Need Help With Airbag Controls/Compressor
- Thread starter bryan hartman
- Start date
Scott - where do I get the reading from. Didn't see anything on the tank except for the very bottom. Looked like a drain though.
--
1977 Palm Beach
--
1977 Palm Beach
Bryan,
First thing to check is the filter on the inlet of the compressor.
They are a foam piece that disintegrates and gets sucked into
the compressor. Bad JuJu. John Clement has some synthetic
ones that are much better.
Gary Kosier
77PB w/500Cad
Newark, Ohio
--------------------------------------------------
From: "Bryan Hartman"
Sent: Tuesday, March 07, 2017 8:06 PM
To:
Subject: Re: [GMCnet] Need Help With Airbag Controls/Compressor
> Scott - where do I get the reading from. Didn't see anything on the tank
> except for the very bottom. Looked like a drain though.
> --
> 1977 Palm Beach
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
First thing to check is the filter on the inlet of the compressor.
They are a foam piece that disintegrates and gets sucked into
the compressor. Bad JuJu. John Clement has some synthetic
ones that are much better.
Gary Kosier
77PB w/500Cad
Newark, Ohio
--------------------------------------------------
From: "Bryan Hartman"
Sent: Tuesday, March 07, 2017 8:06 PM
To:
Subject: Re: [GMCnet] Need Help With Airbag Controls/Compressor
> Scott - where do I get the reading from. Didn't see anything on the tank
> except for the very bottom. Looked like a drain though.
> --
> 1977 Palm Beach
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
Bryan,
I can't remember if it's a drain or drain/pressure relief valve. What I would do,as I'm doing now, is to put shut off valves with a air intake
valve(schrader valve) at the bags. Pump up the bags at the new air valve, and run it like that until you have time to trouble shoot more. You can pump
it up from outside the coach to get the proper ride height. Your bags are also fairly new, so they should hold the pressure for at least two weeks I
would think. I also installed a air pressure gauge at the bags. Then I just add air as needed to maintain ride height.
Please call me if I can be of help. I can email pictures if needed. I still have a systems monitor headed your way. The delay is due to old timers
disease!!
Scott.
--
Scott Nutter
1978 455 Royale Center Kitchen, Quad bags.
Houston, Texas
I can't remember if it's a drain or drain/pressure relief valve. What I would do,as I'm doing now, is to put shut off valves with a air intake
valve(schrader valve) at the bags. Pump up the bags at the new air valve, and run it like that until you have time to trouble shoot more. You can pump
it up from outside the coach to get the proper ride height. Your bags are also fairly new, so they should hold the pressure for at least two weeks I
would think. I also installed a air pressure gauge at the bags. Then I just add air as needed to maintain ride height.
Please call me if I can be of help. I can email pictures if needed. I still have a systems monitor headed your way. The delay is due to old timers
disease!!
Scott.
--
Scott Nutter
1978 455 Royale Center Kitchen, Quad bags.
Houston, Texas
Thanks Scott. I wasn't sure of the age of the air bags. I looked at them (being and old tire guy) and was not comfortable with the amount of
"cracking". It might just be cosmetic but it looked like I could see the carcass in some of the bigger ones. I went ahead and ordered 2 new bags with
the shut-off valves from Applied. Once I have those installed I can spend a bit of time working out the kinks, wonks, & leaks. If it is still giving
me issues after the good ol' college try I might consider the wireless air system (but that is a bit downstream).
No worries about your "disease"...I think I might share your affliction.
--
1977 Palm Beach
"cracking". It might just be cosmetic but it looked like I could see the carcass in some of the bigger ones. I went ahead and ordered 2 new bags with
the shut-off valves from Applied. Once I have those installed I can spend a bit of time working out the kinks, wonks, & leaks. If it is still giving
me issues after the good ol' college try I might consider the wireless air system (but that is a bit downstream).
No worries about your "disease"...I think I might share your affliction.
--
1977 Palm Beach
Ok. The new air bags are "installed" with shut off valves. I still need to connect the air lines and torque everything down properly but I wanted to
give it a day or two to make sure they were holding air...they seem to be so far.
While I am waiting I decided to start trying to pinpoint the compressor issue. I pulled the compressor from the coach and connected it to a battery. I
let it run for 2 minutes and it seems to run fine. The compressor was only a little warm on the cooling fins and it was pushing out more air pressure
than I could prevent using my thumb. The connections to the battery I was using started to get quite warm towards the end but I doubt the wires were
12 gauge so I assume that is normal. I didn't want to push my luck and go any longer.
Can I assume the compressor is not the problem at this point?
--
1977 Palm Beach
give it a day or two to make sure they were holding air...they seem to be so far.
While I am waiting I decided to start trying to pinpoint the compressor issue. I pulled the compressor from the coach and connected it to a battery. I
let it run for 2 minutes and it seems to run fine. The compressor was only a little warm on the cooling fins and it was pushing out more air pressure
than I could prevent using my thumb. The connections to the battery I was using started to get quite warm towards the end but I doubt the wires were
12 gauge so I assume that is normal. I didn't want to push my luck and go any longer.
Can I assume the compressor is not the problem at this point?
--
1977 Palm Beach
Nope. You need to put the compressor under load for much longer than 2
minutes -- using 12+g. wire. Do you perhaps have a portable air tank, or
similar, to which you can connect it? Since you won't be running through a
pressure cutoff switch, monitor the pressure closely so you don't exceed
the rating of the receiving tank. Without that, you need to re-install the
compressor, let all the air out of the bags, provide power directly from
the batteries, and see if it will re-inflate the bags. If not, the
compressor is not up to the job.
Ken H.
> ...
>
> While I am waiting I decided to start trying to pinpoint the compressor
> issue. I pulled the compressor from the coach and connected it to a
> battery. I
> let it run for 2 minutes and it seems to run fine. The compressor was only
> a little warm on the cooling fins and it was pushing out more air pressure
> than I could prevent using my thumb. The connections to the battery I was
> using started to get quite warm towards the end but I doubt the wires were
> 12 gauge so I assume that is normal. I didn't want to push my luck and go
> any longer.
>
> Can I assume the compressor is not the problem at this point?
> --
>
minutes -- using 12+g. wire. Do you perhaps have a portable air tank, or
similar, to which you can connect it? Since you won't be running through a
pressure cutoff switch, monitor the pressure closely so you don't exceed
the rating of the receiving tank. Without that, you need to re-install the
compressor, let all the air out of the bags, provide power directly from
the batteries, and see if it will re-inflate the bags. If not, the
compressor is not up to the job.
Ken H.
> ...
>
> While I am waiting I decided to start trying to pinpoint the compressor
> issue. I pulled the compressor from the coach and connected it to a
> battery. I
> let it run for 2 minutes and it seems to run fine. The compressor was only
> a little warm on the cooling fins and it was pushing out more air pressure
> than I could prevent using my thumb. The connections to the battery I was
> using started to get quite warm towards the end but I doubt the wires were
> 12 gauge so I assume that is normal. I didn't want to push my luck and go
> any longer.
>
> Can I assume the compressor is not the problem at this point?
> --
>
Thank you Ken. I reinstalled the compressor but I did not connect the output back to the tank. It ran for 5 minutes just blowing air through the open
line with no issues. Based on your reply I assume that that still probably wasn't enough of a load. It Once I get the air lines reconnected to the
tank and the bags I will try again.
On a related, when I have the Travel switch on "Hold" and I click "Raise" on either switch the compressor kicks on and blows like I would expect. I
also noticed exactly the same behavior when I put either switch on "Lower" which I would not expect. That is not normal, correct? The compressor
should not come on and blow when the switches are set to "Lower" right?
--
1977 Palm Beach
line with no issues. Based on your reply I assume that that still probably wasn't enough of a load. It Once I get the air lines reconnected to the
tank and the bags I will try again.
On a related, when I have the Travel switch on "Hold" and I click "Raise" on either switch the compressor kicks on and blows like I would expect. I
also noticed exactly the same behavior when I put either switch on "Lower" which I would not expect. That is not normal, correct? The compressor
should not come on and blow when the switches are set to "Lower" right?
--
1977 Palm Beach
Bryan,
The compressor running when Lowering is not LOGICAL, but it's apparently
NORMAL.
At least that's the way mine works too. I keep thinking I'll
get a RoundTuit and fix it, but it hasn't happened during the past 19 years.
Ken H.
> Thank you Ken. I reinstalled the compressor but I did not connect the
> output back to the tank. It ran for 5 minutes just blowing air through the
> open
> line with no issues. Based on your reply I assume that that still probably
> wasn't enough of a load. It Once I get the air lines reconnected to the
> tank and the bags I will try again.
>
> On a related, when I have the Travel switch on "Hold" and I click "Raise"
> on either switch the compressor kicks on and blows like I would expect. I
> also noticed exactly the same behavior when I put either switch on "Lower"
> which I would not expect. That is not normal, correct? The compressor
> should not come on and blow when the switches are set to "Lower" right?
> --
> 1977 Palm Beach
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
The compressor running when Lowering is not LOGICAL, but it's apparently
NORMAL.
At least that's the way mine works too. I keep thinking I'llget a RoundTuit and fix it, but it hasn't happened during the past 19 years.
Ken H.
> Thank you Ken. I reinstalled the compressor but I did not connect the
> output back to the tank. It ran for 5 minutes just blowing air through the
> open
> line with no issues. Based on your reply I assume that that still probably
> wasn't enough of a load. It Once I get the air lines reconnected to the
> tank and the bags I will try again.
>
> On a related, when I have the Travel switch on "Hold" and I click "Raise"
> on either switch the compressor kicks on and blows like I would expect. I
> also noticed exactly the same behavior when I put either switch on "Lower"
> which I would not expect. That is not normal, correct? The compressor
> should not come on and blow when the switches are set to "Lower" right?
> --
> 1977 Palm Beach
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
The battery is off mine so I can't check it... but I >think< the compressor doesn't run in Lower. However, there are a bunch of solenoids in the
system, and I can see where if one were to stick or have its wires crossed with another, Lower would bleed off air from the pressure switch and that
would fire off the compressor - whose out put would go overboard along with the bag air.
Look at the setup in the manual, and do a truth table for each position of the switches and figure how to run the air out of the reservoir.
--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
system, and I can see where if one were to stick or have its wires crossed with another, Lower would bleed off air from the pressure switch and that
would fire off the compressor - whose out put would go overboard along with the bag air.
Look at the setup in the manual, and do a truth table for each position of the switches and figure how to run the air out of the reservoir.
--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
My '77 Palm Beach also runs the air compressor with either switch in Lower mode. Checking the the wiring diagram and that's how its wired from
factory.
It's never bothered me enough to go any further than check the schematics.
--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.
Hubler 1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that
factory.
It's never bothered me enough to go any further than check the schematics.
--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.
Hubler 1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that
Ok...new info.
I hooked up the compressor to the tank and the right side air line to the completely deflated air bag. I left the left side air line unattached.
When I activate the switch to inflate the right side, everything works as expected and the bag inflates until about 82 psi then it shuts off. I can
immediately switch off the right side, activate the left side inflate switch, and after about a second the compressor fires back up and starts pumping
air out the unattached left hose. I can then immediately switch everything back to inflate the right side and the compressor runs for 10 secs and
shuts off.
??? Bad compressor? Something else?
--
1977 Palm Beach
I hooked up the compressor to the tank and the right side air line to the completely deflated air bag. I left the left side air line unattached.
When I activate the switch to inflate the right side, everything works as expected and the bag inflates until about 82 psi then it shuts off. I can
immediately switch off the right side, activate the left side inflate switch, and after about a second the compressor fires back up and starts pumping
air out the unattached left hose. I can then immediately switch everything back to inflate the right side and the compressor runs for 10 secs and
shuts off.
??? Bad compressor? Something else?
--
1977 Palm Beach
> Bryan,
>
> The compressor running when Lowering is not LOGICAL, but it's apparently
> NORMAL. At least that's the way mine works too. I keep thinking I'll
> get a RoundTuit and fix it, but it hasn't happened during the past 19 years.
>
> Ken H.
I also believe that is normal. I have not looked at the circuit, but mine does the same thing. The compressor should run anytime the pressure in
the tank is low to refill the tank.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
>
> The compressor running when Lowering is not LOGICAL, but it's apparently
> NORMAL.
At least that's the way mine works too. I keep thinking I'll> get a RoundTuit and fix it, but it hasn't happened during the past 19 years.
>
> Ken H.
I also believe that is normal. I have not looked at the circuit, but mine does the same thing. The compressor should run anytime the pressure in
the tank is low to refill the tank.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
As long a the compressor is stopping and not blowing the CB, then the on and off of the compressor is determined by the pressure at the air pressure
at the air pressure switch (and tank). It makes no difference if one switch is set low and the other normal (or high), or if both are low, or if both
high.
Compressor off and on is determined by the tank pressure only.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
at the air pressure switch (and tank). It makes no difference if one switch is set low and the other normal (or high), or if both are low, or if both
high.
Compressor off and on is determined by the tank pressure only.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
True dat. A stuck solenoid can allow the tank to bleed out the LOWER solenoid settung thereby lowering the tank pressure and causing the compressor
to run when LOWER is selected. A look at the pressure switch with its cover off seems to be in order here. It may simply be pressuring the tank and
turning off as it should.
--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
to run when LOWER is selected. A look at the pressure switch with its cover off seems to be in order here. It may simply be pressuring the tank and
turning off as it should.
--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
Next update (can't wait until I can say "Last Update"):
With you guys' help, I started to think that maybe the system was shutting off the compressor by design. I realized that I still had the coach sitting
really high. When I replaced the bags I used the "6 2x4's" height that Sully recommends in his bag replacement video and I was testing from that. I
was trying to get the system to pick the coach off the 2x4's so I could remove them and then test the lowering. Maybe the height of the coach was
above the maximum allowed pressure?
So I lifted the coach a bit, removed 2 of the boards, and lowered everything 3". I then flipped the "Raise" switch. The compressor ran for just over 2
minutes and raised then coach about 3" before it shut off. I then manually lowered the coach and repeated with the exact same results. (*The "Lower"
switch on that side does not seem to be working yet)
Does that mean the "Raise" is working now and I had just reached the maximum height? Where do I measure to figure out height? Ground to skirt mount
height? Ground to bottom of body molding strip?
--
1977 Palm Beach
With you guys' help, I started to think that maybe the system was shutting off the compressor by design. I realized that I still had the coach sitting
really high. When I replaced the bags I used the "6 2x4's" height that Sully recommends in his bag replacement video and I was testing from that. I
was trying to get the system to pick the coach off the 2x4's so I could remove them and then test the lowering. Maybe the height of the coach was
above the maximum allowed pressure?
So I lifted the coach a bit, removed 2 of the boards, and lowered everything 3". I then flipped the "Raise" switch. The compressor ran for just over 2
minutes and raised then coach about 3" before it shut off. I then manually lowered the coach and repeated with the exact same results. (*The "Lower"
switch on that side does not seem to be working yet)
Does that mean the "Raise" is working now and I had just reached the maximum height? Where do I measure to figure out height? Ground to skirt mount
height? Ground to bottom of body molding strip?
--
1977 Palm Beach
I think I found it:
http://www.gmcmhphotos.com/photos/misc/p28167-ride-height-maint-manual-page-3a-21.html
So for the rear it should be 11-11/16 from the top of the slot in the frame?
--
1977 Palm Beach
http://www.gmcmhphotos.com/photos/misc/p28167-ride-height-maint-manual-page-3a-21.html
So for the rear it should be 11-11/16 from the top of the slot in the frame?
--
1977 Palm Beach
Bryan,
After 19 years, I still can't say "Last update" with a straight face.
Page 3A-19 of your '77-'78 Maintenace Manual has the diagram of where to
measure and the heights. If you don't yet have that manual, you're
handicapping yourself in your troubleshooting. Download it from bdub.net.
Ken H.
> Next update (can't wait until I can say "Last Update"):
> ...
>
> Does that mean the "Raise" is working now and I had just reached the
> maximum height? Where do I measure to figure out height? Ground to skirt
> mount
> height? Ground to bottom of body molding strip?
> --
> 1977 Palm Beach
>
>
After 19 years, I still can't say "Last update" with a straight face.
Page 3A-19 of your '77-'78 Maintenace Manual has the diagram of where to
measure and the heights. If you don't yet have that manual, you're
handicapping yourself in your troubleshooting. Download it from bdub.net.
Ken H.
> Next update (can't wait until I can say "Last Update"):
> ...
>
> Does that mean the "Raise" is working now and I had just reached the
> maximum height? Where do I measure to figure out height? Ground to skirt
> mount
> height? Ground to bottom of body molding strip?
> --
> 1977 Palm Beach
>
>
