AC Conversion from R12 to R134a. 1970 DeVille
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  • 2 Post By Bro-Ham
RWD 19xx-1984 DeVille and Fleetwood,
1985-1996 Fleetwood and Brougham Forum Discussion, AC Conversion from R12 to R134a. 1970 DeVille in Past Cadillac Vehicle Discussion; I have a 1970 DeVille. I just rebuilt the motor and I'm about to put it back in. I'm looking ...
  1. #1
    jc4now is offline Cadillac Owners Member
    Automobile(s): 1970 Deville Convertible
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    AC Conversion from R12 to R134a. 1970 DeVille

    I have a 1970 DeVille. I just rebuilt the motor and I'm about to put it back in. I'm looking at the AC system. Has anyone converted their AC from R12 to R134a? I'm told there are a TON of "leak points" in these older systems and going to R134a could become a nightmare process. R12 is SO expensive and and becoming quite scarce. I cannot afford (or want) to keep dumping it in just to have it last a few months. Someone here has HAD to have done this. IF I start the conversion, what headaches am I looking at? What are the Pit Falls? What wisdom can you share. What should I do and definitely not do? Thanks.

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    Bro-Ham's Avatar
    Bro-Ham is offline Cadillac Owners Connoisseur
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    Smile

    Do a search on the forum and you will find plenty of answers to this question. I converted an older Cadillac to 134 about 10 years ago, it didn't cool the car very well, had it almost immediately switched back to R12 and all was good. I have R12 in my current 79 deVille and won't convert to 134 for all the cocktails in Florida!
    CADforce69 and CADforce69 like this.

  4. #3
    Robin Banx's Avatar
    Robin Banx is offline Cadillac Owners Fanatic
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    Re: AC Conversion from R12 to R134a. 1970 DeVille

    ^^ What Dave said. He was lucky in that he dumped the R134 charge early on and went back to R12. The R134 attacks the lining inside the older high pressure rubber hoses, dissolves it and deposits it in the compressor thus rendering the compressor useless over time. I have two nearly new compressors which had been installed in conjunction with the R134 "upgrade" (in cars which later became parts cars) and are now seized tight with the residue from the disintegrating hoses. We have four R12 cars in the family and I will not allow R134 anywhere near them. Unfortunately I have to drive down to Washington state to have them charged but it is a small inconvenience to preserve systems that are in good working order. My '83 Bro will freeze fish in the front seat with the A/C set on high.

    Cheers........R.

  5. #4
    sven914 is offline Cadillac Owners Connoisseur
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    Re: AC Conversion from R12 to R134a. 1970 DeVille

    An alternative to R-12, is a product called Freeze 12, which is fully compatible R-12 components and provides comparable cooling. Unfortunately, Freeze 12 can only be purchased by someone with a refrigerant licence (unlike 134a, which anyone can buy), so you will need an A/C repair facility to retro fit your system.

  6. #5
    SafariOne is offline Cadillac Owners Fanatic
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    Re: AC Conversion from R12 to R134a. 1970 DeVille

    I put R134a in my 81 Fleet. about four years ago and it still is holding fine. The point was made about it not being as cold which I think is true. I have rebuilt the whole system and it was very clean inside. There was a bit of debris in the orfice tube but not sure how much it take to affect the cooling. I plan to go back to the same when I recharge it in the spring. I like the idea of topping it off myself if the pressure drops below a certain point.

    ----------

    Something I forgot to mention is that if you are doing it yourself....DON"T forget the oil. There is approx. 6-8 ounces of oil to go in the system. Some new compressors have it in already and some do not. And always put on a new accumulator, and orfice tube.

  7. #6
    carnut is offline Cadillac Owners Master
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    Re: AC Conversion from R12 to R134a. 1970 DeVille

    My 84 is filled with a $3 bottle of propane! been there for over a year. Freeze12 is virtually propane. read about it on www.benzworld.org If I develop a leak, I'll smell it!

  8. #7
    bornonthebayou's Avatar
    bornonthebayou is offline Cadillac Owners Member
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    Re: AC Conversion from R12 to R134a. 1970 DeVille

    I had mine converted over to R134a last summer after a couple months of no air conditioning. It is definitely not as cool as the old R12 was, but so far it is working fine. Now some of y'all have me worried about the long term consequences, but after looking into the R12 thing it just seemed like too much of a hassle.

  9. #8
    sven914 is offline Cadillac Owners Connoisseur
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    Re: AC Conversion from R12 to R134a. 1970 DeVille

    Quote Originally Posted by carnut View Post
    My 84 is filled with a $3 bottle of propane! been there for over a year. Freeze12 is virtually propane. read about it on www.benzworld.org If I develop a leak, I'll smell it!
    I've searched that site and couldn't find anything about Freeze 12 and Propane. The whole idea that a group of over privileged Mercedes owners, would be better informed than Cadillac owners, is entirely ludicrous (I should know; I also own a Mercedes).

    But more to your point; Freeze 12 is not propane is any way shape or form. Here are the Material Safety Data Sheets, listing the ingredients and hazards:

    Freeze 12:

    http://www.technicalchemical.com/msds/6030.pdf

    Propane:

    http://www.airgas.com/documents/pdf/001045.pdf


    Freeze 12 is mixture of two different refrigerants, which have been used (safely) in automotive and residential application for years. The MSDS also notes that Freeze 12 has a flammability rating of 2, which means it is only combustible if heated to 200º, and ignited with a spark; propane on the other hand, is combustible at any temperature, and a small leak can be ignited by an static electricity, or an open wire, or the distributor cap.

  10. #9
    Fleetwood472 is offline Cadillac Owners Fanatic
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    Re: AC Conversion from R12 to R134a. 1970 DeVille

    If you swap over to R134 make sure you change the accumulator. Also you can try using a GM V5 or V7 variable compressor. The reason people always say that R134 doesn't seem to blow as cold is because they have the pressures wrong. R134 actually operates at a higher pressure. If you pick up a V7 or a V5 with a R134 regulator it will regulate the pressrue correctly and it will run cooler. It might not be as cold as R12 but it will still be very cold. Here's a link to a guy with a 72 nova that he converted to R134 and modified it for a v5 compressor. As you can see in the video his car blows plenty cold:

    http://www.youtube.com/watch?v=P5hkkgqcE3Y

    The barrier hoses should be replaced due to age anyways so once you modify a bracket to hold this compressor you can shorten or lengthen the hose and have new hoses crimped on at an AC shop. Good luck. R134 to me would be a good option to go with. What's nice with the V5/7 compressors is they are variable so your system wont constantly cycle on and off. It will lower to the percentage of pressure needed to maintain the correct pressure.

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