| Expansion valve question [message #183630] |
Sat, 08 September 2012 11:15  |
kwharland
Messages: 246
Registered: November 2005
Location: Central Florida
Karma: 0
|
Senior Member |
|
|
I just replaced the expansion valve on my 78 Eleganza II and question if the small tube that connects to the suction side line is supposed to have an '0' ring? Didn't see one in place when removing the old valve but I have a leak and wonder if that might be the source.
And while this system was supposedly professionally converted to 134a many years ago, the old expansion valve still had black 'O' rings. And there's a step-down adapter that has a black sealing ring that's not 'O' shaped but perhaps that's just to due to the age of it. I've replaced it with an 'O' ring, then went back to the original ring but still have the leak.
1978 Eleganza II
[Updated on: Sun, 09 September 2012 08:40] Report message to a moderator |
|
|
|
| Re: Expansion valve question [message #183736 is a reply to message #183630] |
Sun, 09 September 2012 08:44  |
kwharland
Messages: 246
Registered: November 2005
Location: Central Florida
Karma: 0
|
Senior Member |
|
|
Could it be...did I post a question that can't be answered? What other explanation is possible after 164 views and no replies?
All kidding aside, I am surprised not to get a response. I consider this forum the best source of GMC information with many knowledgeable folks ready to share.
Anyway, perhaps this will bump my question back up where someone with the answer sees it. Wishing everyone a great Sunday.
1978 Eleganza II
|
|
|
|
|
|
| Re: [GMCnet] Expansion valve question [message #183738 is a reply to message #183737] |
Sun, 09 September 2012 08:55 |
kwharland
Messages: 246
Registered: November 2005
Location: Central Florida
Karma: 0
|
Senior Member |
|
|
| Mr ERFisher wrote on Sun, 09 September 2012 09:46 |
what was the question?
gene
|
Does the fitting on the end of the small tube from the expansion valve to the suction side line use an 'O' ring?
1978 Eleganza II
|
|
|
|
| Re: [GMCnet] Expansion valve question [message #183748 is a reply to message #183738] |
Sun, 09 September 2012 09:54 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
|
Senior Member |
|
|
Ken, do you have a type 1, or a type 2 system? On pages 1-43 and 1-44 of
the 1975-76 manual x-7525, it shows pix of both types and a good
explanation. Generally tapered threads do not require o rings, while on ac
fittings, if there is a formed collar or ring on the matching tubing, an o
ring is fitted. SO, yes is the answer, but. STUFF GETS CHANGED BY REPAIR
TECHS.
JIM Hupy
Salem, OR
78 GMC Royale 403
On Sep 9, 2012 6:55 AM, "Ken Harland" <kwharland@bellsouth.net> wrote:
>
>
> Mr ERFisher wrote on Sun, 09 September 2012 09:46
> > what was the question?
> > gene
>
>
> Does the fitting on the end of the small tube from the expansion valve to
> the suction side line use an 'O' ring?
>
>
>
>
> --
> 1978 Eleganza II
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
|
|
|
|
| Re: [GMCnet] Expansion valve question [message #183752 is a reply to message #183748] |
Sun, 09 September 2012 10:26 |
 |
USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
|
Senior Member |
|
|
Ken / Jim,
I was looking at the Parts Book 78Z page 26-4 Fig. 26-015 Air Conditioning - (Includes Evaporator) (Prior to 1977) when I heard a
BOING and your note below came in.
This figure shows Key 8 - Valve Assy - Expansion; unfortunately it shows it with the inlet and outlet tube attached and nothing
about any O-rings.
Page 26-5 has Figure 26-015H Air Conditioning - (Includes Evaporator) (Eff. W/1977). This figure also lists the expansion valve but
once again nothing about any O-rings.
Guess the answer is - take it apart and see what you find! Let us know so we can annotate our manuals.
Regards,
Rob M.
-----Original Message-----
From: James Hupy
Ken, do you have a type 1, or a type 2 system? On pages 1-43 and 1-44 of
the 1975-76 manual x-7525, it shows pix of both types and a good
explanation. Generally tapered threads do not require o rings, while on ac
fittings, if there is a formed collar or ring on the matching tubing, an o
ring is fitted. SO, yes is the answer, but. STUFF GETS CHANGED BY REPAIR
TECHS.
JIM Hupy
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
|
|
|
|
| Re: Expansion valve question [message #183762 is a reply to message #183630] |
Sun, 09 September 2012 12:38 |
kwharland
Messages: 246
Registered: November 2005
Location: Central Florida
Karma: 0
|
Senior Member |
|
|
James, I believe mine is Type II and it's not tapered threads.
Rob, there was no o-ring on the old expansion valve fitting and I can't see one in the receiving fitting on the suction line....doesn't mean there wasn't one. When I inserted the new fitting, it felt tight going in the first time so I thought perhaps I either damaged the old o-ring or even pushed it up into the opening. When it wouldn't hold vacuum, I pulled it back apart for a closer examination. Unfortunately I can't see any evidence of one with mirror and flashlight so I thought I'd check with the experts!
1978 Eleganza II
|
|
|
|
| Re: Expansion valve question [message #183769 is a reply to message #183630] |
Sun, 09 September 2012 13:41 |
Rick Williams
Messages: 256
Registered: July 2004
Karma: 0
|
Senior Member |
|
|
By mistake, I posted this reply to an old thread on Sanden Compressor conversions. Sorry everyone for resurrecting that old thread.
I rebuilt my 78 air last year. Here is the spec on the expansion valve o ring.
Expansion valve capillary tube o ring
0.176 inside 0.316 outside 0.070 diameter
Auto Value part # STD 24604
Rick Williams
Bliss, Michigan
1978 Eleganza II
|
|
|
|
| Re: Expansion valve question [message #183787 is a reply to message #183769] |
Sun, 09 September 2012 17:07 |
kwharland
Messages: 246
Registered: November 2005
Location: Central Florida
Karma: 0
|
Senior Member |
|
|
Thanks Rick, I'll go get one tomorrow and re-test the system. I'll need to satisfy myself that the old one fell out and isn't somehow jammed up inside.
1978 Eleganza II
|
|
|
|
GMCforum
Search
Help
Register
Login
Home
