AC Clutch Help [message #287437] |
Thu, 17 September 2015 10:44 |
jtfred
Messages: 132 Registered: January 2015 Location: Grand Marais, MN
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The good news is that it is no longer in the 90s with high humidity. The bad news is that I have to work on my AC again.
My dash AC had been working great this summer after I replaced the seal using Larry's tool kit and recharging with Duracool. Driving it this week it wouldn't cool. It appears that the clutch is not engaging. I still have pressure in the system. I have power to the connector and I seem to have good continuity on the ground.
Is there anything else I can check to verify that the clutch is bad? If the clutch is bad, can I just replace the clutch or is it better to just replace the compressor as a unit?
Thanks for your help!
John
Fayetteville, GA
1978 Eleganza 403
John Fredrikson
Grand Marais, MN
1978 Eleganza
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Re: AC Clutch Help [message #287438 is a reply to message #287437] |
Thu, 17 September 2015 11:13 |
Bullitthead
Messages: 1411 Registered: November 2013
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You can replace just the clutch and coil without removing the compressor. Verify defective clutch coil by applying 12 volts and ground directly from the battery using a fused wire. Use a 20 amp fuse in your jumper wire. Disconnect the coil wires from the vehicle harness before you put power on them. If the clutch works with the substitute power supply and ground, then the problem is in the vehicle, not the clutch. If it still won't engage or it blows the fuse, replace the clutch and coil. Use the ground wire terminal on the compressor, not just the compressor body when testing. A process of elimination and substitution.
Terry Kelpien
ASE Master Technician
73 Glacier 260
Smithfield, Va.
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Re: AC Clutch Help [message #287440 is a reply to message #287438] |
Thu, 17 September 2015 11:24 |
jtfred
Messages: 132 Registered: January 2015 Location: Grand Marais, MN
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Bullitthead wrote on Thu, 17 September 2015 12:13You can replace just the clutch and coil without removing the compressor. Verify defective clutch coil by applying 12 volts and ground directly from the battery using a fused wire. Use a 20 amp fuse in your jumper wire. Disconnect the coil wires from the vehicle harness before you put power on them. If the clutch works with the substitute power supply and ground, then the problem is in the vehicle, not the clutch. If it still won't engage or it blows the fuse, replace the clutch and coil. Use the ground wire terminal on the compressor, not just the compressor body when testing. A process of elimination and substitution.
I'll try connecting to the battery to see if I get a different result. Does anyone have a part number of the clutch?
Thanks,
John
John Fredrikson
Grand Marais, MN
1978 Eleganza
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Re: AC Clutch Help [message #287441 is a reply to message #287440] |
Thu, 17 September 2015 11:57 |
roy1
Messages: 2126 Registered: July 2004 Location: Minden nevada
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You could also check it for continuity (ohms). Keep in mind if the air gap is too great it may not pull in with power applied.
Roy Keen
Minden,NV
76 X Glenbrook
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Re: AC Clutch Help [message #287446 is a reply to message #287437] |
Thu, 17 September 2015 15:21 |
jtfred
Messages: 132 Registered: January 2015 Location: Grand Marais, MN
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I tried running power directly to the clutch and got nothing.
I would rather replace the coil or clutch assembly than replace the compressor with a clutch but I am having a hard time finding a replacement clutch assembly part number. Has anyone replaced just the clutch assembly?
Thanks!
John
John Fredrikson
Grand Marais, MN
1978 Eleganza
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Re: AC Clutch Help [message #287448 is a reply to message #287437] |
Thu, 17 September 2015 16:14 |
JohnL455
Messages: 4447 Registered: October 2006 Location: Woodstock, IL
Karma: 12
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Easy, but you need the puller tool and installer tool. May not be room where it lives. You may be able to unbolt the A6 and turn (fold) the snoot to the open hatch to work in it. Also you did the 12V test but check the clutch terminals with Ohm meter. It should be some number (4-10Ohms totally guessing) but not open. See if the coil wire is broken at the terminals. Tug on the ground wire to be sure it is solid and not broken under the insulation. You ran a new test ground right? They rarely fail so rule out all the externals.
John Lebetski
Woodstock, IL
77 Eleganza II
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Re: AC Clutch Help [message #287449 is a reply to message #287446] |
Thu, 17 September 2015 16:25 |
C Boyd
Messages: 2629 Registered: April 2006
Karma: 18
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From under the hood using a long wood handle and bump the clutch and see if it might be stuck some not letting the magnet work.
jtfred wrote on Thu, 17 September 2015 16:21I tried running power directly to the clutch and got nothing.
I would rather replace the coil or clutch assembly than replace the compressor with a clutch but I am having a hard time finding a replacement clutch assembly part number. Has anyone replaced just the clutch assembly?
Thanks!
John
C. Boyd
76 Crestmont
East Tennessee
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Re: [GMCnet] AC Clutch Help [message #287469 is a reply to message #287462] |
Thu, 17 September 2015 21:29 |
jtfred
Messages: 132 Registered: January 2015 Location: Grand Marais, MN
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Thanks Larry. I haven't had much luck verifying a part number for the clutch. I did see a 2013 post by Emery Stora with some part numbers:
"If anyone wants to rebuild their own, the compressor is 57052 ("superheat"),
the clutch is 48276, the hub is 48241, and the coil is 48245. You'll need a
special puller that threads into the hub to pull it off the shaft so unless
you have or can beg, borrow, or steal the puller, you'd probably be better
off getting the complete assembly, 57087."
But haven't been able to track down a source for the part.
Thanks!
John
John Fredrikson
Grand Marais, MN
1978 Eleganza
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Re: AC Clutch Help [message #287475 is a reply to message #287448] |
Thu, 17 September 2015 23:11 |
Ken Burton
Messages: 10030 Registered: January 2004 Location: Hebron, Indiana
Karma: 10
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Since you worked on the front seal recently, you had to remove the clutch to do it. Upon reinstalling it, you needed to set the clearance. I believe it is around .020" . I did not look up this value in the book. If that gap s too wide the clutch might not engage or might be intermittent.
I would first check that you are getting 12 volts to the clutch coil. If OK, I would ohm meter the clutch coil. I then would put 12 volts back on the coil and do what chuck Boyd recommended and tap it with a hammer handle to see if it will engage. All you need is 12 volts across the clutch. The engine does not have to be running to try this.
I would do all of this before I ordered or removed the clutch coil.
I have the compressor seal remover tools but I have run into a snag. I probably will not have time to get the job done before the GMCMI rally next week. I have to take my brother in on Sunday for a leg and foot amputation. The actual amputation will be on Tuesday. He has no immediate family other than Laurie and I so I need to be around here for him and will probably not get the compressor repaired before I leave for GMCMI. If the tools need to be returned quickly let me know and I'll do that and borrow them again later.
Ken
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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Re: AC Clutch Help [message #287480 is a reply to message #287437] |
Fri, 18 September 2015 06:55 |
jtfred
Messages: 132 Registered: January 2015 Location: Grand Marais, MN
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Thanks Ken. I'm sorry to hear about your brother's health issues. We will keep him and your family in our prayers.
I have verified that I do have 12v to the connector and a good ground. I did put an ohm meter on the coil leads and it was within spec, but I can't recall exactly what the reading was. I will verify again when I work on it again.
I will try the hammer handle "test" next to see if I can get it to trigger.
Don't worry about Larry's tool kit. I think I can get a loaner clutch tool at AZ locally.
I'm hoping I can get this fixed without having to drain the system and refill since the double seal I put in seems to still be holding.
Thanks,
John
John Fredrikson
Grand Marais, MN
1978 Eleganza
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Re: AC Clutch Help [message #287500 is a reply to message #287480] |
Fri, 18 September 2015 10:59 |
Bullitthead
Messages: 1411 Registered: November 2013
Karma: 5
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Clutch air gap needs to be less than .040 for operation from my experience. As Ken said, .020 is the right gap. You can get it down to .010, but that allows no room for errors in the clutch parts. The instructions that came with a coil I put on a Cadillac listed .060 as the max air gap, but I would never set one at that and seen several that would still work with that gap, but many of them required a bump from that broomstick or wooden hammer handle to engage. There should have been a package of shims with the replacement clutch.
Terry Kelpien
ASE Master Technician
73 Glacier 260
Smithfield, Va.
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Re: AC Clutch Help [message #287503 is a reply to message #287437] |
Fri, 18 September 2015 11:37 |
habbyguy
Messages: 896 Registered: May 2012 Location: Mesa, AZ
Karma: 3
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In the manual, they list the acceptable range for the gap between the "frictional surfaces" at 0.022" to 0.057". (Note: corrected the numbers thanks to a heads-up from Ken Burton)
It may be possible to re-shim the clutch if the gap is wider than this. Another alternative might be to cheat by placing something between the hub and the outer clutch disc (to push it a little closer to the coil, to allow it to engage easier). I did that on a Volvo V70 that had a too-wide gap, using a bit of wire. 30 minutes, five cents worth of landscaping wire, and I saved a LOT of work and had an A/C that worked like a champ again.
http://volvoforums.com/forum/2001-2013-model-year-v70-55/c-compressor-shim-option-78578/
Mark Hickey
Mesa, AZ
1978 Royale Center Kitchen
[Updated on: Fri, 18 September 2015 18:13] Report message to a moderator
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Re: AC Clutch Help [message #287510 is a reply to message #287480] |
Fri, 18 September 2015 12:51 |
gbarrow2
Messages: 765 Registered: February 2004 Location: Lake Almanor, Ca./ Red Bl...
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Ignore this if it doesn't apply.
Sounds like you have verified that it is not an electrical issue. I assume that verifies that the low pressure switch is operating properly and there is sufficient pressure in the system??
Gene Barrow
Lake Almanor, Ca.
1976 Palm Beach
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Re: AC Clutch Help [message #287522 is a reply to message #287503] |
Fri, 18 September 2015 16:49 |
Ken Burton
Messages: 10030 Registered: January 2004 Location: Hebron, Indiana
Karma: 10
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habbyguy wrote on Fri, 18 September 2015 11:37In the manual, they list the acceptable range for the gap between the "frictional surfaces" at 0.22" to 0.57".
It may be possible to re-shim the clutch if the gap is wider than this. Another alternative might be to cheat by placing something between the hub and the outer clutch disc (to push it a little closer to the coil, to allow it to engage easier). I did that on a Volvo V70 that had a too-wide gap, using a bit of wire. 30 minutes, five cents worth of landscaping wire, and I saved a LOT of work and had an A/C that worked like a champ again.
http://volvoforums.com/forum/2001-2013-model-year-v70-55/c-compressor-shim-option-78578/
Mark, I'm not trying to nit pick here but shouldn't those clearance numbers have a zero in front of them? (.022" to .057") I still have not looked them up but without the zero in front, those number seem very large.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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Re: AC Clutch Help [message #287530 is a reply to message #287437] |
Fri, 18 September 2015 18:12 |
habbyguy
Messages: 896 Registered: May 2012 Location: Mesa, AZ
Karma: 3
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Ken, mea culpa... I did mis-type the numbers (and yes, it would be a SERIOUSLY powerful electromagnetic clutch that could close a 6/10th of an inch gap!!!). I'll edit my original post to reflect the right numbers to avoid confusion in the future... Thanks for the catch!
Mark Hickey
Mesa, AZ
1978 Royale Center Kitchen
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