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78 Ford Country Squire.. Here we go!

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  • 78 Ford Country Squire.. Here we go!

    Of course I'm not here because the A/C works great with no issues!.
    78 Ford Country Squire wagon. Unsure how long the car sat (bought from grandson of original owner)
    Father decided to get the A/C going in it on R-134a. This uses a GM style (?) compressor.

    Anyway, replaced the compressor, drier, expansion valve, orings and fittings. vacuumed the system, charged it, and it worked for a week or two. Then it was empty.
    Checked for leaks, etc. Tried to recharge with a parts store valve. Wouldn't take it. Recharged, and now the pressures are, well, weird. 90sih low, 165ish high?
    Low is high, high is low. This was on an 85 degree day here in MA.

    Forgive my ignorance with terminology.
    The tiny silver line out of the evap that screws into the POA valve frosts up quickly. The bottom fitting up to the expansion valve is 'sorta cold'.
    The low pressure line is 'cooler' than the engine. The other line out (in?) the compressor is very hot.

    Between recharges my father did blow through the lines thinking something was blocked. All was clear but POA seemed to have resistance.

    Before we throw parts at this, any suggestions? My thinking is he should use a real vacuum pump to draw down the system and not a harbor freight 'blowby' type that he used. thinking there could be air in the system.





  • #2
    MA as in Massachusetts? OK, same I'm from/in Marlborough. This now so full of unknowns and need a host of questions answered like why did you replace parts and with what and what type of oil if known. Whatever you did worked and has been hot enough just tonight now is only 55F right here is no time to mess with A/C already.

    It worked need to know how much oil can out of old parts and how much you added. If none that's a problem that sets this back to a disaster.

    Should have a sight glass upstream from where you hooked up the red gauge not really used for 134a but you do get a clue using it in these.

    It either leaked out already or burned up new compressor very tolerant but nothing is with no proper oil. You can charge these with just touch and feel for temps without much trouble but need to know what's in it and that you started for a true and real vacuum. All bets off if you didn't.

    On these, seeing frost on pipes is usually low on charge will work a little for a while may have frozen evaporator then quit blowing cold or more likely leaked out.

    Just amuse me - what is that blob of looks like household expanding foam insulation?

    IDK if local could take a look and check if it's on the road. Was not into A/C when these were new if anything just add R-12 from small then 14oz cans till sight glass was right and just carry on.

    Super high % of these and everything else rusted the issue see the Cougar in another picture beside it. The Wagon BTW should be an A-6 might say "Frigidaire" on it IDK if a rebuilt what it might say?

    Unreal tolerant systems the cars rusted out before these quit running - frames no less! Owned sedan of this and a '79 Cougar last of that style never touched A/C in either worked fine or maybe boosted once still R-12 either can work but oil would matter totally or forget it you may have ruined it all over again with lack of correct oil or now way too low it could be failing already worse off than not touching it but don't know that yet. The lack of what was done to convert to 134a and what you replaced and how is now the issue to figure out so need to know more and a maybe can look at it for you if really in MA. Pot luck on that,
    Tom
    MetroWest, Boston

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    • #3
      My 1st guess is by blowing air thru the lines and using a venturi type vacuum pump, you may have moisture problems. I must admit I am a bit confused how the pilot line can frost if your low side is 90 psi?
      There is a 2nd low side fitting on the POA to help in diagnosis, it will show evaporator pressure, while the one closer to the compressor shows the suction pressure that the compressor is pulling.
      The A-6 likes Pag 150 when using 134a.
      If moisture is the problem than you have to get it out. either a real deep vacuum pump or a normal A/C vacuum pump and several "sweep charges" to pull the moisture out.
      You may have non condensable gas (air) in the system also, that will also give high pressure but you would tend to see a higher high side with that.

      The High side pressure reading doesn't indicate a lot of heat, so if the outlet of the compressor is real hot, there may be some restriction between the high side tap and the compressor, feel along the high side line from the compressor to the tap for any point where the line temp drops rapidly, you should loose heat gradually thru the condenser and the outlet should be marked cooler than the inlet.
      Are you charging by the weight the system calls for (with 134a it should be about 80% of the R 12 weight)?
      Last edited by Cornbinder89; 09-01-2018, 10:10 AM.

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      • #4
        Another possibility that comes to mind is the low side tap is not reading the pressure in the line, either the 134a adaptor on the line is defective, the valve core was left in the original 1/4" flare when the adaptor was installed, or the hose end is not depressing the valve core for some reason.

        Comment


        • #5
          Originally posted by Tom Greenleaf View Post
          MA as in Massachusetts? OK, same I'm from/in Marlborough. This now so full of unknowns and need a host of questions answered like why did you replace parts and with what and what type of oil if known. Whatever you did worked and has been hot enough just tonight now is only 55F right here is no time to mess with A/C already.

          It worked need to know how much oil can out of old parts and how much you added. If none that's a problem that sets this back to a disaster.
          Unfortunately, I don't know what he did. I signed onto this project late. I just wanted him to send it out to the A/C place in New Bedford that deals with old cars, to start with, but here we are :-/ In Freetown.

          Originally posted by Tom Greenleaf View Post
          Just amuse me - what is that blob of looks like household expanding foam insulation?
          Sigh, it is INDEED house insulation. I hate it, but it's what he did.


          Originally posted by Tom Greenleaf View Post
          Super high % of these and everything else rusted the issue see the Cougar in another picture beside it. The Wagon BTW should be an A-6 might say "Frigidaire" on it IDK if a rebuilt what it might say?
          The car is from TN, he bought it last year and brought it up here. Cougar is a friend of mine.. That car came up from VA. It is indeed an A6 style compressor. He changed compressors and driers because he 'figured it was bad' since the car was sitting....

          Last edited by psquare75; 09-01-2018, 02:03 PM.

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