How do I get some lift in the rear?

[mike]

Happy Easter to All,

I purchased my coach, 1975 Coahmen Royale last October and drove it to my shop to prepare for a interior renovation. It was suggested here that if
possible I should get pressure off the air bags while indoors for the project, so I jacked it up and placed jack-stands to get all tires off the
ground.

A few days ago I raised the coach and removed the jack stands, a short time later, maybe 20-30 minutes, I noticed the rear end lower than level by
about 2.5". I have a power level II system, I think? I have attached a couple of photo links for your review.

http://www.gmcmhphotos.com/photos/my-75-royale/p62734-image345.html
http://www.gmcmhphotos.com/photos/my-75-royale/p62736-image347.html
http://www.gmcmhphotos.com/photos/my-75-royale/p62735-image346.html
http://www.gmcmhphotos.com/photos/my-75-royale/p62733-image344.html

Once I get the coach running, how do I get it level again?

Thanks again for your help,
Mike

 

[Ken B]

With the coach running, set the power level switches to travel and wait. The leveling sense switches (which are air) located in the wheel wells
should take over and after some delay call for air to raise both bags of the coach to their correct levels.

To manually raise one bag without the other turn the appropriate switch to raise. This bypasses the leveling sense switches and simply puts air the
the appropriate bag. You must turn the switch back again to hold when you reach your desired height.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana

 

[RonaldPottol]

Do note that it should look lower at the rear, yes, it looks odd, but it's
normal, and will handle better.

> Happy Easter to All,
>
> I purchased my coach, 1975 Coahmen Royale last October and drove it to my
> shop to prepare for a interior renovation. It was suggested here that if
> possible I should get pressure off the air bags while indoors for the
> project, so I jacked it up and placed jack-stands to get all tires off the
> ground.
>
> A few days ago I raised the coach and removed the jack stands, a short
> time later, maybe 20-30 minutes, I noticed the rear end lower than level by
> about 2.5". I have a power level II system, I think? I have attached a
> couple of photo links for your review.
>
> http://www.gmcmhphotos.com/photos/my-75-royale/p62734-image345.html
> http://www.gmcmhphotos.com/photos/my-75-royale/p62736-image347.html
> http://www.gmcmhphotos.com/photos/my-75-royale/p62735-image346.html
> http://www.gmcmhphotos.com/photos/my-75-royale/p62733-image344.html
>
> Once I get the coach running, how do I get it level again?
>
> Thanks again for your help,
> Mike
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

 

[Ken H.]

Mike,

You do have the PowerLevel system and, fortunately, you've already got JR
Slaten's control valves so you should never have a problem in that area of
the system. When you blocked the coach with the weight off the wheels, the
system attempted to level automatically, causing it to be low when you put
it back on the ground. As Ken B. suggested, all should be well if you just
wait.

You should probably check the manual for how to set ride height. After you
set it to the correct height using the tops of the slots in the right frame
rail, measure from the ground to the BOTTOM of the frame front and rear.
Then cut a measuring stick to those heights (I prefer a stepped 1x4, 2x4 or
4x4). That can be used on the left rear, where the Onan obstructs the
slot. It will be quick and easy to use that stick in the future -- mark
the steps for front and rear to help your memory as it ages.

Ken H.

 

[mike]

You guys are the best, thanks for your responses.
Mike

 

[Matt Colie]

> You guys are the best, thanks for your responses.
> Mike

Mike,

Just to be clear (why we hope people will fill in the sigfile), a '75 Coachman Royale should have an Electro-Level(I) system. You have three rocker
switches in the front and someplace in the back is a pump, a tank and collection of little solenoid valves.

Electro-Level II have the same switches, but two air pumps and the height control is an electronic part.

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

 

[Ken H.]

Matt,

I'm afraid we're about to confuse Mike. He DEFINITELY has Power Level II
-- JR's rotary valves, as shown in the first photo he posted. And his
compressor is a Firestone, mounted up front, as shown in his 3rd photo.

I suspect his coach did come from the factory with Power Level, but even if
it originally had Electrolevel, that's all gone now and he has PL II.

Ken H.

> > You guys are the best, thanks for your responses.
> > Mike
>
> Mike,
>
> Just to be clear (why we hope people will fill in the sigfile), a '75
> Coachman Royale should have an Electro-Level(I) system. You have three
> rocker
> switches in the front and someplace in the back is a pump, a tank and
> collection of little solenoid valves.
>
> Electro-Level II have the same switches, but two air pumps and the height
> control is an electronic part.
>

 

[thomas phipps]

And, while you are chasing along the air suspension, check for schrader valves and shut off valves added to each air bag. Gives you a rapid repair
option if the air system fails. Blow the bags up and git her home.
Tom, MS II
--
1975 GMC Avion
KA4CSG

 

[Ken H.]

Tom,

Mike's 4th photo shows that he does have cutoff and Schrader valves. IMHO,
their positions should be reversed, but that could be argued.

Incidentally, he also has adjustable ride height links. Someone has been
through the entire suspension control system.

Ken H.

> And, while you are chasing along the air suspension, check for schrader
> valves and shut off valves added to each air bag. Gives you a rapid repair
> option if the air system fails. Blow the bags up and git her home.
> Tom, MS II
> --
>

 

[don adams]

Yes and in the last photo, the valve is closed so it is not going to raise.
--
Don Adams Dallas, TX
'76 26' Glenbrook, '90 Sidekick
rebuilt by R Archer, powered by J Bounds, Koba

"]http://www.gmcmhphotos.com/photos/data/6109/G2.jpg[/IMG][/url]

 

[mike]

Ken H. Thanks for helping to clarify, I was about to ask regarding the Power Level II being changed by a PO. So to confirm the system I have is a
Power Level II system, is there anything else I need to know about it, safety or maintenance or other?

Now I need to ask about the Schrader valve position (light pink looking valve in 4th photo), once I start the coach and prior to placing the power
level switch to travel, should I "open" the valve, go through the sequence until the coach raises at the rear and levels out then place the switch in
the hold position and turn the Schrader valve back to the current position (closed)?

Thanks again for the continued support,
Regards,
Mike

 

[kerry pinkerton]

The Schrader valve is the tire stem thing above the shut off by the bag. It's purpose is to allow you to air up the bag with an external compressor
or air tank in the event of a pump or system failure.

The shut off valve (closest to your bag) is intended to isolate your bag and prevent it from leaking down. If it's closed, the bag will never
inflate.

http://www.gmcmhphotos.com/photos/my-75-royale/p62733-image344.html

> Tom,
>
> Mike's 4th photo shows that he does have cutoff and Schrader valves. IMHO,
> their positions should be reversed, but that could be argued....

I agree with Ken Henderson on the placement of the shut off and Schrader valve. I'd think you'd want the Schrader valve closest to the bag. In your
current situation, if you have a blown line or other open condition any air you tried to put into the Schrader valve would just blow out and never get
into the bag. If the shut off with on the other side of the Schrader valve, you could manually close the shutoff valve and air up (or down) the bag
using the Schrader valve.
--
Kerry Pinkerton - North Alabama

77 Eleganza II, 403CI, Manny Brakes, 1 ton, tranny, lots of aluminum goodies.

http://www.bdub.net/pinkerton/

'03 Fleetwood Discovery 39L

 

[Ken H.]

What Kerry said.

And to answer your procedural question: No, if the rest of your system
(dash valves, hoses, fittings) is air-tight, as I'd expect from the
upgrades we see, you should always leave the shutoff valves at the air bags
open. That way, the system can operate normally to maintain the correct
ride height. You should only need the at-bag valves in an "emergency".

If you do have air leaks, they're probably at a hose fitting and readily
detectable by bubble soap. It's unlikely that JR Slaten's "Power Level II"
valves themselves are leaking, considering their industrial quality.

HTH,

Ken H.

On Mon, Apr 17, 2017 at 8:44 AM, Kerry Pinkerton
wrote:

> The Schrader valve is the tire stem thing above the shut off by the bag.
> It's purpose is to allow you to air up the bag with an external compressor
> or air tank in the event of a pump or system failure.
>
> The shut off valve (closest to your bag) is intended to isolate your bag
> and prevent it from leaking down. If it's closed, the bag will never
> inflate.
>
> http://www.gmcmhphotos.com/photos/my-75-royale/p62733-image344.html
>
>

> > Tom,
> >
> > Mike's 4th photo shows that he does have cutoff and Schrader valves.
> IMHO,
> > their positions should be reversed, but that could be argued....
>
>
> I agree with Ken Henderson on the placement of the shut off and Schrader
> valve. I'd think you'd want the Schrader valve closest to the bag. In your
> current situation, if you have a blown line or other open condition any
> air you tried to put into the Schrader valve would just blow out and never
> get
> into the bag. If the shut off with on the other side of the Schrader
> valve, you could manually close the shutoff valve and air up (or down) the
> bag
> using the Schrader valve.
> --
> Kerry Pinkerton - North Alabama
>
> 77 Eleganza II, 403CI, Manny Brakes, 1 ton, tranny, lots of aluminum
> goodies.
>
> http://www.bdub.net/pinkerton/
>
> '03 Fleetwood Discovery 39L
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

 

[robert mueller]

Mike,

Here's a link to a document that covers the Powerlevel system from soup to
nuts!

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

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 Mike
Sent: Monday, April 17, 2017 7:00 AM
To: gmclist
Subject: Re: [GMCnet] How do I get some lift in the rear?

Ken H. Thanks for helping to clarify, I was about to ask regarding the Power
Level II being changed by a PO. So to confirm the system I have is a
Power Level II system, is there anything else I need to know about it,
safety or maintenance or other?

Now I need to ask about the Schrader valve position (light pink looking
valve in 4th photo), once I start the coach and prior to placing the power
level switch to travel, should I "open" the valve, go through the sequence
until the coach raises at the rear and levels out then place the switch in
the hold position and turn the Schrader valve back to the current position
(closed)?

Thanks again for the continued support,
Regards,
Mike

_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

 

[mark kasiewicz]

What all can we expect from a old gall from the 70's ? Just be glad she
takes the bumps pretty well and keeps her tail in line !

Mark Kasiewicz (on Behalf of Dawn Koepp)
Gus da Bus
'77 Kingsley (in renovation.... gotta get those toll windows to stop
leaking !)
Eau Claire, WI

 

[mike]

Kerry, Ken H. And Rob, thank you for your response's. I believe I now have a better understanding of the system.

I will read the document that covers the PowerLevel system, what a learning curve and thanks again to everyone that contributes to help the community
as a whole.

Stay Well,
Mike

 

[Gene Fisher]

Read here
http://www.gmcmhphotos.com/photos/airbag-cutoff-valve/p1835.html

> Kerry, Ken H. And Rob, thank you for your response's. I believe I now have
> a better understanding of the system.
>
> I will read the document that covers the PowerLevel system, what a
> learning curve and thanks again to everyone that contributes to help the
> community
> as a whole.
>
> Stay Well,
> Mike
>
> _______________________________________________
> 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

 

[mike]

Thanks Gene, BTW I received the APC, another "to-do" item added to the list.
Mike

 

[thomas phipps]

Mike, leave the cut-off valve in the open position for the air system to work as designed. The valves are used to isolate the air bag from the rest of
the system in case of a problem. When you have your system working, and the coach is at the correct ride height, take an air pressure gauge and
measure the air pressure in the bag. This would be your goal, if you have to isolate the air bag from the rest of the air system for any reason.
You can close the valve and drive the coach, if you wish. This is the same result as placing the power level knob in the 'hold' position.
Tom, MS II
--
1975 GMC Avion
KA4CSG

 

[johnny]

In addition to movving the schrader valve to the bag side of the cutoff valve, run the bags all the way down and check to see that the positioning
valve arm doesn't hit the air line looped over behind it. Ask me how I know this can be a problem

--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