Looking for some AC advice/ info

Discussion in 'The Big Chill' started by Bogus919, Mar 9, 2021.

  1. Bogus919

    Bogus919 Silver Level contributor

    Hello all, thanks for giving me your time. So some background: I’ve had my GS for about ten years and it has never had a belt on the AC compressor. I know from talking to the original owner that the AC stopped working at some point but he’s not the mechanic type so the information he gave was pretty limited.

    So I have been troubleshooting the system to see if I can fix it. I have narrowed it down to one major issue, the compressor pulley will not turn by hand (hence the reason it has no belt, Likely). The clutch portion in front of the pulley will turn but the inner portion where the belt groove is will not turn. The thermal limiter is bad so I have it removed and when I jump the green wire (with the ac controls on) I hear a solenoid-like click... when this happens, the outer clutch portion will no longer move but also the belt groove portion still won’t. I am pretty certain that all of the internal electric components are operating as normal.

    Could this be a pressure switch that not allowing the compressor pulley to turn? What are some issues you have seen that would cause this? I was pretty certain there was no Freon in the system but briefly depressing the shraeder valve at the rear of the compressor gave a hiss.

    Also, I tested the superheat switch at the rear of the compressor and it is not grounded, which tells me it is open and good. I did this by checking for source voltage between the superheat terminal (part of thermal limit housing) and the middle green wire terminal that supplies source voltage.

    This is the original R12 system that came with the car in 72.

    Last edited: Mar 9, 2021
  2. Bogus919

    Bogus919 Silver Level contributor

    The more research I do the more I feel it is locked up. I have a second compressor from the 455 that I will test tomorrow to see if it is any different.
  3. Dr. Roger

    Dr. Roger Stock enthusiast

    Locked up compressor/clutch is the major reason most people take off the belt. Otherwise it smokes and screams like a banshee.
    Bogus919 likes this.
  4. Smartin

    Smartin antiqueautomotiveservice.com Staff Member

    Pulley should spin freely when AC is not engaged. When clutch is engaged as AC is turned on, it magnetized against the pulley and causes it to spin the compressor internally to start pumping.

    Soooo...you need a new compressor :D
    Bogus919 and Max Damage like this.
  5. Bogus919

    Bogus919 Silver Level contributor

    Thanks guys, I wanted to make sure I wasn't leaving something out when I was considering what would keep it from moving. I tested every part of the system up to that point and it was the only thing that wasn't working the way I felt like it should.

    Thanks again
  6. Wildcat GS

    Wildcat GS Wildcat GS

    This is VERY typical issue, I`ve repaired same many times...the pulley bearing is shot and locked up. You can replace the bearing only and test the compressor. My bet is, if your car doesnt have a ton of miles, your compressor is OK
    Tom Mooney
    Bogus919 likes this.
  7. Bogus919

    Bogus919 Silver Level contributor

    Tom, I actually just pulled the compressor off tonight and noticed I could turn the clutch but the pulley is slightly cockeyed and won’t budge. When I turn the clutch I hear and feel compression at the back two inlets/outlets.... so the internals are moving and it’s likely salvageable. I’ll look more into this bearing ... my backup/replacement compressor has a slight drag sound to it when I turn the pulley so it may have a similar thing going on, thanks for the feedback.
  8. Smartin

    Smartin antiqueautomotiveservice.com Staff Member

    You’ll need an AC compressor pulley puller to get it off. Once the pulley is out, you can knock the bearing out of the pulley and replace it. When you reinstall the clutch, make sure you have the right clearance between the clutch face and pulley.
    Bogus919 likes this.
  9. Bogus919

    Bogus919 Silver Level contributor

    Thanks guys. I have an extra compressor that I used. I will fix the bearing on the old one and hang onto it. Thanks a ton.

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