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I keep blowing-out the compressor shaft seal

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    BTW if it were me, and I had any question if high pressure were partly responsible for the leaks, I would wire in a high pressure cutoff for the compressor, and the only reason I wouldn't leave it wired in would be for "originality judging at a car show.
    If the system uses a low pressure cut off switch at the receiver, a Binary (low and high pressure cut off) can be used that looks like the original, but does both.


      Well it's back in the shop and replacement compressor received from NPD. I started discussing some of the things learned here and was pleased to hear them confirm all the info written here (and then some). I'll keep you all updated of the findings and hopefully positive outcome.


        Good luck TomSS. A/C is a LOT to know is why it's not for every shop even. Bummer on failures as it can make it harder for the next try.

        Make sure they have a full history what conditions it was under and TEMPS when each failed. OMG, it's theirs to take it from there IMO make good on this job for you,
        MetroWest, Boston


          Did they get it solved? I hope!


          • Tom SS
            Tom SS commented
            Editing a comment
            Unfortunately NO! Toasted another compressor front seal. To bad I can't show you a video of it hissing away. Green liquid all over my engine compartment. The two different shops I used are rated high and I've used them before for other mechanical issues and was very pleased with their work. But since I bought the compressor and they installed it, you know where they are pointing to the problem.
            It worked for two days (nice and cool) then failed. So, if the is a blockage and pressure gets to high to blow the seal, it must be intermittent. I did pass everyone's comments and suggestions to the shop and they agreed and said they checked and did the tests.
            So, I know have over $3000 invested in my A/C and still doesn't work. I probably should have "shotgun" all the A/C components and replaced everything for what I invested. I'm now going to look for a specialty shop that deals with only auto A/C.

          TomSS: The possible value here is for others to know what fixed it thru troubles. Site is free to use by my insistence volunteer time from those with experience. Site itself isn't quite right I don't get notices of replies you may not either?
          MetroWest, Boston


            Ok, 1st order of business is to install a Binary switch at the receiver/drier. This will protect the system from excessive pressure by shutting down the compressor at aprox 375 PSI.
            It also will protect against running when the system is low. From what little I can find, that car Doesn't have VIR and just has a drier.
            Rockauto shows it to use a superheat switch type compressor with a Thermal limiter (fuse) to shut off the compressor if there is a problem.
            There are two main problems with the thermal limiter. One is the connector on the rear head of the compressor is just a small "pin", and if the wire falls off you have no protection what so ever. 2nd, it is slow acting and can't react to a sudden change.
            That assumes it is wired in to begin with. Many get removed/forgotten and the thermal limiter fuse gets jumped. When that is done, the compressor has NO PROTECTION what so ever.
            So, back to my first paragraph, either temporally (if"year 1 restoration is what you are after) or permanently wire a high/low pressure cut-off on the high side. It may require adding a fitting into the high side somewhere. The closer to the compressor the quicker it will react.
            None of this addresses the real problem. It does protect things however.
            It is possible that something 'Intermittently' plugs the system. Two things that can do that are moisture (Ice) which will melt away when the system shuts down only to reform when it is run again. Another is bead material from a bad drier.
            It could be as simple as a bad condenser not removing enough heat. It continues to build until it blows the compressor.
            With a working high/low pressure shut down, you can run it and see what kinds of pressures you are getting and still not blow the system.
            Without temp/ pressure readings I can't be of more help, but it is a start .Continuing to do over, what has already been done will not give different results. I don't think the compressor seal "failure" is the problem, just the symptom.
            Below is a picture of the rear compressor head and superheat switch.
            Not all A-6 compressors had a switch port. You need one with the port and switch to use the stock safety system.
            A switch port compressor can replace a non port compressor, but not the otherway around.
            Click image for larger version  Name:	CIMG3718.jpg Views:	0 Size:	1.58 MB ID:	4030
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            Last edited by Cornbinder89; 3 weeks ago.