Rear air suspension question....things just arent adding up.

[6cuda6]

So been working on the rear air suspension of my Electro Level 1 system because i accidently dropped the right side (well i just tried the
switch....it dumped the whole bag in a split second) and it wont refill.

I replaced the DANA compressor with a known good one because mine was weak along with a faulty check valve and pressure gauge. Got it all back
together and still no lift....right side doesnt build pressure but the left side doesnt.

So i hit "travel mode" to see what would happen....i assumed the bags would balance left/right but nope....right side stayed the same and so did left
with no visible pressure increase on gauge.

All solinoids have power and click.....right side raise solenoid (one with blue line) works and allows air when i blow in it....lower solenoid (middle
of the three) allows air to flow when i blow in it....the last solinoid works(one with yellow line) but i cant verify air passage because i have
remove a bunch of other stuff in the way.....

So heres my thought on this.....one would suspect the bag or line to the bag as having a leak because the gauge never builds pressure (right side or
travel mode) but there is zero audible air leakage....which would leave me, you would think with a plugged solinoid but that would build pressure,
which it doesnt.

The other question i have is how much air should be coming out of the system at the solinoids? I would think enough that if you plugged the hole with
your thumb you'd feel it.....no?

--
Rich Mondor,

Brockville, ON

77 Hughes 2600

 

[jim kanomata1]

Build up air on the good side,keep the middle switch on Hold,
Then immediately put Raise on weak side as now you have pressure in tank
that will dump to the weak side

On Mon, Jul 29, 2019 at 7:22 PM tonka6cuda6--- via Gmclist <

> So been working on the rear air suspension of my Electro Level 1 system
> because i accidently dropped the right side (well i just tried the
> switch....it dumped the whole bag in a split second) and it wont refill.
>
> I replaced the DANA compressor with a known good one because mine was weak
> along with a faulty check valve and pressure gauge. Got it all back
> together and still no lift....right side doesnt build pressure but the
> left side doesnt.
>
> So i hit "travel mode" to see what would happen....i assumed the bags
> would balance left/right but nope....right side stayed the same and so did
> left
> with no visible pressure increase on gauge.
>
>
> All solinoids have power and click.....right side raise solenoid (one with
> blue line) works and allows air when i blow in it....lower solenoid (middle
> of the three) allows air to flow when i blow in it....the last solinoid
> works(one with yellow line) but i cant verify air passage because i have
> remove a bunch of other stuff in the way.....
>
> So heres my thought on this.....one would suspect the bag or line to the
> bag as having a leak because the gauge never builds pressure (right side or
> travel mode) but there is zero audible air leakage....which would leave
> me, you would think with a plugged solinoid but that would build pressure,
> which it doesnt.
>
> The other question i have is how much air should be coming out of the
> system at the solinoids? I would think enough that if you plugged the hole
> with
> your thumb you'd feel it.....no?
>
>
> --
> Rich Mondor,
>
> Brockville, ON
>
> 77 Hughes 2600
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Jim Kanomata
Applied/GMC, Newark,CA
jimk
http://www.appliedgmc.com
1-800-752-7502

 

[Matt Colie]

> So been working on the rear air suspension of my Electro Level 1 system because i accidently dropped the right side (well i just tried the
> switch....it dumped the whole bag in a split second) and it wont refill.
>
> I replaced the DANA compressor with a known good one because mine was weak along with a faulty check valve and pressure gauge. Got it all back
> together and still no lift....right side doesnt build pressure but the left side doesnt.
>
> So i hit "travel mode" to see what would happen....i assumed the bags would balance left/right but nope....right side stayed the same and so did
> left with no visible pressure increase on gauge.
>
>
> All solinoids have power and click.....right side raise solenoid (one with blue line) works and allows air when i blow in it....lower solenoid
> (middle of the three) allows air to flow when i blow in it....the last solinoid works(one with yellow line) but i cant verify air passage because i
> have remove a bunch of other stuff in the way.....
>
> So heres my thought on this.....one would suspect the bag or line to the bag as having a leak because the gauge never builds pressure (right side
> or travel mode) but there is zero audible air leakage....which would leave me, you would think with a plugged solinoid but that would build
> pressure, which it doesnt.
>
> The other question i have is how much air should be coming out of the system at the solinoids? I would think enough that if you plugged the hole
> with your thumb you'd feel it.....no?

Rich,

Yes, if you disconnect the line that goes to an airspring(bag) and that side is switched to "Raise", then there should be significant pressure at that
port.
Or, if it is switched to "Travel" and that side is down, then the height control valve should be supplying about that same pressure.

Are these still the OE Airsprings (bags)??
One know issue with the Sully system is the air port of the spring can get blocked when the suspension is flat.

The system is controlled by the ride height control valves in each rear wheel well. Do not expect one side to react to the state of the other.

Matt
--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan
OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit

 

[Ken H.]

The blocking of the air inlet port on a flat Sully Bag had never come to my
attention until recently when we became involved with a stranded GMCer
nearby. My son "rescued" the coach and had to jack up the flat side to get
air into the bag.

Has anyone devised a way to correct the problem? Having never seen one
myself, it's a pure WAG when I guess that the simple act of grinding a
groove across the area where the bag rests when flat might provide a path
for the air to sneak past. Seems to me that, or a better solution should
always be applied before the bags are installed. Huh?

Ken H.

On Tue, Jul 30, 2019 at 9:34 AM Matt Colie via Gmclist <

> > So been working on the rear air suspension of my Electro Level 1 system
> because i accidently dropped the right side (well i just tried the
> > switch....it dumped the whole bag in a split second) and it wont refill.
> >
> > I replaced the DANA compressor with a known good one because mine was
> weak along with a faulty check valve and pressure gauge. Got it all back
> > together and still no lift....right side doesnt build pressure but the
> left side doesnt.
> >
> > So i hit "travel mode" to see what would happen....i assumed the bags
> would balance left/right but nope....right side stayed the same and so did
> > left with no visible pressure increase on gauge.
> >
> >
> > All solinoids have power and click.....right side raise solenoid (one
> with blue line) works and allows air when i blow in it....lower solenoid
> > (middle of the three) allows air to flow when i blow in it....the last
> solinoid works(one with yellow line) but i cant verify air passage because i
> > have remove a bunch of other stuff in the way.....
> >
> > So heres my thought on this.....one would suspect the bag or line to the
> bag as having a leak because the gauge never builds pressure (right side
> > or travel mode) but there is zero audible air leakage....which would
> leave me, you would think with a plugged solinoid but that would build
> > pressure, which it doesnt.
> >
> > The other question i have is how much air should be coming out of the
> system at the solinoids? I would think enough that if you plugged the hole
> > with your thumb you'd feel it.....no?
>
> Rich,
>
> Yes, if you disconnect the line that goes to an airspring(bag) and that
> side is switched to "Raise", then there should be significant pressure at
> that
> port.
> Or, if it is switched to "Travel" and that side is down, then the height
> control valve should be supplying about that same pressure.
>
> Are these still the OE Airsprings (bags)??
> One know issue with the Sully system is the air port of the spring can get
> blocked when the suspension is flat.
>
> The system is controlled by the ride height control valves in each rear
> wheel well. Do not expect one side to react to the state of the other.
>
> Matt
> --
> Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
> Electronically Controlled Quiet Engine Cooling Fan
> 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
>

 

[6cuda6]

> > So been working on the rear air suspension of my Electro Level 1 system because i accidently dropped the right side (well i just tried the
> > switch....it dumped the whole bag in a split second) and it wont refill.
> >
> > I replaced the DANA compressor with a known good one because mine was weak along with a faulty check valve and pressure gauge. Got it all back
> > together and still no lift....right side doesnt build pressure but the left side doesnt.
> >
> > So i hit "travel mode" to see what would happen....i assumed the bags would balance left/right but nope....right side stayed the same and so
> > did left with no visible pressure increase on gauge.
> >
> >
> > All solinoids have power and click.....right side raise solenoid (one with blue line) works and allows air when i blow in it....lower solenoid
> > (middle of the three) allows air to flow when i blow in it....the last solinoid works(one with yellow line) but i cant verify air passage because
> > i have remove a bunch of other stuff in the way.....
> >
> > So heres my thought on this.....one would suspect the bag or line to the bag as having a leak because the gauge never builds pressure (right
> > side or travel mode) but there is zero audible air leakage....which would leave me, you would think with a plugged solinoid but that would build
> > pressure, which it doesnt.
> >
> > The other question i have is how much air should be coming out of the system at the solinoids? I would think enough that if you plugged the
> > hole with your thumb you'd feel it.....no?
>
> Rich,
>
> Yes, if you disconnect the line that goes to an airspring(bag) and that side is switched to "Raise", then there should be significant pressure at
> that port.
> Or, if it is switched to "Travel" and that side is down, then the height control valve should be supplying about that same pressure.
>
> Are these still the OE Airsprings (bags)??
> One know issue with the Sully system is the air port of the spring can get blocked when the suspension is flat.
>
> The system is controlled by the ride height control valves in each rear wheel well. Do not expect one side to react to the state of the other.
>
> Matt

OE style Firestones...which are weathered but appear to be holding air well enough to drive the coach back 700 miles from were we bought it.
--
Rich Mondor,

Brockville, ON

77 Hughes 2600

 

[6cuda6]

So i replaced another cracked fitting, which is neither here nor there at this point.

I reassembled everything and tried Jim's trick but not good enough so i got fed up and added a schrader valve to the pressure tank and went a grabbed
my portable compressor....aired up real nice....lol.

So i guess the ticket is going to be a new Viair compressor and no more DANA as it just doesnt seem to put out the volume necessary without really
working super hard and/or forever it seems.
--
Rich Mondor,

Brockville, ON

77 Hughes 2600

 

[6cuda6]

So next question....what size Viair? 350c or 450c? I want to put in in the stock location were the DANA went.
--
Rich Mondor,

Brockville, ON

77 Hughes 2600

 

[Jim Hupy]

Just disconnect the air line at the air bag. Unscrew the fitting that goes
into the air bag. Screw a Schrader valve into the air bag. Inflate to 90
psi. Drive it home. Fix it there.
Jim Hupy

On Tue, Jul 30, 2019, 12:04 PM tonka6cuda6--- via Gmclist <

> > > So been working on the rear air suspension of my Electro Level 1
> system because i accidently dropped the right side (well i just tried the
> > > switch....it dumped the whole bag in a split second) and it wont
> refill.
> > >
> > > I replaced the DANA compressor with a known good one because mine was
> weak along with a faulty check valve and pressure gauge. Got it all back
> > > together and still no lift....right side doesnt build pressure but the
> left side doesnt.
> > >
> > > So i hit "travel mode" to see what would happen....i assumed the bags
> would balance left/right but nope....right side stayed the same and so
> > > did left with no visible pressure increase on gauge.
> > >
> > >
> > > All solinoids have power and click.....right side raise solenoid (one
> with blue line) works and allows air when i blow in it....lower solenoid
> > > (middle of the three) allows air to flow when i blow in it....the last
> solinoid works(one with yellow line) but i cant verify air passage because
> > > i have remove a bunch of other stuff in the way.....
> > >
> > > So heres my thought on this.....one would suspect the bag or line to
> the bag as having a leak because the gauge never builds pressure (right
> > > side or travel mode) but there is zero audible air leakage....which
> would leave me, you would think with a plugged solinoid but that would build
> > > pressure, which it doesnt.
> > >
> > > The other question i have is how much air should be coming out of the
> system at the solinoids? I would think enough that if you plugged the
> > > hole with your thumb you'd feel it.....no?
> >
> > Rich,
> >
> > Yes, if you disconnect the line that goes to an airspring(bag) and that
> side is switched to "Raise", then there should be significant pressure at
> > that port.
> > Or, if it is switched to "Travel" and that side is down, then the height
> control valve should be supplying about that same pressure.
> >
> > Are these still the OE Airsprings (bags)??
> > One know issue with the Sully system is the air port of the spring can
> get blocked when the suspension is flat.
> >
> > The system is controlled by the ride height control valves in each rear
> wheel well. Do not expect one side to react to the state of the other.
> >
> > Matt
>
> OE style Firestones...which are weathered but appear to be holding air
> well enough to drive the coach back 700 miles from were we bought it.
> --
> Rich Mondor,
>
> Brockville, ON
>
> 77 Hughes 2600
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

 

[6cuda6]

> Just disconnect the air line at the air bag. Unscrew the fitting that goes
> into the air bag. Screw a Schrader valve into the air bag. Inflate to 90
> psi. Drive it home. Fix it there.
> Jim Hupy
>
> On Tue, Jul 30, 2019, 12:04 PM tonka6cuda6--- via Gmclist <

>

> >>> So been working on the rear air suspension of my Electro Level 1
> > system because i accidently dropped the right side (well i just tried the
> >>> switch....it dumped the whole bag in a split second) and it wont
> > refill.
> >>>
> >>> I replaced the DANA compressor with a known good one because mine was
> > weak along with a faulty check valve and pressure gauge. Got it all back
> >>> together and still no lift....right side doesnt build pressure but the
> > left side doesnt.
> >>>
> >>> So i hit "travel mode" to see what would happen....i assumed the bags
> > would balance left/right but nope....right side stayed the same and so
> >>> did left with no visible pressure increase on gauge.
> >>>
> >>>
> >>> All solinoids have power and click.....right side raise solenoid (one
> > with blue line) works and allows air when i blow in it....lower solenoid
> >>> (middle of the three) allows air to flow when i blow in it....the last
> > solinoid works(one with yellow line) but i cant verify air passage because
> >>> i have remove a bunch of other stuff in the way.....
> >>>
> >>> So heres my thought on this.....one would suspect the bag or line to
> > the bag as having a leak because the gauge never builds pressure (right
> >>> side or travel mode) but there is zero audible air leakage....which
> > would leave me, you would think with a plugged solinoid but that would build
> >>> pressure, which it doesnt.
> >>>
> >>> The other question i have is how much air should be coming out of the
> > system at the solinoids? I would think enough that if you plugged the
> >>> hole with your thumb you'd feel it.....no?
> >>
> >> Rich,
> >>
> >> Yes, if you disconnect the line that goes to an airspring(bag) and that
> > side is switched to "Raise", then there should be significant pressure at
> >> that port.
> >> Or, if it is switched to "Travel" and that side is down, then the height
> > control valve should be supplying about that same pressure.
> >>
> >> Are these still the OE Airsprings (bags)??
> >> One know issue with the Sully system is the air port of the spring can
> > get blocked when the suspension is flat.
> >>
> >> The system is controlled by the ride height control valves in each rear
> > wheel well. Do not expect one side to react to the state of the other.
> >>
> >> Matt
> >
> > OE style Firestones...which are weathered but appear to be holding air
> > well enough to drive the coach back 700 miles from were we bought it.
> > --
> > Rich Mondor,
> >
> > Brockville, ON
> >
> > 77 Hughes 2600
> >
> > _______________________________________________
> > 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

Actually made it home, without a bleed down....but my attempts to fix at home have basically be replca broken fittings and the DANA with another known
good one......conclusion is the compressors just havent got the b*lls to fill these things from zero nor really keep up.....hence the Viair question.

--
Rich Mondor,

Brockville, ON

77 Hughes 2600

 

[Keith V]

Buy the biggest air compressor you can afford.
I've never heard anyone say my compressor is too big!
so 450c or 485c is awesome
________________________________
From: Gmclist on behalf of tonka6cuda6--- via Gmclist
Sent: Tuesday, July 30, 2019 2:45 PM
To: gmclist
Cc: tonka6cuda6
Subject: Re: [GMCnet] Rear air suspension question....things just arent adding up.

> Just disconnect the air line at the air bag. Unscrew the fitting that goes
> into the air bag. Screw a Schrader valve into the air bag. Inflate to 90
> psi. Drive it home. Fix it there.
> Jim Hupy
>
> On Tue, Jul 30, 2019, 12:04 PM tonka6cuda6--- via Gmclist <

>

> >>> So been working on the rear air suspension of my Electro Level 1
> > system because i accidently dropped the right side (well i just tried the
> >>> switch....it dumped the whole bag in a split second) and it wont
> > refill.
> >>>
> >>> I replaced the DANA compressor with a known good one because mine was
> > weak along with a faulty check valve and pressure gauge. Got it all back
> >>> together and still no lift....right side doesnt build pressure but the
> > left side doesnt.
> >>>
> >>> So i hit "travel mode" to see what would happen....i assumed the bags
> > would balance left/right but nope....right side stayed the same and so
> >>> did left with no visible pressure increase on gauge.
> >>>
> >>>
> >>> All solinoids have power and click.....right side raise solenoid (one
> > with blue line) works and allows air when i blow in it....lower solenoid
> >>> (middle of the three) allows air to flow when i blow in it....the last
> > solinoid works(one with yellow line) but i cant verify air passage because
> >>> i have remove a bunch of other stuff in the way.....
> >>>
> >>> So heres my thought on this.....one would suspect the bag or line to
> > the bag as having a leak because the gauge never builds pressure (right
> >>> side or travel mode) but there is zero audible air leakage....which
> > would leave me, you would think with a plugged solinoid but that would build
> >>> pressure, which it doesnt.
> >>>
> >>> The other question i have is how much air should be coming out of the
> > system at the solinoids? I would think enough that if you plugged the
> >>> hole with your thumb you'd feel it.....no?
> >>
> >> Rich,
> >>
> >> Yes, if you disconnect the line that goes to an airspring(bag) and that
> > side is switched to "Raise", then there should be significant pressure at
> >> that port.
> >> Or, if it is switched to "Travel" and that side is down, then the height
> > control valve should be supplying about that same pressure.
> >>
> >> Are these still the OE Airsprings (bags)??
> >> One know issue with the Sully system is the air port of the spring can
> > get blocked when the suspension is flat.
> >>
> >> The system is controlled by the ride height control valves in each rear
> > wheel well. Do not expect one side to react to the state of the other.
> >>
> >> Matt
> >
> > OE style Firestones...which are weathered but appear to be holding air
> > well enough to drive the coach back 700 miles from were we bought it.
> > --
> > Rich Mondor,
> >
> > Brockville, ON
> >
> > 77 Hughes 2600
> >
> > _______________________________________________
> > 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

Actually made it home, without a bleed down....but my attempts to fix at home have basically be replca broken fittings and the DANA with another known
good one......conclusion is the compressors just havent got the b*lls to fill these things from zero nor really keep up.....hence the Viair question.

--
Rich Mondor,

Brockville, ON

77 Hughes 2600

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

 

[johnny]

Rich, when the leaks are fixed the system requires verylitte air volume on the road. Once it's pressured, and there's a tank, you should get the ON
light only every now and again, and on reasonable flat road not at all. Rendering it leakless can be a challenge. Put shutoffs and Schraders on each
side, and you can still use it while you troubleshoot.

--johnny
--
Foolish Carriage, 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

 

[6cuda6]

> Rich, when the leaks are fixed the system requires verylitte air volume on the road. Once it's pressured, and there's a tank, you should get the
> ON light only every now and again, and on reasonable flat road not at all. Rendering it leakless can be a challenge. Put shutoffs and Schraders on
> each side, and you can still use it while you troubleshoot.
>
>
> --johnny

Will do Johnny, thanks for the tip and info.

Bags are holding fine ( been 3 days now) but gauge on tank shows "0" so there is a leak someplace still....if i had to guess its either another
cracked fitting at a solinoid or the red line union just as it comes into the left/right split at the left leveling valve.....

--
Rich Mondor,

Brockville, ON

77 Hughes 2600

 

[johnny]

A spray bottle of kid's 'bubble juice' is Your Friend. Or, you can disconnect and plug suspects and try to pressure it again, isolating leaks. If it
dumped all at once I would suspect a fairly spectacular leak.

--johnny

--
Foolish Carriage, 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

 

[Ken B]

When the compressor is running does the gauge ever rise at all?
If the answer is no, then suspect:
1. A bad gauge
2. A bad compressor
3. One heck of a leak

If the compressor pressure rises and then leaks down, then
suspect:
1. A bad check valve if installed.
2. A backwards leak through the stopped compressor.
3. A leak in any of the lines between the compressor and the valve / solenoid assembly. (unless you installed those shut of thing and have them
turned off.)
4. A bad compressor.
5. Bad air pressure switch or unloader, if equipped.

It has been a while but I believe the compressor line goes to the Check valve then the tank and the tank connects to the manifold. I have no idea
where the gauge is connected to since it is not OEM.

You could disconnect the line at the tank and put a plug or better yet a pressure gauge in the hole where you disconnected the line. Then run the
compressor see if it will build up pressure and hold it. Run it up to about 120 PSI and shut and manually shut off the compressor. The normal
pressure switch will not shut it off because it is on the side that you disconnected. If builds up and holds pressure you know everything up to that
point is OK. If it is OK, put it back together and move on to things connected at the manifold. If not, find the problems from the tank to the
compressor and fix them.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana

 

[6cuda6]

> When the compressor is running does the gauge ever rise at all?
> If the answer is no, then suspect:
> 1. A bad gauge
> 2. A bad compressor
> 3. One heck of a leak
>
> If the compressor pressure rises and then leaks down, then
> suspect:
> 1. A bad check valve if installed.
> 2. A backwards leak through the stopped compressor.
> 3. A leak in any of the lines between the compressor and the valve / solenoid assembly. (unless you installed those shut of thing and have them
> turned off.)
> 4. A bad compressor.
> 5. Bad air pressure switch or unloader, if equipped.
>
> It has been a while but I believe the compressor line goes to the Check valve then the tank and the tank connects to the manifold. I have no idea
> where the gauge is connected to since it is not OEM.
>
> You could disconnect the line at the tank and put a plug or better yet a pressure gauge in the hole where you disconnected the line. Then run the
> compressor see if it will build up pressure and hold it. Run it up to about 120 PSI and shut and manually shut off the compressor. The normal
> pressure switch will not shut it off because it is on the side that you disconnected. If builds up and holds pressure you know everything up to
> that point is OK. If it is OK, put it back together and move on to things connected at the manifold. If not, find the problems from the tank to the
> compressor and fix them.

Thanks Ken...ill assess it with your helpful list and see were we end up.

Cheers

--
Rich Mondor,

Brockville, ON

77 Hughes 2600