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Air conditioner clutch shim removal

Discussion in 'Article Submissions' started by jsheahawk, Jul 24, 2017.

  1. jsheahawk

    jsheahawk Well-Known Member

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    If you have problems with your A/C clutch disengaging when the weather gets hot, removing the shim behind the clutch plate might solve your issue. This is an easy one, and the toughest part for me was getting the magnet wires back probed. All told, this fix took me less time than it took the wife to get back from the grocery store.

    This is all you'll need to do this job:
    14mm socket and accompanying ratchet
    Two wires with alligator clips on both ends
    A couple T-pins
    Pick set
    Flat blade screwdriver

    IMG_20170723_134131.jpg image_16048.jpg 800-041.JPG

    The compressor is straight down from this arrow. It's on the bottom below the alternator. If you don't know where it is, you probably shouldn't be attempting this. :biggrin:
    31420540006_large.jpg
    2005-gmc-envoy-42-engine-BDgNBSz.jpg

    Throw the 14mm socket on the center nut of the compressor clutch, and you'll find out pretty quickly that it just spins because the clutch isn't engaged. You could buy a special tool for this, but the clutch will do all the work for us if it were only engaged. Luckily electromagnets aren't exactly complex things; they just need power!
    DSC04407 (1).JPG
    Backprobe those two wires that come out of the right side of the compressor. Red is positive, black is negative. Put the socket on the nut now because it'll be harder to get on there with the magnet engaged. Connect the wires straight to the battery, and you'll hear a satisfying click of the clutch engaging. Jumping the relay is probably a more elegant solution. It's #44 under the hood. Thanks, Moose. With the clutch engaged, getting that nut off is pretty easy. You may need to grab one of the pulleys to keep the whole belt from spinning. Be careful not to let the pins/clips touch while you're digging around down there. Ask me how I know.
    IMG_20170723_133104.jpg
    2010-11-29_200450_trail_blazer_underhood_fuse_box.gif

    With the nut off, use the flat blade screwdriver to gently pry the clutch plate off of the clutch. It'll look like this when you're done. On that shaft is a thin washer. Use a pick to get it off of there. Mine was stubborn. Yours may have more than one shim, but mine only had one.
    IMG_20170723_133047.jpg

    Here are a couple pictures of the clutch plate. That's the shim I took out sitting on the plate.
    IMG_20170723_133026.jpg
    IMG_20170723_133011.jpg

    Once you have the shim off, slide the plate back onto the shaft (a bit of grease wouldn't hurt), put the nut on finger tight, re-engage the clutch if you need to, and tighten the nut down. Test and celebrate!
     

    Attached Files:

    Last edited: Jul 25, 2017
  2. Matt

    Matt Silver Supporter

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    Thanks for the write up. Mine is great when you start but after maybe 20 minutes the clutch disengages and won't come back on unless I hit it with a screwdriver.

    I was going to replace the low pressure switch but I think I'll try the shim first and see what happens.

    Thanks again.
     
  3. steveO

    steveO Well-Known Member

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    Removing the shim, if it works, is only a temporary fix. The clutch surfaces will grind as you can see in the photos (center area) and make engagment less reliable. That grinding will eventually scar the entire clutch surface. Is the engagment positive or does it grind and slip to full engagement.
    Check the condition of the hub bearing with the belt off, it may be the problem. Having fixed this issue a couple of times ...the bearing was the main cause. If you replace the bearing you can save the cluch surfaces otherwise the clutch will end up needing replacement .

    The low pressure switch is easy to access but if you always loose the clutch engagement after it runs for 20 min i doubt that is the problem. Inspect the connector on the switch and reseat it.
     
    Last edited: Jul 24, 2017
    Matt likes this.
  4. jsheahawk

    jsheahawk Well-Known Member

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    If it lasts a few years, I figure I got my money out of the repair. :2thumbsup:

    It would be nice if they sold the clutch separate from the compressor.
     
    Tiggerr likes this.
  5. Mooseman

    Mooseman Moderator

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    When I did it on the '02, it lasted 6 years. YMMV.

    BTW, a much easier way to engage the clutch would be to jump the relay.

    Added this to the FAQ.
     
    Mounce likes this.
  6. jsheahawk

    jsheahawk Well-Known Member

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    Fingers crossed.

    That would have been way easier. I updated the OP.

    I've hit the big time now! :dance:
     
    Tiggerr and $ Khalid ! 9130 like this.
  7. $ Khalid ! 9130

    $ Khalid ! 9130 Well-Known Member

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    Great write up @jsheahawk. And i gotta comment on that sick engine bay. Any links to how you got it looking like that.

    Back on took what exactly were the symptoms you were experiencing with the air conditioning?

    Thanks
     
  8. jsheahawk

    jsheahawk Well-Known Member

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    I may have stolen that picture from the internet. To the person who owns that engine bay: Thanks and it's lovely.

    I was having the common issue of the AC working perfectly for a while then suddenly quitting while driving. It would also not cool at idle. I'm assuming that was because the clutch was slipping.

    Here's a good video from realfixesrealfast on how the AC clutch works.

     
    $ Khalid ! 9130 likes this.
  9. $ Khalid ! 9130

    $ Khalid ! 9130 Well-Known Member

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    Ah I see it looks gorgeous though. I have a friend of mine who also owns a trailblazer and is experiencing similar problems. Thought I'd ask for him. Thanks :2thumbsup:
     

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