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Original A/C on 62 Hardtop

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  • Original A/C on 62 Hardtop

    Hello,

    Im wondering how to tell what A/C gas my system is using? There are no tags specifying and I'm guessing the system has not been converted. I would like to take it in to get the system checked out and topped off but maybe its better to fully evacuate and refill? It has never been serviced or used more than few times in the last 7 years. The site glass is dirty from the inside i think and hard to tell whats going on within the system. It does blow cold but could be colder. If i recall, before i replaced the thermostatic switch several years ago, the unit and hoses were frosting up. If i take it in to have the system pressure checked and refilled, how long should the process take? I have read that some systems seems take many hours to ensure full evacuation of the old gas. Should the system be flushed out fully after evacuation, before refill? Will oil be added? I just want to be able to ask the right questions before allowing the shop to do the work. Thanks to all who reply.
    Attached Files
    sigpic1999.jpg

  • #2
    Your system originally used R-12. It appears by the adapters that it may have been converted to R-134. Using R-134 with the factory hoses is not the best idea. R-134 has higher pressures than R-12 which the hoses weren't designed for. To totally evacuate the system and refill shouldn't take more than an 1/2 hour using modern equipment. Your system takes 9 ounces of oil. A pro shop will know what to do.

    John
    John Pizzi - Squarebirds Administrator

    Thunderbird Registry #36223
    jopizz@squarebirds.org 856-779-9695

    https://www.squarebirds.org/picture_gallery/TechnicalResourceLibrary/trl.htm

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    • #3
      Thank you for your response John. If the hoses i have currently installed are not rated for the 134, can i simply replace some hoses or must something else also be done to the system components as well? If the system shows no sign of a leak, "YET", is it worth continuing to use the 134 as is? I guess i would like to make the A/C last as long as possible. I read that r12 system pressure is up to 225psi and r134a is up to 250psi. I am not sure how accurate the source i read is. If my system is converted, i wonder what was changed, if anything, during the conversion.
      sigpic1999.jpg

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      • #4
        It appears that only the fittings were changed so the R-134 could be used. The other parts all look original. Everything else should be ok if they are not leaking. I would just replace the hoses.

        John
        John Pizzi - Squarebirds Administrator

        Thunderbird Registry #36223
        jopizz@squarebirds.org 856-779-9695

        https://www.squarebirds.org/picture_gallery/TechnicalResourceLibrary/trl.htm

        Comment


        • #5
          Perfect. Thank you. Its good to go into the shop with a bit of knowledge.
          sigpic1999.jpg

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          • #6
            I'll be interested in the outcome, as I will need some AC work done soon....keep us posted on your progress. Thanks and good luck!

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            • #7
              I noticed a little hiccup this evening as i tested the A/C and how cold it was blowing. I drove for about 30 minutes with the A/C on and whenever i accelerated the A/C and blower stopped or became very low until i took my foot off the accelerator. Once it was blowing cold again it would stay on until i needed to accelerate up a hill or from a stop light and again it would temporarily stop blowing. I remember reading something about this years ago but my memory is not what it use to be. I'm guessing a thermostatic switch or fast idle switch but can't seem to find an explanation if it is in fact an adjustment needed in one of those switches. The shop manual covers adjustments in this area but unless i missed it, it doesn't say why. Is this temporary blower shut off just a gremlin for this A/C or is there something i can adjust? In modern vehicles, i read-out a check valve from the vacuum line but could that be this issue as well? I open the hood once i pulled over after 30 minutes of driving and one A/C line was cool and wet and the other A/C line was warm. I will keep on reading to see if this has been addressed in the forum. Thank you to all who reply.
              sigpic1999.jpg

              Comment


              • #8
                A PO has the system converted to 134a based on the fittings in Photo 1. The hoses are all new since they are aluminum fittings vs. the copper evaporator (see the 3rd photo). You can google the SAE numbers on the hoses to confirm. The cycling is the pressure switch, indicating that you are low on freon. Since it blows cold and isn't making grinding noises all you need is to add a little more. A local shop with a gage set can do this for very little money.

                "If it ain't broke, don't fix it."

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                • #9
                  Good catch on the hoses. They do appear to be compatible with R-134.

                  John
                  John Pizzi - Squarebirds Administrator

                  Thunderbird Registry #36223
                  jopizz@squarebirds.org 856-779-9695

                  https://www.squarebirds.org/picture_gallery/TechnicalResourceLibrary/trl.htm

                  Comment


                  • #10
                    Thank you gentlemen. Spending as little as possible is a good plan but I was thinking about the site glass. The site glass is extremely dirty and I cannot see if there is any liquid inside let alone bubbles. I thought that a flush might be in order, not only for the integrity and efficiency of the system but also to be able to monitor its health. It almost looks like the site glass is on a separate fitting?? Maybe look into replacing that fitting only. If there is a way without loosing charge from the system.
                    Last edited by flyinthermals; June 28th, 2020, 02:26 PM.
                    sigpic1999.jpg

                    Comment


                    • #11
                      I was reading the posts again and i did notice a growling, vibration (like driving over rough pavement on a skateboard) sound felt in the gas pedal when the A/C is on. Not all the time but under acceleration mostly. Its hard to describe but defiantly not present when the A/C is off. its audible as well.
                      sigpic1999.jpg

                      Comment


                      • #12
                        It it only happens with the ac on it could be the compressor. Sometimes a worn bearing will cause a vibration.

                        John
                        John Pizzi - Squarebirds Administrator

                        Thunderbird Registry #36223
                        jopizz@squarebirds.org 856-779-9695

                        https://www.squarebirds.org/picture_gallery/TechnicalResourceLibrary/trl.htm

                        Comment


                        • #13
                          Thanks John. I will keep that it mind.
                          sigpic1999.jpg

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                          • #14
                            I started to troubleshoot the vacuum system and some more questions came up.

                            1. When i turn off the ignition how long should the A/C door stay open? Is it suppose to close right away or does residual vacuum in the canister keep the vacuum system charged and therefore the door open for a while before the vacuum system is drained? My A/C door closes immediately after turning the engine off.

                            2. I started troubleshooting at my check valve from the manifold and discovered that blowing towards the canister through the valve air flowed freely. Blowing through the opposite direction i noticed a small amount of air went through. Should this check valve prevent all air from going back towards the manifold or is a little acceptable? Is this small leakage enough to be considered a leak and enough to cause the symptoms the A/C is experiencing when the blower fan and A/C shuts off when i accelerate?

                            3. If this is indeed a check valve failure, where can i find one? I have been looking around and all i see is plastic valves. Can this be rebuilt?
                            Attached Files
                            Last edited by flyinthermals; June 30th, 2020, 03:07 AM.
                            sigpic1999.jpg

                            Comment


                            • #15
                              The check valve should be closed in one direction. You can try spraying some carburetor cleaner into it to see if it fixes it. Sometimes dirt or carbon can get in and cause it to not seal. If not a plastic valve will work just fine. That could be causing the issues you are having. I would also check the canister. They are notorious for leaking. The pipes where the vacuum lines go can become loose and leak.

                              John
                              John Pizzi - Squarebirds Administrator

                              Thunderbird Registry #36223
                              jopizz@squarebirds.org 856-779-9695

                              https://www.squarebirds.org/picture_gallery/TechnicalResourceLibrary/trl.htm

                              Comment

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