[GMCnet] Height Control Valve

[Roger P. Gleason]

I spent yesterday adjusting a ride height control valve according to the procedure in the GMC maintenance manual. Now that I have figured out what is going on with the valve I want to build a fixture to adjust the valve with. To build the fixture I need a sacrificial valve to build the fixture around. If it is available I also need the arm that goes from the valve to the swing arm.
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[Bob de Kruyff]

mechanical or electronic?
--
Bob de Kruyff
78 Eleganza
Chandler, AZ

[Roger P. Gleason]

The mechanical one mounted in the wheel well.

[Rob Mueller]

Roger,

What year is your coach?

Regards,
Rob Mueller
Sydney, Australia
AUS '75 Avion-The Blue Streak TZE365V100428
USA '75 Avion-Double Trouble TZE365V100426

[Roger P. Gleason]

1976

Iknow the same valve was used on the original design, electro-level I, and I have worked on an electro-level II that still had the same heigth valve.

[Rob Mueller]

Roger,

Thanks, I don't have access to Electro Level valves.

Regards,
Rob Mueller
Sydney, Australia
AUS '75 Avion-The Blue Streak TZE365V100428
USA '75 Avion-Double Trouble TZE365V100426

-----Original Message-----
From: gmclist...@temp.gmcnet.org
[mailto:gmclist...@temp.gmcnet.org] On Behalf Of Roger P. Gleason
Sent: Friday, 13 November 2009 12:18 AM
To: gmc...@temp.gmcnet.org
Subject: Re: [GMCnet] Height Control Valve

[Steven Ferguson]

Roger,
Not to get off track, but it is very difficult if your ride height
settings are way off. Slotting holes, redrilling etc. The adjustable
arms that Applied GMC sells are the way to go. Turn buckles on each
end and adjustment is as easy as loosening the lock nut and turning
the shaft. They are connected on each end with heim joints. Sure
takes the aggravation out of that task.

--
Steve Ferguson
'76 EII
Sierra Vista, AZ
Urethane bushing source
www.bdub.net/ferguson/

[Mike Miller]

rgleas wrote on Thu, 12 November 2009 05:17
> 1976
>
> I know the same valve was used on the original design, electro-level I, and I have worked on an electro-level II that still had the same heigth valve.

Actually 1973 to the early '76's had "POWER LEVEL" systems. During 1976 they changed to the Electro-Level system. It had electrical switches on the dash(76) or side panel(77/78) but the same valve in the wheel well. Starting in mid 1978, they put in the Electro-Level II system with electric sensors and no tank, but two pumps.

But from reading your posts... I think you want a wheel well valve from any GMC except the electric (EL II) one.
--
Mike Miller
`73 26' X Painted D.
`78 23' Birchaven
Hillsboro, OR

[Roger P. Gleason]

What I have found on the control valve I work on is that it was completly out of adjustment the fill valve was opening at the same time as the exhaust port. The 70's was real poor years for Detroit and I suspect that they were not adjusted correctly from the factory. I believe with a fixture they will be very easy to adjust. Also I don't think re-drilling or a turn buckle would be necessary if the valve worked correctly.

The only difficult part of the adjustment procedure is the fluid. No one seems to know where to find it. With a fixture I don't think I will need to remove the fluid.

[Rob Allen]

rgleas wrote on Thu, 12 November 2009 16:34

> The only difficult part of the adjustment procedure is the fluid. No one seems to know where to find it. With a fixture I don't think I will need to remove the fluid.

As I recall, this is a special viscosity silicone fluid, and very hard if not impossible to come by now. One of the Canadian vendors (I think) had some, and did rebuilds of the original valves. Haven't seen anything about it lately. Some one else may recall the name, or details.

--
Rob Allen
'76 x-PB

[Russ Harms]

Rob,
I have a gallon of the stuff
http://www.gmcmhphotos.com/photos/showphoto.php?photo=3827
I would be happy to get rid of some or all of it.

Russ Harms
Medicine Hat, Alberta
78 Royale

----- Original Message -----
From: "Rob Allen" <prof...@camasnet.com>
To: <gmc...@temp.gmcnet.org>
Sent: Thursday, November 12, 2009 7:41 PM
Subject: Re: [GMCnet] Height Control Valve

>
>

[John Wright]

This is the same stuff by the same people that Dave Lenzi uses when he
rebuilds the units. He has all the jigs and fixtures and test setup
to rebuild these valves correctly. For the price he charges you
cannot afford to do it yourself. The price is typically exchange on
the valves and is about $70.

J.R. Wright

[Jim Kanomata]

You can also aquire identical new ones from us for more $.

--
Jim Kanomata
Applied/GMC, Fremont,CA
ji...@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502

[Roger P. Gleason]

I know that you carry them and that is my backup. I do value you as a supplier and have turned to you as a resource on many occasions.
The GMC community I live in don't seem to want to spend money on anything. Then they complain that they do not drive right. As I am sure, you are aware the height control valve is an integral piece of the handling of the coach. What I found after tearing one apart was that it was simply out of adjustment. A adjustment device will go a long way to quieting complaints.

As the quality in Detroit in the 70's was not what it should have been I suspect the adjustment was not correct in the first place since the biggest problem with this design would be water and this unit never had water in it. I also used the original shrader valves.

I also have found a valve to use to make the adjustment device.