Air bag/Piping Leak

[LQQKatJon]

OEM air bags run between 90-105 psi. You can pump a bit more air into them.

Check if you have any plastic fittings, and go to a good truck part supply place and replace them with good brass DOT one's.

Leak down overnight, I think you will find easily. Leaking down after a few days, I think you may be better installing shut off valves right at the
Bags, and save your time trying to hunt down that leak. Especially on your newer Royale that I don't think has much air capacity, and you need to
find that leak with the pump running full tilt.

My coach drops in a bout a weeks time, not fully, but noticeably. When I leave it parked, I just flip the valve closed on the bags and it stays
level. When I go to leave, I flip the valve open and the air system is operational. Also forces me to do a walk around the coach once in a while
to look for other oddities. I could not find my leak.

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

 

[Matt Colie]

> I've got a '78 Royale (owned about six months) and have had an air leak for the past couple of weeks. Start up and bags air up but the right side
> leaks down over a period of several days. I've checked for audible leaks (no luck, but with my poor hearing, it was a long shot at best).
>
> I'm going the "soapy water" route and would like to know the maximum pressure allowed on the bags. Any help is much appreciated.
>
> P. S. As an aside, what's the normal operating pressure when travelling down the road. Thanks again....

John,

You have been here since April, but never officially welcomed.

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

Leaks of the airbag itself are rare, but do happen. Along that line, be vary careful when you are around the airbags (airsprings) as they are known
to burst with no warning at all. This is also why you always block the coach when you go under it. If you are wondering, if you have a 2X4 under the
coach and dump the air, you will not be able to get the board out.

Please do both us and you a favor, go to and scroll down to where you can put in a sigfile. This should have your
real name (so others will know you when you meet), a short bit about the coach (year, model and major mods)because there can be big differences and a
geographic reference (because the e-mail readers don't get the header) because someone in striking distance may want to offer assistance. Then
remember to scroll down more to .

If you don't have the valve and schrader set on the rear springs, order up a pair of 1/4 pipe-schrader adapters to carry in the case that the air
system takes a hit. You should also consider carrying a little 12V compressor.

If you have not figured it out already, you are now a part of an amazing community. It is full of helpful and supporting people that want you to
enjoy your coach as much as we all enjoy both our coaches and the community. I have a special way of welcoming new people (that I missed in April)
because the only other community that I know of that is this solid is that of the watermen that are my world. I like to welcome a new owner here much
as a new owner or vessel is welcomed there. So,

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

Welcome John

Matt
--
Matt & Mary Colie - Members GMCMI, GMCGL, GMCES
'73 Glacier 23 - Still Loving OE Rear Drum Brake with Applied Control Arms
Now with both true Keyless and remote entry
SE Michigan - Twixt A2 and Detroit

 

[Jim Hupy]

John, go to the dollar store and buy a bottle of child's bubble soap. Super
concentrated and thick enough that it won't soon run off the fittings. Open
the bed on the rear drivers side of the coach to expose the EL 2 air bag
system. Drizzle soap solution onto the top of the compressors, the
dessicant/driers, the air line connectors and the solenoid air connections.
Then, go to the wheel wells and soap all the air line connections that you
find, including where they enter the bags. (Likely leak source). Turn the
ignition onto accessory, and see if you hear the compressors run. Wait a
few minutes, then inspect where you have applied the soap. You should have
a bubbly mess where your leak (s) is located. Don't be suprised to find
more than one. Fix as required.
Jim Hupy
Salem, Or
78 GMC ROYALE 403

> > I've got a '78 Royale (owned about six months) and have had an air leak
> for the past couple of weeks. Start up and bags air up but the right side
> > leaks down over a period of several days. I've checked for audible
> leaks (no luck, but with my poor hearing, it was a long shot at best).
> >
> > I'm going the "soapy water" route and would like to know the maximum
> pressure allowed on the bags. Any help is much appreciated.
> >
> > P. S. As an aside, what's the normal operating pressure when travelling
> down the road. Thanks again....
>
> John,
>
> You have been here since April, but never officially welcomed.
>
> Welcome to the group, family, cult, asylum....
>
> Leaks of the airbag itself are rare, but do happen. Along that line, be
> vary careful when you are around the airbags (airsprings) as they are known
> to burst with no warning at all. This is also why you always block the
> coach when you go under it. If you are wondering, if you have a 2X4 under
> the
> coach and dump the air, you will not be able to get the board out.
>
> Please do both us and you a favor, go to
> and scroll down to where you can put in a sigfile. This should have your
> real name (so others will know you when you meet), a short bit about the
> coach (year, model and major mods)because there can be big differences and a
> geographic reference (because the e-mail readers don't get the header)
> because someone in striking distance may want to offer assistance. Then
> remember to scroll down more to .
>
> If you don't have the valve and schrader set on the rear springs, order up
> a pair of 1/4 pipe-schrader adapters to carry in the case that the air
> system takes a hit. You should also consider carrying a little 12V
> compressor.
>
> If you have not figured it out already, you are now a part of an amazing
> community. It is full of helpful and supporting people that want you to
> enjoy your coach as much as we all enjoy both our coaches and the
> community. I have a special way of welcoming new people (that I missed in
> April)
> because the only other community that I know of that is this solid is that
> of the watermen that are my world. I like to welcome a new owner here much
> as a new owner or vessel is welcomed there. So,
>
> May the Good Lord Bless this coach and all those that set forth within her.
>
> Welcome John
>
> Matt
> --
> Matt & Mary Colie - Members GMCMI, GMCGL, GMCES
> '73 Glacier 23 - Still Loving OE Rear Drum Brake with Applied Control Arms
> Now with both true Keyless and remote entry
> SE Michigan - Twixt A2 and Detroit
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

 

[paul zerkel]

SCFire,

You have a 78 so it is most likely an Electrolevel II system. They are a little different than the Power Level (which is what most 73-76) coaches have
(and makes up the majority here); Some 77's had an ElectroLevel I which was an intermediate system that I do not know a lot about.

The ElectroLevel II on the '78s does not have an air tank. But it has two compressors (one for each side). You can force the compressor(s) to run
though, by putting your middle switch in "hold" and then putting either or both switches in "raise". This would put enough pressure in the lines, that
I would think you could do a bubble test.

I have a 1978 Eleganza, and the location of my compressors is in the passenger side cabinet under where the power converter is installed, but it is
likely in a different location on your Royale. Maybe someone with a 78 Royale will chime in. They aren't hard to find though; put one in raise and
then walk around the coach listening for compressor noise

The Electrolevel II's have less tubing overall, but two compressors vs one, and some finicky electronic components. If your ride height sensors are
working, count yourself among the lucky ones.

--
Paul Zerkel
'78 Eleganza II
Salisbury IL (near Springfield)

 

[charles boyd]

Bags can leak down from other places. Usually there is a clump of oem inline connectors around the brake booster. Spray with soapy water and observe
as helper changes valves. In travel leave it 30 sec or so to open. Check each connection. Inside the panel the connectors or valves themselves
could leak. Again check each in every position. I use The DOT brass inline slip on connectors for replacement. Push on real hard to seat.
Operating pressure varies with load weight versus preset ride height. It varies but as long as ride height is adjusted correctly it's ok. Coach air
systems are set ~ 125psi max. Most big trucks are regulated to 90psi out of the 125 psi in the tank. The air bags should take a whole lot more just
from pot holes. I'm thinking 500 or better.

> I've got a '78 Royale (owned about six months) and have had an air leak for the past couple of weeks. Start up and bags air up but the right side
> leaks down over a period of several days. I've checked for audible leaks (no luck, but with my poor hearing, it was a long shot at best).
>
> I'm going the "soapy water" route and would like to know the maximum pressure allowed on the bags. Any help is much appreciated.
>
> P. S. As an aside, what's the normal operating pressure when travelling down the road. Thanks again....

--
C. Boyd
76 Crestmont
East Tennessee

 

[jim kanomata1]

Should you not detect a leak outside the system, then check the solenoid
valves as there is always a chance that a particulate might be on the valve
face causing a poor seal.

> SCFire,
>
> You have a 78 so it is most likely an Electrolevel II system. They are a
> little different than the Power Level (which is what most 73-76) coaches
> have
> (and makes up the majority here); Some 77's had an ElectroLevel I which
> was an intermediate system that I do not know a lot about.
>
> The ElectroLevel II on the '78s does not have an air tank. But it has two
> compressors (one for each side). You can force the compressor(s) to run
> though, by putting your middle switch in "hold" and then putting either or
> both switches in "raise". This would put enough pressure in the lines, that
> I would think you could do a bubble test.
>
> I have a 1978 Eleganza, and the location of my compressors is in the
> passenger side cabinet under where the power converter is installed, but it
> is
> likely in a different location on your Royale. Maybe someone with a 78
> Royale will chime in. They aren't hard to find though; put one in raise and
> then walk around the coach listening for compressor noise
>
> The Electrolevel II's have less tubing overall, but two compressors vs
> one, and some finicky electronic components. If your ride height sensors are
> working, count yourself among the lucky ones.
>
>
>
> --
> Paul Zerkel
> '78 Eleganza II
> Salisbury IL (near Springfield)
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

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

 

[Ken B]

You can also find 1/4" schrader valves at Ace hardware. I believe they are around $2.00 each. I have a pair somewhere in the coach but have never
used them.

When I had air leaks that I could not easily find, I replaced ALL of the plastic air line fittings. I found the replacements locally at an
independent Auto Parts store. NAPA also also has them at twice the price. Now my system sits all winter without going down.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana

 

[john sharpe]

John, Do you have Electro Level II? If you have a unit with 2 small compressors inside the coach near the left rear tire and electric level sensors
in the wheelwells (no air hoses connected to the sensors), then it's Electro-Level II. In that case, with age the hold valves begin to leak causing
the problem you describe.

One way to check the hold valves is to install a block off valve on the air bag. Pump the bag up to ride height and close the block off valve and use
the panel switch to energize the down button for 20 seconds. If the bag stays up after a few days, you can surmise that the bag and lines to the
block off valve are not leaking. Now the problem is the line to the hold valve solenoid or the hold valve solenoid itself. To check the hold valve,
you need to: 1) disconnect the line from the compressor to the hold valve solenoid. 2) open the block off valve at the inflated air bag. 3) Use soap
bubbles on the inlet of the hold valve solenoid to see if it's leaking. If it's not, you need to repeat the test because it's either the line or the
hold valve solenoid.
--
John Sharpe
Porter, TX
78 Eleganza II, TBI
40 Ford Panel, TPI

 

[Jim Hupy]

John, in addition to what you described, the top of the cylinder heads of
the compressors needs to be soap tested as well. There is a Schrader cap on
the top of the heads. They can and frequently do leak air, whether the
compressors are running or not. They are often overlooked.
Jim Hupy
Salem, Or (Presently at a GMC CASCADES RALLY IN FERNDALE, WA. )
78 GMC ROYALE 403

> John, Do you have Electro Level II? If you have a unit with 2 small
> compressors inside the coach near the left rear tire and electric level
> sensors
> in the wheelwells (no air hoses connected to the sensors), then it's
> Electro-Level II. In that case, with age the hold valves begin to leak
> causing
> the problem you describe.
>
> One way to check the hold valves is to install a block off valve on the
> air bag. Pump the bag up to ride height and close the block off valve and
> use
> the panel switch to energize the down button for 20 seconds. If the bag
> stays up after a few days, you can surmise that the bag and lines to the
> block off valve are not leaking. Now the problem is the line to the hold
> valve solenoid or the hold valve solenoid itself. To check the hold valve,
> you need to: 1) disconnect the line from the compressor to the hold valve
> solenoid. 2) open the block off valve at the inflated air bag. 3) Use soap
> bubbles on the inlet of the hold valve solenoid to see if it's leaking. If
> it's not, you need to repeat the test because it's either the line or the
> hold valve solenoid.
> --
> John Sharpe
> Porter, TX
> 78 Eleganza II, TBI
> 40 Ford Panel, TPI
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

 

[Jim Hupy]

Darn spell correct!. That should read GMC Cascaders Rally. Ferndale is only
a few miles from the Canadian Border. It is Dec. 3, and we are still using
our coaches. Next rally is Valentine's Day early February. Such is GMC'n in
the Pacific Northwest. Use 'em year round.
Jim Hupy

> John, in addition to what you described, the top of the cylinder heads of
> the compressors needs to be soap tested as well. There is a Schrader cap on
> the top of the heads. They can and frequently do leak air, whether the
> compressors are running or not. They are often overlooked.
> Jim Hupy
> Salem, Or (Presently at a GMC CASCADES RALLY IN FERNDALE, WA. )
> 78 GMC ROYALE 403
>

>
>> John, Do you have Electro Level II? If you have a unit with 2 small
>> compressors inside the coach near the left rear tire and electric level
>> sensors
>> in the wheelwells (no air hoses connected to the sensors), then it's
>> Electro-Level II. In that case, with age the hold valves begin to leak
>> causing
>> the problem you describe.
>>
>> One way to check the hold valves is to install a block off valve on the
>> air bag. Pump the bag up to ride height and close the block off valve and
>> use
>> the panel switch to energize the down button for 20 seconds. If the bag
>> stays up after a few days, you can surmise that the bag and lines to the
>> block off valve are not leaking. Now the problem is the line to the hold
>> valve solenoid or the hold valve solenoid itself. To check the hold valve,
>> you need to: 1) disconnect the line from the compressor to the hold valve
>> solenoid. 2) open the block off valve at the inflated air bag. 3) Use soap
>> bubbles on the inlet of the hold valve solenoid to see if it's leaking.
>> If it's not, you need to repeat the test because it's either the line or the
>> hold valve solenoid.
>> --
>> John Sharpe
>> Porter, TX
>> 78 Eleganza II, TBI
>> 40 Ford Panel, TPI
>>
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
>