| [GMCnet] GMC A/C [message #364905] |
Tue, 22 June 2021 16:38  |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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I finally got around to testing the GMC's A/C just now. It had been so
long since I'd touched one that I'd almost forgotten the little I once
knew. But, after I wired up a way to remotely control the compressor
clutch, I connected the manifold set, including a can of Duracool. When I
cranked the engine and opened the low side manifold valve to the Duracool,
the low gauges went to about 90 psi -- and essentially stayed there no
matter what I did. No change on the high side. Until I let Duracool
pressure into the high side, then it went 90 psi and stayed there. After
that, engaging and disengaging the compressor had no effect on either side
-- and I could see the compressor shaft turning. Bleeding pressure from
the low side had no effect on the high side.
I didn't fill the system with Duracool since the compressor didn't seem to
be doing anything. Perhaps I should have added 3 cans?
Unless I'm badly mistaken, I need a replacement compressor, but I'm
certainly open to suggestions!
Ken H.
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| [GMCnet] Re: GMC A/C [message #364924 is a reply to message #364908] |
Wed, 23 June 2021 11:11  |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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Matt,
I just went out and checked: Yes, with the engine cold, I can turn the
compressor shaft by hand, either direction. It's "not hard, not easy"
tight.
I was able to find the almost-obliterated label, remove, restore, and
photograph it. Much to my surprise, it IS a Sanden, not a clone. SD508
Model 5411. I even have its serial number! There are now numerous clones
of it available, and Sanden has a direct replacement, so if necessary, I
should be able to replace it easily.
Ken H.
On Tue, Jun 22, 2021 at 7:35 PM Matt Colie wrote:
> Ken,
>
> Just be clear.
> You could see the compressor shaft turning and the high and low pressures
> did not change??
>
> If it is still an A6 Delco pump, that just can't happen unless shaft is
> broken inside or the entire guts have been ripped out of the pump......
> Just for grins, with things shut down, try turning the drive plate on the
> front of the compressor by hand and see if you feel any resistance at all.
>
>
> I would love to know what happened. I am witnessed some A6 in real bad
> shape, but never that bad.
>
> Matt
> --
> Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL,
> GMCES
> Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum
> Brakes with Applied Control Arms
> SE Michigan - Near DTW - Twixt A2 and Detroit
> _______________________________________________
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: [GMCnet] Re: GMC A/C [message #364925 is a reply to message #364924] |
Wed, 23 June 2021 11:56 |
roy1
Messages: 2126
Registered: July 2004
Location: Minden nevada
Karma: 6
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Senior Member |
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I would say your valves are not seating (stuck open?) a broken crankshaft or a broken rod. At any rate the compressor has a bad mechanical problem.
Roy Keen
Minden,NV
76 X Glenbrook
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