Air suspension and leveling system

[nathan blythe]

Hello everyone, this is my first post on this forum so please correct me if this is the wrong place to post. Thanks!
I recently bought a 1973 gmc motor home with the 455 olds motor. It had not run since 1994, so I changed all fluids and the battery and started it up.
However, the air suspension would not raise the back of the motor home. So I drove it home at about 10mph. The air suspension is the first thing I
would like to fix, but I am not sure where to start. Any advice would be greatly appreciated. (I tried to use the leveling controls to raise the back,
but that did not chance anything)
Thanks
Nathan

 

[wally anderson]

> Hello everyone, this is my first post on this forum so please correct me if this is the wrong place to post. Thanks!
> I recently bought a 1973 gmc motor home with the 455 olds motor. It had not run since 1994, so I changed all fluids and the battery and started it
> up. However, the air suspension would not raise the back of the motor home. So I drove it home at about 10mph. The air suspension is the first thing
> I would like to fix, but I am not sure where to start. Any advice would be greatly appreciated. (I tried to use the leveling controls to raise the
> back, but that did not chance anything)
> Thanks
> Nathan

Welcome aboard Nathan!
Here are some links describing our power level system.
http://www.gmceast.com/technical/Denney_Power_Level_System.pdf
http://www.gmceast.com/technical/Denney_Power_Level_System.pdf
and
http://www.bdub.net/GMC_Power_Level_Air_Suspension_Systems.pdf
http://www.bdub.net/GMC_Power_Level_Air_Suspension_Systems.pdf
These should get you going. Does the compressor run and do you have pressure in the tank?
--
Wally Anderson
Omaha NE
75 Glenbrook
Megasquirt III injection
Bob Stone hydroBOOOOST
Manny reaction arm system
Branscombe Kelsey Hayes park brake
http://wallyandsue.blogspot.com/

 

[Jim Hupy]

RTFM. if you have one. If not, find one and spend some time reading it. You
will get the exact information, without prejudice or imbellishments or
outright WRONG INFORMATION. Then you will be prepared for the onslaught of
information you are about to receive. 73's and 74's are unique and a bit
quirky, but when all is well, they do work.
Jim Hupy
Salem, Or
78 GMC ROYALE 403

> > Hello everyone, this is my first post on this forum so please correct me
> if this is the wrong place to post. Thanks!
> > I recently bought a 1973 gmc motor home with the 455 olds motor. It had
> not run since 1994, so I changed all fluids and the battery and started it
> > up. However, the air suspension would not raise the back of the motor
> home. So I drove it home at about 10mph. The air suspension is the first
> thing
> > I would like to fix, but I am not sure where to start. Any advice would
> be greatly appreciated. (I tried to use the leveling controls to raise the
> > back, but that did not chance anything)
> > Thanks
> > Nathan
>
> Welcome aboard Nathan!
> Here are some links describing our power level system.
> http://www.gmceast.com/technical/Denney_Power_Level_System.pdf
> http://www.gmceast.com/technical/Denney_Power_Level_System.pdf
> and
> http://www.bdub.net/GMC_Power_Level_Air_Suspension_Systems.pdf
> http://www.bdub.net/GMC_Power_Level_Air_Suspension_Systems.pdf
> These should get you going. Does the compressor run and do you have
> pressure in the tank?
> --
> Wally Anderson
> Omaha NE
> 75 Glenbrook
> Megasquirt III injection
> Bob Stone hydroBOOOOST
> Manny reaction arm system
> Branscombe Kelsey Hayes park brake
> http://wallyandsue.blogspot.com/
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

 

[Matt Colie]

> Hello everyone, this is my first post on this forum so please correct me if this is the wrong place to post. Thanks!
> I recently bought a 1973 gmc motor home with the 455 olds motor. It had not run since 1994, so I changed all fluids and the battery and started it
> up. However, the air suspension would not raise the back of the motor home. So I drove it home at about 10mph. The air suspension is the first thing
> I would like to fix, but I am not sure where to start. Any advice would be greatly appreciated. (I tried to use the leveling controls to raise the
> back, but that did not chance anything)
> Thanks
> Nathan

Nathan,

Welcome to the group, family, cult, asylum....

This is the RIGHT place to post questions. If you scroll down, you will find that I still am, and I have owned our coach for 12 years and 60K+
miles.

Finding your way here was the very best thing that you could do. This is an uncommon community of owners that want to see you enjoy what your coach
can do for you as much as we all know it can. Just be aware that this is a 44 year old "truck" (it isn't a truck chassis) with a 44 year old cabin on
it that has been though a multi-decade earthquake. It will require maintenance, but if you keep up with that maintenance, she can be reliable. In
fact, she can be as reliable as anything just off the dealer lot.

Now, about the air suspension. It you digest the two papers that Wally pointed you to, you will learn virtually all you need to know to make it work
correctly. Until you have it at least nearly functional, do not buy any parts you do not need. The basic system's weak point (imho) is the
compressor. The second, and you have to have a compressor to find it is the body joint in the control valves. This joint is made with a
cork/composite gasket that is wrong for the application. (I have a fix that works if the gasket is not damaged.) When you get pressure in the system
and have the valves pulled out, check that joint early in the game. When you learn enough to frame a question, bring it back here. You will get a
good answer.

If you have not downloaded the documentation from Bdub's, this would be a good time. You particularly need manual X7425. Your coach is a 73-23 and
there is a lot about it that was changed for later (that are covered in the X7525 manual). Believe me when I tell you this (read my sigfile).

Well, here is a part that I like a lot. You have just become a member of an amazing community. These people will be an unbelievable resource. To
aid this, please build a useful sigfile. Go to and scroll down to the signiture box. Fill in your name, a bit about
the coach, and a geographic reference. This is all needed so, we know who we talked to, what is special about the coach and if you are in striking
range for someone that wants to help.

This supportive and helping community so like that of the watermen of my world that I have taken to welcoming any that arrive here much as a new owner
or vessel is welcomed there just because I feel it is fitting. So,

May the Good Lord bless this coach and all those that set forth within her.

Welcome Nathan

Matt

--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Still Loving OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit

 

[burt and faye curtis]

Friend had a 73 in which the compressor does not shut off. I am suspecting
that the pressure switch either is not hooked up or is not working. Her
coach is using the Dana compressor which is not the one shown in the early
73 workshop manual and is up in front of driver's wheel area.
Would anyone know where to start looking for the pressure switch? Oh, there
seems to be no air leaks, so don't believe that is why it keeps running.
Nice article from Eastern States, but like the workshop manual, it doesn't
address a compressor that just won't stop.

Thanks in advance.

Fay Curtis
76 Glenbrook that had same problem, but has electrolevel 1 system
Kneeland, Ca

> > Hello everyone, this is my first post on this forum so please correct me
> if this is the wrong place to post. Thanks!
> > I recently bought a 1973 gmc motor home with the 455 olds motor. It had
> not run since 1994, so I changed all fluids and the battery and started it
> > up. However, the air suspension would not raise the back of the motor
> home. So I drove it home at about 10mph. The air suspension is the first
> thing
> > I would like to fix, but I am not sure where to start. Any advice would
> be greatly appreciated. (I tried to use the leveling controls to raise the
> > back, but that did not chance anything)
> > Thanks
> > Nathan
>
> Nathan,
>
> Welcome to the group, family, cult, asylum....
>
> This is the RIGHT place to post questions. If you scroll down, you will
> find that I still am, and I have owned our coach for 12 years and 60K+
> miles.
>
> Finding your way here was the very best thing that you could do. This is
> an uncommon community of owners that want to see you enjoy what your coach
> can do for you as much as we all know it can. Just be aware that this is
> a 44 year old "truck" (it isn't a truck chassis) with a 44 year old cabin on
> it that has been though a multi-decade earthquake. It will require
> maintenance, but if you keep up with that maintenance, she can be
> reliable. In
> fact, she can be as reliable as anything just off the dealer lot.
>
> Now, about the air suspension. It you digest the two papers that Wally
> pointed you to, you will learn virtually all you need to know to make it
> work
> correctly. Until you have it at least nearly functional, do not buy any
> parts you do not need. The basic system's weak point (imho) is the
> compressor. The second, and you have to have a compressor to find it is
> the body joint in the control valves. This joint is made with a
> cork/composite gasket that is wrong for the application. (I have a fix
> that works if the gasket is not damaged.) When you get pressure in the
> system
> and have the valves pulled out, check that joint early in the game. When
> you learn enough to frame a question, bring it back here. You will get a
> good answer.
>
> If you have not downloaded the documentation from Bdub's, this would be a
> good time. You particularly need manual X7425. Your coach is a 73-23 and
> there is a lot about it that was changed for later (that are covered in
> the X7525 manual). Believe me when I tell you this (read my sigfile).
>
> Well, here is a part that I like a lot. You have just become a member of
> an amazing community. These people will be an unbelievable resource. To
> aid this, please build a useful sigfile. Go to Settings> and scroll down to the signiture box. Fill in your name, a bit
> about
> the coach, and a geographic reference. This is all needed so, we know who
> we talked to, what is special about the coach and if you are in striking
> range for someone that wants to help.
>
> This supportive and helping community so like that of the watermen of my
> world that I have taken to welcoming any that arrive here much as a new
> owner
> or vessel is welcomed there just because I feel it is fitting. So,
>
> May the Good Lord bless this coach and all those that set forth within her.
>
> Welcome Nathan
>
> Matt
>
> --
> Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
> Still Loving OE Rear Drum Brakes with Applied Control Arms
> SE Michigan - Twixt A2 and Detroit
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

 

[Ken B]

Before you get in to it too far make sure that someone did not install aftermarket shutoff valves on the air bags. These were not GM installed and
will not be mentioned in any manual. After that, find out if he compressor is running and if there is any pressure in the tank.

--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana

 

[steve adams]

Nathan,
A big GMC welcome to you. You have found the right place for good technical assistance. Between the manuals and the experts here you should be able
to troubleshoot all systems. For the rear air suspension, many have installed manual shut off valves near the air bags, with schrader air valves so
you can air the bags up with any standard air compressor or air hose at a service station. That would at least test the ability for the bags to hold
air and allow you to travel or move the coach while you troubleshoot the rest of the system. check near the air bags to see if you already have them,
if not they are available on-line at Applied GMC.
--
1978 GMC Royal
Eastern Pennslyvania
1968 Chevrolet C20 396 Camper Special
1969 Chevrolet C20 Camper Special
1985 Buick Electra Park Avenue
1992 Camaro 25th Anniversary Heretage Edition Black

 

[bdub]

http://www.bdub.net/GMCLinks.html

http://www.bdub.net/manuals/index.html

http://www.bdub.net/GMCSupplierLinks.html

On Jun 18, 2017 9:47 AM, "Nathan Blythe"
wrote:

> Hello everyone, this is my first post on this forum so please correct me
> if this is the wrong place to post. Thanks!
> I recently bought a 1973 gmc motor home with the 455 olds motor. It had
> not run since 1994, so I changed all fluids and the battery and started it
> up.
> However, the air suspension would not raise the back of the motor home. So
> I drove it home at about 10mph. The air suspension is the first thing I
> would like to fix, but I am not sure where to start. Any advice would be
> greatly appreciated. (I tried to use the leveling controls to raise the
> back,
> but that did not chance anything)
> Thanks
> Nathan
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

 

[gworobec]

On my 73 the pressure switch is viewable on the drivers side as you open the front drivers side hatch. Probably about a foot in.

>
> Friend had a 73 in which the compressor does not shut off. I am suspecting
> that the pressure switch either is not hooked up or is not working. Her
> coach is using the Dana compressor which is not the one shown in the early
> 73 workshop manual and is up in front of driver's wheel area.
> Would anyone know where to start looking for the pressure switch? Oh, there
> seems to be no air leaks, so don't believe that is why it keeps running.
> Nice article from Eastern States, but like the workshop manual, it doesn't
> address a compressor that just won't stop.
>
> Thanks in advance.
>
> Fay Curtis
> 76 Glenbrook that had same problem, but has electrolevel 1 system
> Kneeland, Ca
>

>

>>> Hello everyone, this is my first post on this forum so please correct me
>> if this is the wrong place to post. Thanks!
>>> I recently bought a 1973 gmc motor home with the 455 olds motor. It had
>> not run since 1994, so I changed all fluids and the battery and started it
>>> up. However, the air suspension would not raise the back of the motor
>> home. So I drove it home at about 10mph. The air suspension is the first
>> thing
>>> I would like to fix, but I am not sure where to start. Any advice would
>> be greatly appreciated. (I tried to use the leveling controls to raise the
>>> back, but that did not chance anything)
>>> Thanks
>>> Nathan
>>
>> Nathan,
>>
>> Welcome to the group, family, cult, asylum....
>>
>> This is the RIGHT place to post questions. If you scroll down, you will
>> find that I still am, and I have owned our coach for 12 years and 60K+
>> miles.
>>
>> Finding your way here was the very best thing that you could do. This is
>> an uncommon community of owners that want to see you enjoy what your coach
>> can do for you as much as we all know it can. Just be aware that this is
>> a 44 year old "truck" (it isn't a truck chassis) with a 44 year old cabin on
>> it that has been though a multi-decade earthquake. It will require
>> maintenance, but if you keep up with that maintenance, she can be
>> reliable. In
>> fact, she can be as reliable as anything just off the dealer lot.
>>
>> Now, about the air suspension. It you digest the two papers that Wally
>> pointed you to, you will learn virtually all you need to know to make it
>> work
>> correctly. Until you have it at least nearly functional, do not buy any
>> parts you do not need. The basic system's weak point (imho) is the
>> compressor. The second, and you have to have a compressor to find it is
>> the body joint in the control valves. This joint is made with a
>> cork/composite gasket that is wrong for the application. (I have a fix
>> that works if the gasket is not damaged.) When you get pressure in the
>> system
>> and have the valves pulled out, check that joint early in the game. When
>> you learn enough to frame a question, bring it back here. You will get a
>> good answer.
>>
>> If you have not downloaded the documentation from Bdub's, this would be a
>> good time. You particularly need manual X7425. Your coach is a 73-23 and
>> there is a lot about it that was changed for later (that are covered in
>> the X7525 manual). Believe me when I tell you this (read my sigfile).
>>
>> Well, here is a part that I like a lot. You have just become a member of
>> an amazing community. These people will be an unbelievable resource. To
>> aid this, please build a useful sigfile. Go to > Settings> and scroll down to the signiture box. Fill in your name, a bit
>> about
>> the coach, and a geographic reference. This is all needed so, we know who
>> we talked to, what is special about the coach and if you are in striking
>> range for someone that wants to help.
>>
>> This supportive and helping community so like that of the watermen of my
>> world that I have taken to welcoming any that arrive here much as a new
>> owner
>> or vessel is welcomed there just because I feel it is fitting. So,
>>
>> May the Good Lord bless this coach and all those that set forth within her.
>>
>> Welcome Nathan
>>
>> Matt
>>
>> --
>> Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
>> Still Loving OE Rear Drum Brakes with Applied Control Arms
>> SE Michigan - Twixt A2 and Detroit
>>
>> _______________________________________________
>> 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

Gary Worobec
garytwmw
(o) 951-763-0518
(cell) 773-230-6226

 

[burt and faye curtis]

Thanks Gary. Will take a look there. Could you maybe post a picture of what
yours looks like?

Fay Curtis
76 Glenbrook
Kneeland, Ca

> On my 73 the pressure switch is viewable on the drivers side as you open
> the front drivers side hatch. Probably about a foot in.
>
>
> > On Jun 18, 2017, at 9:32 AM, Burt and Faye curtis <

> >
> > Friend had a 73 in which the compressor does not shut off. I am
> suspecting
> > that the pressure switch either is not hooked up or is not working. Her
> > coach is using the Dana compressor which is not the one shown in the
> early
> > 73 workshop manual and is up in front of driver's wheel area.
> > Would anyone know where to start looking for the pressure switch? Oh,
> there
> > seems to be no air leaks, so don't believe that is why it keeps running.
> > Nice article from Eastern States, but like the workshop manual, it
> doesn't
> > address a compressor that just won't stop.
> >
> > Thanks in advance.
> >
> > Fay Curtis
> > 76 Glenbrook that had same problem, but has electrolevel 1 system
> > Kneeland, Ca
> >
> > On Sunday, June 18, 2017, Matt Colie >

> >>> Hello everyone, this is my first post on this forum so please correct
> me
> >> if this is the wrong place to post. Thanks!
> >>> I recently bought a 1973 gmc motor home with the 455 olds motor. It had
> >> not run since 1994, so I changed all fluids and the battery and started
> it
> >>> up. However, the air suspension would not raise the back of the motor
> >> home. So I drove it home at about 10mph. The air suspension is the first
> >> thing
> >>> I would like to fix, but I am not sure where to start. Any advice would
> >> be greatly appreciated. (I tried to use the leveling controls to raise
> the
> >>> back, but that did not chance anything)
> >>> Thanks
> >>> Nathan
> >>
> >> Nathan,
> >>
> >> Welcome to the group, family, cult, asylum....
> >>
> >> This is the RIGHT place to post questions. If you scroll down, you will
> >> find that I still am, and I have owned our coach for 12 years and 60K+
> >> miles.
> >>
> >> Finding your way here was the very best thing that you could do. This
> is
> >> an uncommon community of owners that want to see you enjoy what your
> coach
> >> can do for you as much as we all know it can. Just be aware that this
> is
> >> a 44 year old "truck" (it isn't a truck chassis) with a 44 year old
> cabin on
> >> it that has been though a multi-decade earthquake. It will require
> >> maintenance, but if you keep up with that maintenance, she can be
> >> reliable. In
> >> fact, she can be as reliable as anything just off the dealer lot.
> >>
> >> Now, about the air suspension. It you digest the two papers that Wally
> >> pointed you to, you will learn virtually all you need to know to make it
> >> work
> >> correctly. Until you have it at least nearly functional, do not buy any
> >> parts you do not need. The basic system's weak point (imho) is the
> >> compressor. The second, and you have to have a compressor to find it is
> >> the body joint in the control valves. This joint is made with a
> >> cork/composite gasket that is wrong for the application. (I have a fix
> >> that works if the gasket is not damaged.) When you get pressure in the
> >> system
> >> and have the valves pulled out, check that joint early in the game.
> When
> >> you learn enough to frame a question, bring it back here. You will get
> a
> >> good answer.
> >>
> >> If you have not downloaded the documentation from Bdub's, this would be
> a
> >> good time. You particularly need manual X7425. Your coach is a 73-23
> and
> >> there is a lot about it that was changed for later (that are covered in
> >> the X7525 manual). Believe me when I tell you this (read my sigfile).
> >>
> >> Well, here is a part that I like a lot. You have just become a member
> of
> >> an amazing community. These people will be an unbelievable resource.
> To
> >> aid this, please build a useful sigfile. Go to >> Settings> and scroll down to the signiture box. Fill in your name, a
> bit
> >> about
> >> the coach, and a geographic reference. This is all needed so, we know
> who
> >> we talked to, what is special about the coach and if you are in striking
> >> range for someone that wants to help.
> >>
> >> This supportive and helping community so like that of the watermen of my
> >> world that I have taken to welcoming any that arrive here much as a new
> >> owner
> >> or vessel is welcomed there just because I feel it is fitting. So,
> >>
> >> May the Good Lord bless this coach and all those that set forth within
> her.
> >>
> >> Welcome Nathan
> >>
> >> Matt
> >>
> >> --
> >> Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
> >> Still Loving OE Rear Drum Brakes with Applied Control Arms
> >> SE Michigan - Twixt A2 and Detroit
> >>
> >> _______________________________________________
> >> 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
>
> Gary Worobec
> garytwmw
> (o) 951-763-0518
> (cell) 773-230-6226
>
>
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

 

[gworobec]

Faye, I replaced all of my air stuff a couple of years ago so my pressure switch, compressor and tank are all relocated however I’m sure someone out there can snap a photo of an OEM system for you.

>
> Thanks Gary. Will take a look there. Could you maybe post a picture of what
> yours looks like?
>
> Fay Curtis
> 76 Glenbrook
> Kneeland, Ca
>

>
>> On my 73 the pressure switch is viewable on the drivers side as you open
>> the front drivers side hatch. Probably about a foot in.
>>
>>
>>> On Jun 18, 2017, at 9:32 AM, Burt and Faye curtis <

>>>
>>> Friend had a 73 in which the compressor does not shut off. I am
>> suspecting
>>> that the pressure switch either is not hooked up or is not working. Her
>>> coach is using the Dana compressor which is not the one shown in the
>> early
>>> 73 workshop manual and is up in front of driver's wheel area.
>>> Would anyone know where to start looking for the pressure switch? Oh,
>> there
>>> seems to be no air leaks, so don't believe that is why it keeps running.
>>> Nice article from Eastern States, but like the workshop manual, it
>> doesn't
>>> address a compressor that just won't stop.
>>>
>>> Thanks in advance.
>>>
>>> Fay Curtis
>>> 76 Glenbrook that had same problem, but has electrolevel 1 system
>>> Kneeland, Ca
>>>
>>> On Sunday, June 18, 2017, Matt Colie >>

>>>>> Hello everyone, this is my first post on this forum so please correct
>> me
>>>> if this is the wrong place to post. Thanks!
>>>>> I recently bought a 1973 gmc motor home with the 455 olds motor. It had
>>>> not run since 1994, so I changed all fluids and the battery and started
>> it
>>>>> up. However, the air suspension would not raise the back of the motor
>>>> home. So I drove it home at about 10mph. The air suspension is the first
>>>> thing
>>>>> I would like to fix, but I am not sure where to start. Any advice would
>>>> be greatly appreciated. (I tried to use the leveling controls to raise
>> the
>>>>> back, but that did not chance anything)
>>>>> Thanks
>>>>> Nathan
>>>>
>>>> Nathan,
>>>>
>>>> Welcome to the group, family, cult, asylum....
>>>>
>>>> This is the RIGHT place to post questions. If you scroll down, you will
>>>> find that I still am, and I have owned our coach for 12 years and 60K+
>>>> miles.
>>>>
>>>> Finding your way here was the very best thing that you could do. This
>> is
>>>> an uncommon community of owners that want to see you enjoy what your
>> coach
>>>> can do for you as much as we all know it can. Just be aware that this
>> is
>>>> a 44 year old "truck" (it isn't a truck chassis) with a 44 year old
>> cabin on
>>>> it that has been though a multi-decade earthquake. It will require
>>>> maintenance, but if you keep up with that maintenance, she can be
>>>> reliable. In
>>>> fact, she can be as reliable as anything just off the dealer lot.
>>>>
>>>> Now, about the air suspension. It you digest the two papers that Wally
>>>> pointed you to, you will learn virtually all you need to know to make it
>>>> work
>>>> correctly. Until you have it at least nearly functional, do not buy any
>>>> parts you do not need. The basic system's weak point (imho) is the
>>>> compressor. The second, and you have to have a compressor to find it is
>>>> the body joint in the control valves. This joint is made with a
>>>> cork/composite gasket that is wrong for the application. (I have a fix
>>>> that works if the gasket is not damaged.) When you get pressure in the
>>>> system
>>>> and have the valves pulled out, check that joint early in the game.
>> When
>>>> you learn enough to frame a question, bring it back here. You will get
>> a
>>>> good answer.
>>>>
>>>> If you have not downloaded the documentation from Bdub's, this would be
>> a
>>>> good time. You particularly need manual X7425. Your coach is a 73-23
>> and
>>>> there is a lot about it that was changed for later (that are covered in
>>>> the X7525 manual). Believe me when I tell you this (read my sigfile).
>>>>
>>>> Well, here is a part that I like a lot. You have just become a member
>> of
>>>> an amazing community. These people will be an unbelievable resource.
>> To
>>>> aid this, please build a useful sigfile. Go to >>> Settings> and scroll down to the signiture box. Fill in your name, a
>> bit
>>>> about
>>>> the coach, and a geographic reference. This is all needed so, we know
>> who
>>>> we talked to, what is special about the coach and if you are in striking
>>>> range for someone that wants to help.
>>>>
>>>> This supportive and helping community so like that of the watermen of my
>>>> world that I have taken to welcoming any that arrive here much as a new
>>>> owner
>>>> or vessel is welcomed there just because I feel it is fitting. So,
>>>>
>>>> May the Good Lord bless this coach and all those that set forth within
>> her.
>>>>
>>>> Welcome Nathan
>>>>
>>>> Matt
>>>>
>>>> --
>>>> Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
>>>> Still Loving OE Rear Drum Brakes with Applied Control Arms
>>>> SE Michigan - Twixt A2 and Detroit
>>>>
>>>> _______________________________________________
>>>> 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
>>
>> Gary Worobec
>> garytwmw
>> (o) 951-763-0518
>> (cell) 773-230-6226
>>
>>
>>
>>
>> _______________________________________________
>> 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

Gary Worobec
garytwmw
(o) 951-763-0518
(cell) 773-230-6226

 

[a.]

> Hello everyone, this is my first post on this forum so please correct me if this is the wrong place to post. Thanks!
> I recently bought a 1973 gmc motor home with the 455 olds motor. It had not run since 1994, so I changed all fluids and the battery and started it
> up. However, the air suspension would not raise the back of the motor home. So I drove it home at about 10mph. The air suspension is the first thing
> I would like to fix, but I am not sure where to start. Any advice would be greatly appreciated. (I tried to use the leveling controls to raise the
> back, but that did not chance anything)
> Thanks
> Nathan

First off, check to see if the tires wore through the wheel well liners or otherwise separated the liner from the floor. 73s had wheel wells that
weren't quite tall enough.

As far as the airbags raising and/or leveling, there are lots of things to check. Some have mentioned that people put shut-off valves at the bag.
Check and see if it has them, and if they are in the OFF position.

Then see if the compressor runs. Do that by turning the key to the "Run" position and listen for the compressor. If it doesn't run, check to see if it
has been removed, then check the circuit breaker for the compressor. The circuit breaker is on the fuse block behind the glove compartment.

If the compressor runs, see if it builds up pressure. If not, there might be a massive leak somewhere, or you might need a new compressor.

Report back here after you get that far. Generally, if the compressor runs, and makes a little pressure, and there are no shut off valves in the line,
it will either hiss at a leak, or raise the bags at least a little.

Most important, read this:

http://www.gmceast.com/technical/Denney_Power_Level_System.pdf

 

[Gene Fisher]

Read here
http://bdub.net/gmcmotorhome.info/wireless.html

> > Hello everyone, this is my first post on this forum so please correct me
> if this is the wrong place to post. Thanks!
> > I recently bought a 1973 gmc motor home with the 455 olds motor. It had
> not run since 1994, so I changed all fluids and the battery and started it
> > up. However, the air suspension would not raise the back of the motor
> home. So I drove it home at about 10mph. The air suspension is the first
> thing
> > I would like to fix, but I am not sure where to start. Any advice would
> be greatly appreciated. (I tried to use the leveling controls to raise the
> > back, but that did not chance anything)
> > Thanks
> > Nathan
>
> First off, check to see if the tires wore through the wheel well liners or
> otherwise separated the liner from the floor. 73s had wheel wells that
> weren't quite tall enough.
>
> As far as the airbags raising and/or leveling, there are lots of things to
> check. Some have mentioned that people put shut-off valves at the bag.
> Check and see if it has them, and if they are in the OFF position.
>
> Then see if the compressor runs. Do that by turning the key to the "Run"
> position and listen for the compressor. If it doesn't run, check to see if
> it
> has been removed, then check the circuit breaker for the compressor. The
> circuit breaker is on the fuse block behind the glove compartment.
>
> If the compressor runs, see if it builds up pressure. If not, there might
> be a massive leak somewhere, or you might need a new compressor.
>
> Report back here after you get that far. Generally, if the compressor
> runs, and makes a little pressure, and there are no shut off valves in the
> line,
> it will either hiss at a leak, or raise the bags at least a little.
>
> Most important, read this:
>
> http://www.gmceast.com/technical/Denney_Power_Level_System.pdf
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Gene Fisher -- 74-23,77PB/ore/ca
“Give a man a fish; you have fed him for today --- give him a URL and
-------
http://bdub.net/gmcmotorhome.info/
Alternator Protection Cable
http://bdub.net/gmcmotorhome.info/APC.html

 

[Matt Colie]

Nathan,

Your coach is a 73-23, so it will probably cross a scale at less than 9700 This makes the weight of the fuel and water more of a factor than it is
in the later longer and heavier coaches. (Many Royales top 12000.)

I know this because I one had the coach ride height set with the water and fuel low.
First I put on 30 gallons of water (~250#) and shortly later took on 48 gallons of gasoline (~290#) and the coach's handling got squirrely. Some will
tell you it makes no difference. 500# in the ass end does make a difference, and the coach can handle it if it is given a chance.

Then I set the knobs to travel and things got better.

Matt
--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Still Loving OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit

 

[Rdenney]

Matt, that's exactly the reason for automatic ride height on GMC's.

It's also the reason I moved my water tank to a centered position under the
bed when I replaced the Adobe Posterior. Trying to correct for a diagonal
balance mismatch is harder than just tracking changes in rear load.

The factory Power Level system is simple and straightforward, easy to
troubleshoot, and generally bulletproof once the leaks are managed. It has
little of the complexity of the later systems. I could see replacing an
Electro Level II system that has bad pumps and electric air valves with a
wireless system, but it just isn't that hard to make a Power Level system
work well.

Rick "thinking if GM had original used valves of the quality JR Slaten
uses, they'd have never needed to 'upgrade' the air system" Denney

> Nathan,
>
> Your coach is a 73-23, so it will probably cross a scale at less than
> 9700 This makes the weight of the fuel and water more of a factor than
> it is
> in the later longer and heavier coaches. (Many Royales top 12000.)
>
> I know this because I one had the coach ride height set with the water and
> fuel low.
> First I put on 30 gallons of water (~250#) and shortly later took on 48
> gallons of gasoline (~290#) and the coach's handling got squirrely. Some
> will
> tell you it makes no difference. 500# in the ass end does make a
> difference, and the coach can handle it if it is given a chance.
>
> Then I set the knobs to travel and things got better.
>
> Matt
> --
> Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
> Still Loving OE Rear Drum Brakes with Applied Control Arms
> SE Michigan - Twixt A2 and Detroit
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Rick Denney
73 x-Glacier 230 "Jaws"
Off-list email to rick at rickdenney dot com

 

[robert mueller]

Rich, Matt,

I agree with both of you!

If the GMC suspension engineers didn't think the automatic leveling system
was necessary why did they install it?

AND why did the accountants approve it?

Regards,
Rob M.
The Pedantic Mechanic
USAussie - Downunder
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
USA '77 Kingsley - TZE 267V100808


-----Original Message-----
From: Gmclist [mailto:gmclist-bounces] On Behalf Of Richard
Denney
Sent: Monday, June 19, 2017 12:07 PM
To: gmclist
Subject: Re: [GMCnet] Air suspension and leveling system

Matt, that's exactly the reason for automatic ride height on GMC's.

It's also the reason I moved my water tank to a centered position under the
bed when I replaced the Adobe Posterior. Trying to correct for a diagonal
balance mismatch is harder than just tracking changes in rear load.

The factory Power Level system is simple and straightforward, easy to
troubleshoot, and generally bulletproof once the leaks are managed. It has
little of the complexity of the later systems. I could see replacing an
Electro Level II system that has bad pumps and electric air valves with a
wireless system, but it just isn't that hard to make a Power Level system
work well.

Rick "thinking if GM had original used valves of the quality JR Slaten
uses, they'd have never needed to 'upgrade' the air system" Denney

> Nathan,
>
> Your coach is a 73-23, so it will probably cross a scale at less than
> 9700 This makes the weight of the fuel and water more of a factor than
> it is
> in the later longer and heavier coaches. (Many Royales top 12000.)
>
> I know this because I one had the coach ride height set with the water and
> fuel low.
> First I put on 30 gallons of water (~250#) and shortly later took on 48
> gallons of gasoline (~290#) and the coach's handling got squirrely. Some
> will
> tell you it makes no difference. 500# in the ass end does make a
> difference, and the coach can handle it if it is given a chance.
>
> Then I set the knobs to travel and things got better.
>
> Matt
> --
> Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
> Still Loving OE Rear Drum Brakes with Applied Control Arms
> SE Michigan - Twixt A2 and Detroit
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Rick Denney
73 x-Glacier 230 "Jaws"
Off-list email to rick at rickdenney dot com
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

 

[jerry work]

Rich, Matt,

I agree with both of you!

If the GMC suspension engineers didn't think the automatic leveling system
was necessary why did they install it?

AND why did the accountants approve it?

Regards,
Rob M.
The Pedantic Mechanic
USAussie - Downunder
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
USA '77 Kingsley - TZE 267V100808

 

[Jim Hupy]

Let's see, they could have coil over airbags filled with a slurry of
magnetically sensitive material that could be surrounded by a strong
electromagnetic coil, the field strength of which could be influenced by
forward looking sensors. That way when a pothole or truck groove were
detected, the suspension could react before obstacles were encountered.
Many times a second.
Jim Hupy
Salem, Or
78 GMC ROYALE 403

> Hi Rob,
>
> Tongue firmly planted in cheek I would suggest your logic ignores the
> obvious.
>
> The GMC engineers did what they did based on technology available to them
> at the time. At that time they had no option for a far simpler, more
> reliable, less expensive and flexible Air control system such as we do
> today with things like the wireless air controller. Who knows how they
> might have elected to design this system if they did, but I really doubt
> they would have elected to fill the coach with air lines, fittings and
> numerous leak points as they had to do given the options available to them
> at the time. They likely also would not have had to try three times in six
> years to come up with the semi-satisfactory compromise.
>
> Tongue still firmly planted in cheek, if they had the same redesign rate
> over the ensuing 40 plus years if GMC continued to be produced we could now
> be dealing with auto air control system version 23. Hmmmmmm.
>
> Me thinks this is one case where newer technology trumps old school.
>
> Jerry
> Jerry Work
> The Dovetail Joint
> Fine furniture designed & hand crafted
> in the 1907 former Masonic Temple building
> in historic Kerby, OR
> http://jerrywork.com
> ................
> Message: 13
> Date: Mon, 19 Jun 2017 14:15:21 +1000
> From: "Rob Mueller"
> To:
> Subject: Re: [GMCnet] Air suspension and leveling system
> Message-ID:
> Content-Type: text/plain; charset="us-ascii"
>
> Rich, Matt,
>
> I agree with both of you!
>
> If the GMC suspension engineers didn't think the automatic leveling system
> was necessary why did they install it?
>
> AND why did the accountants approve it?
>
> Regards,
> Rob M.
> The Pedantic Mechanic
> USAussie - Downunder
> AUS '75 Avion - The Blue Streak TZE365V100428
> USA '75 Avion - Double Trouble TZE365V100426
> USA '77 Kingsley - TZE 267V100808
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

 

[johnny]

That sounds nice - and if it leveled en route, it would in fact be a more modern version of the OEM setups. As a 'set and it stays there' system, it
trumps a shutoff valve only in that you don't have to find a gas station and walk around back to set the height statically. Surely the inventor is in
the process of doing this.

--johnny
--
76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
"I forgive them all, save those who hurt the dogs. They must answer to me in hell" - ol Andy, paraphrased

 

[LQQKatJon]

Welcome. I will add my two cents.

1st, like Ken said, check for the shut off valves. If they do not have them, install them, it will make troubleshooting easier and give you time
to diagnose all the air system problems you have now and may have in the future. With the shut/off isolators you can pump up the bags with a working
or semi working system and not have to drive at 10mph with bumper dragging.

You can chase the valves/ fittings. Or buy from vender(much easier).

Scroll down past his air bags:
http://www.gmcmotorhomemarketplace.com/sully/

And or
http://www.appliedgmc.com/prod.itml/icOid/690

Then and for faye as well, you need to know if the compressor runs and can produce pressure. It takes 90+ pounds in oem airbags and i have seen two
cases this spring the original compressor was weak and could not pump well enough to shut off the pressure switch. (At like 120-130 psi). I have a
cheap air guage T ed onto my air tank. Then if it is getting enough pressure, and pump is still on, the pressure switch is common, and you can
then start hunting down leaks.

On a coach that has been sitting, I personally would install the airbag valves/isolators/schrader valves. Pump up airbags to a level height that is
1.5 inches lower in back then front. And drive the coach. Fix the obviius, but there might be more items that need attention then spending alot of
time figuring out if you have air leaks, leveling valves bad, and dash valves bad. Or having to spend a couple hundred on a new compressor. Get
your list together and figure out what is most important to address next. Make it stop, make it go. And then make it comfortable.

Get out and enjoy the coach.

--
Jon Roche
75 palm beach
St. Cloud, MN
http://lqqkatjon.blogspot.com/