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R12 to R134 conversion...

Discussion in '1973-1991 K5 | Suburban | Truck' started by Mike87, May 1, 2000.

  1. Mike87

    Mike87 Registered Member

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    What do I need to change when going from R12 to R134 on a 1975 K5 Blazer with factory air? I know that I need to change some seals and hoses, but what about the compressor, condenser, evaporator, expansion valve, etc..

    I am debating over this to change to 134 or fix one hose and recharge my R12 system.

    Thanks,
    Mike (#87)
     
  2. Michael

    Michael 1/2 ton status

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    Mike, you might try a search for 134....this was discussed allot awhile back. I would stay with the R12 or consider a replacement R12 like http://autofrost.com. but that's just my opinion. All the old oil should be flushed from your system and seals replaced to work very well. Good luck.....I'm gonna have to do something on my '74 also.....it's gettin' hot in Texas!

    Michael [​IMG] http://jmartin.net/parker/goose.htm
     
  3. Casey 86K5

    Casey 86K5 1/2 ton status

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    I did the 134a conversion on my 86 last summer. If you want to do it right, there is a lot involved. First off, you need to replace all of the o-rings in the system with ones designed for use w/134a (they are green in color). You should get all of the old R12 oil out of the system that you can, a little leftover oil will not hurt. You will have to get 134a low and high side service fittings, and a 134a expansion valve (R12 expansion valve will work, but AC works better w/special 134a valve, you should also change the pressure cycling switch on your accumulator. The biggest problem with 134a conversions is the condenser- it cannot remove enough heat from the system especially when you are sitting in traffic, so I would recommend getting a condeneser for use w/134a or at least get a helper fan. I would guess that your system holds about 3 1/4 lbs of refrigerant, you want to charge it with a little bit less 134a because of the higher pressures.
     
  4. Eagle86K5

    Eagle86K5 1/2 ton status

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    Casey is telling you right, I had to replace the condenser coil in mine, it made no sense in the world to go back to R12 when 1) they don't make it anymore, 2) it is expensive as heck. I bought a retro fit kit, you see it at J.C.Whitney for 45.00 and an o-ring kit. I replaced all the o-rings, had it flushed ,replaced the inline filter and had vacuum pulled down to 30 and it held for a half hour, dumped in a can of 134 oil, then three cans of 134. System seems to work just as good as before, now when it is 100 outside and the truck has set in the sun all day...it does take a few minutes to cool down, but for me it works just as well as the old outlawed R12. And it is not that I cannot afford it, but I would much rather pay 2.50 for a can of 134 then 38.00 for R12.And there is a federal mandate...no more R12 is to be made, it is a felony to dispurse R12 into the environment, and it is supposed to be done by a certified mechanic. Once the available supply is used up everyone will have to go to 134, and if you know anything about supply and demand, better to do it now then when you absolutly have to cause the price just went up.

    <font color=green>[​IMG]Eagle86K5[​IMG]
     
  5. CrazeeBush

    CrazeeBush 1/2 ton status

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    Had to rework the whole AC system on my truck this past summer. I was considering the 134 retrofit, but decided against it. I'm so glad I didn't. My truck nearly blows frost. =) hehe My friend did do the 134 converison on his, and there is a big difference. There is an organic R12 substitute that cools VERY well. I had to use 1 can since I didn't have quite enough R12 to finish filling it up.(Friend's dad bought massive amounts just before it was outlawed...) I'll post the name of it when I remember it.
     
  6. turbo

    turbo 1/2 ton status

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    Best bet drive to mexico and get system charged.
    They make it there and it is the good stuff.
    Legal to get system charged there and drive home just don't bring back any outside you AC system.
    Screw these feds mucking with old cars.
    Outlaw new systems fine but let the old systems run in peace.
    Remember no more leaded gas feds screwing the old hot rodders but they still let the piston engine planes run leaded typical fed double standard.
    Echo terrorist do gooders need a life of their own.
     
  7. Russell Keys

    Russell Keys 1/2 ton status

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    I don't know about anywhere but TEXAS but they do make something called Freeze 12 that can be used instead of R12. This stuff cools just as good as R12 and costs the same as R134a. Charged my system with it and haven't had a problem yet. Seems the way to go instead of replacing all the components that are recommended when converting to R134. Personally I've never thought that R134a cools near as good as R12, but some people have had luck with it.
     
  8. Blazer79

    Blazer79 1/2 ton status

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    If you want some good info, go to http://www.aircondition.com They even have disussion forums similar to this just on A/C systems.

    <font color=black>//////
    What the heck!...Drive it like gas is $0.50/gal!!!
    </font color=black>[​IMG]
     

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