will wear the shaft sooner or later but will seal better in the mean time.


          Waterwalker: I hope this site is sending you notices that a reply was made - it doesn't for me just BTW. To add to what I wrote reason for testing with lousy 134a is smaller molecule would still sniff out not even run it. Take that right out don't run it on it.

          Other is Cornbinder89 is probably the web's most informed person on A-6 compressors I've even known! I redid one other type, failed so quit redoing any a long time ago.

          I did convert some untold # of cars to 134a simply costs and high use ordinary cars were NOT expected to last overall don't waste the bucks for a season or two.

          Your call I recall the late big block Chevys if this El Camino has matching #s in orig type shape it's a goldmine I would think. IDK if what refrigerant is in it would harm the value of this? If altered to another I would lube the retro fittings so it can look all OE if it's your desire but mark it that it's converted to another gas so no mistakes are made later understanding it.

          Funny looking back the small cab probably is such A/C overkill it's not funny wouldn't work very hard.

          Said, it's your car if mine I wouldn't alter it by looks if show quality now,

          MetroWest, Boston


            Thanks everyone for the input....
            Another question for all of you has anyone tried the Frosty Cool 12A product?


              Do NOT use those types of replacements. You have no idea what you are putting in. All commercial refrigerants have an "R" number assigned to them you'll notice they don't tell you what theirs is or what the make up of the stuff is.
              Any commercial shop would refuse to repair or would tell you that you have to tear it all out and replace with new. To work on stuff, they have to know what is inside to be able to recover and recycle the refrigerant by law. You can't mix refrigerants and if they encountered an "unknown " they would be on the hook for the whole 30-50lb recovery tank that can't be recycled or disposed of.
              More than likely it has either propane or some other refrigerant that is not legal for use in confined spaces mixed with 134a.
              There is a good reason 134a was used to retro-fit R 12. all the refrigerants out there, 134a was the best match for the job.
              The way to reduce head pressure is to shed the heat at the condenser. 134a has more trouble doing this than R 12. In the years since R12 was common, condenser design has improved a great deal.
              On my Semi truck retro-fits I increase the condenser size and capacity a fair bit, and my head pressure is very low even on 100 deg days.
              On a full- up restore, that you want to look 100% original. I would use the lip seal on the A-6 and use new hoses with crimp on fittings and R-12.
              If you don't care if the condenser is 100% original, then I use a modern "generic" type condenser, the biggest one you can fit in front of the radiator, and use R134a or R12 your choice on what you can get and afford.
              There is some talk of using the refrigerant in "dust off" cans (it has an "R" number that I can't remember right now) and some say it works well. IDK, if it was such a good solution why wasn't used to replace R12 when that was phased out?
              There are quite a few places selling "drop in replacements" for R 12 like the above link, but they sell primarily to the DIY market as no reliable shop would touch the stuff.


                PS, looked on their site and the MSDS for the product, it is what I thought UN 1075 Hazmat, In otherwords it is Likely a mix of R134a and Propane.
                Propane alone is a great refrigerant, and once was very common. There are rules as to when and where it can be used, and inside a car is not one of them.
                Imagine a wreck and a punctured line spraying flammable gases into the passenger compartment where they may be all kinds of ign sources.
                Propane is mixed with the 134a to carry the oil through the system, Its pressure at 32 deg F is almost exactly that of 134a.
                Much better to use straight 134a and the proper oil and condenser then that mix..
                UN 1075 is the international coding for LP or propane (LP can be propane or propane/butane mix).
                Last edited by Cornbinder89; 04-12-2021, 03:52 PM.


                  Sorry I'm late again! This site isn't sending notices of activity here - still.
                  So, NO to 12A as it's a whole different bird - also called Freeze12 isn't user friendly IDK if it lasts either. It's sold to Canada that outlaws everything.

                  152a is already a refrigerant by name BTW. I'll try to spell chemical name is a CFC. > " 1-1-difluorethane "< should plain say (HFC-152a) just read that off of a can of it!

                  It's in a "Duster" can with sprayer sold for about $4 bucks for 10oz of it. You use a side tap on it. IDK if sold to use another tap type yet.

                  This was TMK already approved as a refrigerant IDK if used in new things but think it is maybe not the US right now?? I think it is what propels spray paint now and other sprays, cleaners etc.

                  Another TMK is butane is purer than a propane (a by product of refining crude oil) also makes oils move better or at all.

                  Back: 152a is compatible with R-12 and mineral oil apparently has a patent # I think put through a Ward Atkinson (MACS Conventions) or an associate?

                  Info tough - lots of folks passed away when it was approved or close to the time this was a hot issue.

                  Best I can do, hate to say it's the best I can do if someone has died!
                  MetroWest, Boston