[GMCnet] Front dash A/C issues [message #319357] |
Tue, 20 June 2017 20:22 |
BobDunahugh
Messages: 2465 Registered: October 2010 Location: Cedar Rapids, IA
Karma: 11
|
Senior Member |
|
|
Leaky compressor issue solved. I got a Sanden compressor from Applied. Very nice, and simple to install. I flushed it, and put in Oil for R-12. ( got lots of R-12 ) Replaced all electrical components. Now that all works nicely. Next the vacuum components. Nothing works. Is the major problem generally the vacuum valve in the dash control? Then there's the 5 I think diaphragms. It's a 1978 GMC. Bob Dunahugh
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
|
|
|
|
Re: [GMCnet] Front dash A/C issues [message #319359 is a reply to message #319357] |
Tue, 20 June 2017 21:17 |
C Boyd
Messages: 2629 Registered: April 2006
Karma: 18
|
Senior Member |
|
|
The 78 (9) port control valve is available from Jim K for ~ $40. I got the 2 port valve for the heater shut off to clean up and seal.
BobDunahugh wrote on Tue, 20 June 2017 21:22Leaky compressor issue solved. I got a Sanden compressor from Applied. Very nice, and simple to install. I flushed it, and put in Oil for R-12. ( got lots of R-12 ) Replaced all electrical components. Now that all works nicely. Next the vacuum components. Nothing works. Is the major problem generally the vacuum valve in the dash control? Then there's the 5 I think diaphragms. It's a 1978 GMC. Bob Dunahugh
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
C. Boyd
76 Crestmont
East Tennessee
|
|
|
|
Re: [GMCnet] Front dash A/C issues [message #319362 is a reply to message #319357] |
Tue, 20 June 2017 21:59 |
JohnL455
Messages: 4447 Registered: October 2006 Location: Woodstock, IL
Karma: 12
|
Senior Member |
|
|
Usually--- the loss of vacuum is a failed hose in the underhood area due to the harsh environment. Easy to trace. I bet once you have vacuum it works. No vacuum it defaults to DEF for safety readins.
John Lebetski
Woodstock, IL
77 Eleganza II
|
|
|
|
Re: [GMCnet] Front dash A/C issues [message #319383 is a reply to message #319382] |
Wed, 21 June 2017 09:58 |
James Hupy
Messages: 6806 Registered: May 2010
Karma: -62
|
Senior Member |
|
|
Bob, the vacuum motors open and close flappers in the ducting. On the edges
of the flaps, there was originally a felt like piece of material that
closed off the ducts. Probably make really good mouse nesting materials. My
guess anyway. They are kind of a bugger to get to, but a hand vacuum pump
can easily test the dash pots to see if the diaphragms will still move and
hold the flappers. Stuff never ends, does it?
Jim Hupy
Salem, Or
78 GMC ROYALE 403
On Jun 21, 2017 7:51 AM, "Bob Dunahugh" wrote:
> Thanks Gary for the info. But I Think the 78 is different then the 76. (
> Note. I think.) And I know that the default is to defrost. But it just has
> vent only. I need to start pulling covers off. Might be a mouse thing. Let
> you know. Bob Dunahugh
>
>
> ________________________________
> From: Bob Dunahugh
> Sent: Tuesday, June 20, 2017 8:22 PM
> To: gmclist@list.gmcnet.org
> Subject: Front dash A/C issues
>
>
> Leaky compressor issue solved. I got a Sanden compressor from Applied.
> Very nice, and simple to install. I flushed it, and put in Oil for R-12. (
> got lots of R-12 ) Replaced all electrical components. Now that all works
> nicely. Next the vacuum components. Nothing works. Is the major problem
> generally the vacuum valve in the dash control? Then there's the 5 I
> think diaphragms. It's a 1978 GMC. Bob Dunahugh
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
|
|
|