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  1. #1

    Default R12 A/C system conversion to 134??

    I have an '82 GT with air conditioning. I'm looking at purchasing the fittings to run 134 instead of R12. Has anyone done this yet?? Pros/Cons?
    Im in TX and I really need the cold air!

    Thanx in advance-

  2. #2

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    I recently bought an R-134 kit for a Fox. They say it will work better than just running R-134 in a system designed for R-12. Not cheap though, it's about $800. It does come with all the components new though, except the evaporator. They say you can just use your stock one. If you're system has sat dry for too long, it's probably a good idea to replace everything anyway. At least the receiver/dryer and probably a compressor. I got my kit from LMR.

    From what I understand though, if you want to use your existing system, you can at least improve things a bit if you swap to an SN95 condenser. It's designed for R-134.
    Brad

    '79 Mercury Zephyr ES 5.0L GT40 EFI, T-5
    '17 Ford Focus ST
    '14 Ford Fusion SE Manual

  3. #3

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    Yah I've seen those kits and they are nice but pricey. If I were going to keep it for years to come then I would consider it. I'm looking to get some air going long enough to make it through the summer.

  4. #4

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    I converted my system about 10 years or so ago. Reused my original compressor, condenser and evaporator coils. Just flushed them out really well with MEK to get rid of the old oil. Bought all new hoses/dryer, O-rings (green ones), and adapter fittings. New hoses say they are rated for R134. Filled compressor with PAG oil and assembled. Used vacuum pump to pull vacuum on system, then filled with refrigerant. Been working fine for me ever since. Never checked temps, but blows decently cold.
    Thomas

    1985 Mustang GT - Build Thread
    347 (Stock Block, Scat Crank & Rods, Probe Pistons, 11:1 CR, AFR 185's, PP Crosswind Intake, Custom-ground Comp Hyd Roller Cam, Scorpion 1.6 Roller Rockers, Holley 3310-4), T-5, 8.8 w/3.55's, MM SFC's, T/A, PHB, LCA's, Strut Tower Brace, K-Member Brace, Bilstein HD Struts/Shocks, MM/H&R Springs, SN95 5-Lug, Cobra Brakes, '04 Mach 1 Steering Rack

  5. #5

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    My 80 Cobra is still R-12, Its used very little Freon over the last 37 years, and is always ice cold. I do have many dozens of 1lb cans of R-12, so idont have a reason to convert at this time. for a few dollars in freon just keep factory?

  6. #6

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    R-12 definitely performs better... My Zeph still had a functioning R-12 system with the original drivetrain. Super cold. Wish I'd spent the time to try to make it work, but I got rid of the whole mess at once.
    Brad

    '79 Mercury Zephyr ES 5.0L GT40 EFI, T-5
    '17 Ford Focus ST
    '14 Ford Fusion SE Manual

  7. #7
    FEP Super Member erratic50's Avatar
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    Converted my 89LX 5.0 conv and my 86GT 5.0 to R134A 20 years ago.

    I simply used the switchover fittings and conversion oil. No messing around cleaning anything - I just made sure all the leaks were fixed up.

    My 89 only had 55K miles. The compressor was strong and the AC worked great afterwards. I installed the line keepers from NAPA while I was there. Did an old school "displacement" evac. Held open the high side and shot in R134a until it came out of the valve. Filled with gauges. It required about 1/2 can more R134 than the system said it held for R12 due to displacement approach. Air temps blew 45 while it was 110 outside.

    My 86 had 200K. The compressor was weak by pressure readings and the AC clutch was in bad shape, but functioned. It blew 47 when all done.

    I also used Artic chill on both cars.

    I notice almost no difference R134 vs R12. Maybe a degree or two if that.

    The 89 worked perfect until sold it in 2010 with 120K on it.

    The 86 worked well until 2001. Had to replace the compressor switch then. It worked well until I retired it from daily driver duty in 2005 plus a bit. Compressor and rubber lines are shot now, but that quick swap worked great for years and tons of miles.
    Last edited by erratic50; 07-11-2017 at 12:37 AM.

  8. #8
    FEP Senior Member gt4494's Avatar
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    Did the same thing "erratic50" did except didn't change O-rings. System worked fantastic for about 3 years before O-rings went out. Living in the south I will say it kept me plenty cool snd just oil and freon should get you through the summer if the system is ok to start with.
    "If you can't explain it simply, you don't understand it well enough."
    Albert Einstein

    1984 20th Anniversary GT350
    Almost "Stock"

  9. #9
    FEP Power Member vintageracer's Avatar
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    All I have ever done on a Foxbody to get the A/C going was replace ALL the O rings (it's either 9 or 11 O rings), with the system down install a new receiver/dryer, install a new orifice tube, evacuate and finally recharge the system with 134. I have never had to replace a compressor when getting a system back up and Kooling!

    The coldest 134 system I ever had was in my 88 Saleen SSP Coupe in which the evaporator core was also replaced which meant the A/C box got cleaned out of all the trash from over the years. That system blew as cold as any R12 system I have ever had.
    Mike
    Remember, "Drive Fast, Turn Heads, Break Hearts!"

    1995 Ford Powerstroke F350 "Centurion" STRETCHED Crew Cab Dually

    I like "Cut & Coach Built" vehicles!

    www.musclecardeals.com


  10. #10
    FEP Super Member sowaxeman's Avatar
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    Quote Originally Posted by Boss 429 View Post
    My 80 Cobra is still R-12, Its used very little Freon over the last 37 years, and is always ice cold. I do have many dozens of 1lb cans of R-12, so idont have a reason to convert at this time. for a few dollars in freon just keep factory?
    Many dozens...does that mean you are willing to sell any?
    Jason Smith
    MCA #65481

    '82 Capri RS Resto-Mod
    '88 #400 Saleen Coupe "Mean Machine" Legal Guardian
    '93 LX Yellow/Black Summer Feature - 2,800 Mile Original Survivor (Foxtoberfest 2019 Best Original 87-93)
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  11. #11

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    R12 is so cheap I just can't justify spending money to change over to something that nobody on the planet can argue doesn't work as good.
    Liberty once lost is lost forever.

    John Adams
    July 7, 1775

  12. #12
    FEP Super Member erratic50's Avatar
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    My AC broke on another one of my cars while on a trip. I was hundreds of miles from home. I went to the local Mcparts and got what I needed to fix it, did the displacement based "evac" and charged it. Back up and running in about an hour. THAT is the reason to convert. Availability of parts and supplies to service it. Just my $0.02. Would have had to strap my wife to the roof otherwise.

  13. #13

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    I'm going down the same path. Upgrading my A/C from R-12 to R-134a. My question relates to the A/C hoses. Is there a difference between a hose which is designed for R-12 and one for R-134a? I realize that I need to upgrade my O-rings, but I keep reading about "barrier" type hoses. Basically, will NOS hoses, designed for R-12 back in the 80's, work with R-134a?

  14. #14
    FEP Power Member vintageracer's Avatar
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    Yes the hose material is different. The 134 hoses are "barrier" type of hoses as the 134 molecule is much smaller than the R12 molecule. Because of this fact the 134 molecule can over time "leak" through the R12 hose. My experience is it takes awhile. A very long while!

    I would not spend the money for NOS R12 hoses UNLESS you are restoring a Top Flight MCA show car where you looking for appearance as much as function. Most every town has a hydraulic hose shop that can make new hoses with your fittings or fittings that will work on your system with the correct "Barrier" hose needed for 134.

    Just remember that 134 is on its way out ultimately to be replaced the newest refrigerant beginning to be installed in new cars HOWEVER it will take YEARS before this will be an issue on old cars.

    For old R12 type of A/C systems that you do not want to retro-fit to 134 I recommend you look at Red-Tek refrigerant (http://www.redtek.com/). Used it for years, works great and no hose issues other than the fact your hoses are already damn old and probably need replaced anyway.

    I stand by my statement above that the easiest, quickest and cheapest way to the A/C blowing cold and one that has worked for me every time on a Foxbody Mustang is to flush the system, replace all 11 O rings, replace the orifice tube, replace the receiver/dryer, add the correct oil, evacuate the system and charge with 134 or Red Tek. It's worked every time for me. I have NEVER had a bad compressor on a Foxbody. I have had compressors with a bad clutch or belt bearing but NEVER a bad compressor.

    If you have a factory A/C car and have to replace the heater core I always replace the A/C evaporator since I am already there as most everyone NEVER replaces the evaporator. I have found this alone most than makes up for the R12 to 134 cooling difference if you want to use 134. My experience is that Red-Tek refrigerant cools JUST AS GOOD as R12 so my suggestion overall is to not worry about your hoses, do what I suggested above and install Red-Tek and you will have "CHILLY WIND"!
    Mike
    Remember, "Drive Fast, Turn Heads, Break Hearts!"

    1995 Ford Powerstroke F350 "Centurion" STRETCHED Crew Cab Dually

    I like "Cut & Coach Built" vehicles!

    www.musclecardeals.com


  15. #15
    FEP Super Member erratic50's Avatar
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    I wore my compressor out on my 86. Took multiple clutch replacements before the compressor shelled out. It still turns over but it's noisy as hell and doesn't generate any pressure anymore.

    Took over 430K miles to shell it out. I've been beating on the old rust bucket without AC ever since.

    You can pretty much walk most junk yards and find a bolt in replacement compressor in minutes. Hell - that's probably cheaper than a Mcparts AC clutch kit.

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