Home » Public Forums » GMCnet » Is there a DIRECT relationship between PSI in the air bag and ride height?
| Is there a DIRECT relationship between PSI in the air bag and ride height? [message #191842] |
Sat, 01 December 2012 07:35  |
kerry pinkerton
Messages: 2565
Registered: July 2012
Location: Harvest, Al
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This site is driving me crazy. Way too much information to absorb. I thought I was past all that 
All this talk of alignment got me thinking. Now keep in mind I've had my coach (77 Eleganza II stock suspension, Electro Level II)for a couple months and have only driven it a hundred miles or so. However, when I drove it home it wandered all over the ruts. That said, I did not 'set' the ride height and really don't have any idea what settings the ride height buttons were on.
What I THINK I've learned is that the wander COULD well have been caused by having the rear end too high, resulting in decreased caster.
I understand from reading here and in the manual that if everything is working correctly with the Electro Level II system, and if I follow the directions for operations, the coach should move to the set level and stay there (if I set the switches right). Assuming the level thingies are adjusted correctly, this should ensure my coach is at the proper ride height. Right?
Ok, so if that is correct I'll be good to go. However, I got to thinking (always a dangerous thing for me because it makes me want to tinker). Is there a direct relationship between air bag PSI and right height. That is, if we put a TEE in the air lines going to the bags and ran them up to a couple gauges in the cockpit, would the PSI readings be a fairly accurate measurement of ride height? That is, assuming some minor variation for temperature and cold bags, is X PSI always going be the same for a given ride height?
Or am I just over thinking things as usual?
Kerry Pinkerton - North Alabama
Had 5 over the years. Currently have a '06 Fleetwood Discovery 39L
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| Re: [GMCnet] Is there a DIRECT relationship between PSI in the air bag and ride height? [message #191849 is a reply to message #191842] |
Sat, 01 December 2012 08:12  |
Robin Hood
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Registered: April 2011
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Direct? By definition, no. It's an air spring. There's sort of a
spring-constant equation in there that uses exponents or something.
Twice the pressure isn't going to give you twice the height.
Which probably doesn't help you in the slightest. I'm being a
smartaleck, sorry. :)
On Sat, Dec 1, 2012 at 7:35 AM, Kerry Pinkerton <Pinkertonk@mchsi.com> wrote:
>
>
> This site is driving me crazy. Way too much information to absorb. I thought I was past all that :lol: :lol: :lol:
>
> All this talk of alignment got me thinking. Now keep in mind I've had my coach (77 Eleganza II stock suspension, Electro Level II)for a couple months and have only driven it a hundred miles or so. However, when I drove it home it wandered all over the ruts. That said, I did not 'set' the ride height and really don't have any idea what settings the ride height buttons were on.
>
> What I THINK I've learned is that the wander COULD well have been caused by having the rear end too high, resulting in decreased caster.
>
> I understand from reading here and in the manual that if everything is working correctly with the Electro Level II system, and if I follow the directions for operations, the coach should move to the set level and stay there (if I set the switches right). Assuming the level thingies are adjusted correctly, this should ensure my coach is at the proper ride height. Right?
>
> Ok, so if that is correct I'll be good to go. However, I got to thinking (always a dangerous thing for me because it makes me want to tinker). Is there a direct relationship between air bag PSI and right height. That is, if we put a TEE in the air lines going to the bags and ran them up to a couple gauges in the cockpit, would the PSI readings be a fairly accurate measurement of ride height? That is, assuming some minor variation for temperature and cold bags, is X PSI always going be the same for a given ride height?
>
> Or am I just over thinking things as usual? :lol:
> --
> Kerry Pinkerton
>
> North Alabama, near Huntsville,
>
> 77 Eleganza II, "The Lady", 403CI, also a 76 Eleganza being re-bodied as an Art Deco car hauler
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Robin Hood
Jackson, MS
2003 Buick Lesabre
1968 Pontiac Catalina
1978 GMC Royale motorhome
1977 GMC Palm Beach motorhome
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| Re: [GMCnet] Is there a DIRECT relationship between PSI in the air bag and ride height? [message #191850 is a reply to message #191842] |
Sat, 01 December 2012 08:16 |
emerystora
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Registered: January 2004
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On Dec 1, 2012, at 6:35 AM, Kerry Pinkerton <Pinkertonk@MCHSI.com> wrote:
>
> However, I got to thinking (always a dangerous thing for me because it makes me want to tinker). Is there a direct relationship between air bag PSI and right height. That is, if we put a TEE in the air lines going to the bags and ran them up to a couple gauges in the cockpit, would the PSI readings be a fairly accurate measurement of ride height? That is, assuming some minor variation for temperature and cold bags, is X PSI always going be the same for a given ride height?
>
>
No. As your load changes the air pressure in the bags would have to change to maintain the same ride height. It can also vary from side to side.
The load will change as you draw water from the tank. It also changes as the holding tank is filled or emptied. It will change as you burn off gasoline from the tanks. It changes depending on where you store the things you bring with you -- including passengers.
Emery Stora
77 Kingsley
Frederick, CO
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| Re: [GMCnet] Is there a DIRECT relationship between PSI in the air bag and ride height? [message #191852 is a reply to message #191850] |
Sat, 01 December 2012 08:36 |
kerry pinkerton
Messages: 2565
Registered: July 2012
Location: Harvest, Al
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| emerystora wrote on Sat, 01 December 2012 08:16 |
No. As your load changes the air pressure in the bags would have to change to maintain the same ride height. It can also vary from side to side.
The load will change as you draw water from the tank. It also changes as the holding tank is filled or emptied. It will change as you burn off gasoline from the tanks. It changes depending on where you store the things you bring with you -- including passengers.
Emery Stora
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Ah, makes perfect sence Emery. Thanks!
Kerry Pinkerton - North Alabama
Had 5 over the years. Currently have a '06 Fleetwood Discovery 39L
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| Re: [GMCnet] Is there a DIRECT relationship between PSI in the air bag and ride height? [message #191854 is a reply to message #191842] |
Sat, 01 December 2012 08:42 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
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Kerry,
Your conclusions are correct, down to the very last. The ride height is
directly related to air bag pressure AT A GIVEN WHEELS WEIGHT. Change the
weight (or distribution), change the psi required to maintain ride height.
Ken H.
On Sat, Dec 1, 2012 at 8:35 AM, Kerry Pinkerton wrote:
> ...
> Ok, so if that is correct I'll be good to go. However, I got to thinking
> (always a dangerous thing for me because it makes me want to tinker). Is
> there a direct relationship between air bag PSI and right height. That is,
> if we put a TEE in the air lines going to the bags and ran them up to a
> couple gauges in the cockpit, would the PSI readings be a fairly accurate
> measurement of ride height? That is, assuming some minor variation fortemperature and cold bags, is X PSI always going be the same for a given
> ride height?
>
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Ken Henderson
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www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: Is there a DIRECT relationship between PSI in the air bag and ride height? [message #191855 is a reply to message #191842] |
Sat, 01 December 2012 08:48 |
A Hamilto
Messages: 4508
Registered: April 2011
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| Kerry Pinkerton wrote on Sat, 01 December 2012 07:35 |
...Is there a direct relationship between air bag PSI and right height. That is, if we put a TEE in the air lines going to the bags and ran them up to a couple gauges in the cockpit, would the PSI readings be a fairly accurate measurement of ride height? That is, assuming some minor variation for temperature and cold bags, is X PSI always going be the same for a given ride height?...
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Forget the effect of temperature. And the short answer is "no". If the weight on the rear never changes, then there would be a direct relationship between air bag PSI and rear ride height. But with fuel and water and passengers and luggage, yada yada yada, the weight on the rear changes from one trip to the next, or even while driving (as the fuel tanks deplete and you run your Thermasan to empty the holding tank).
The rear suspension system is designed to keep the ride height the same regardless of weight, BY VARYING THE AIR PRESSURE IN THE BAG. Increase the weight of the GMC on one side enough to compress the bag and therefore activate the leveling valve, and the pressure in the bag will be increased by the compressor system to bring ride height back into spec. Take enough weight off to allow the bag to expand enough to activate the leveling valve and the valve will release some pressure from the bag to lower that side.
Got it?
The RANGE of pressures that the bag stays in if kept within GVWR specs might be pretty narrow, but I don't know if anyone has ever tracked it.
The wireless air system is based on the assumption that ride height doesn't change enough with variations in loading to move it out of OEM spec regardless of luggage, passengers, water and fuel levels, yada yada yada. Set it and forget it. If you do manage to load it in such a way that you move it out of OEM ride height spec, you manually set a new pressure to get it back to spec.
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| Re: [GMCnet] Is there a DIRECT relationship between PSI in the air bag and ride height? [message #191861 is a reply to message #191855] |
Sat, 01 December 2012 09:10 |
Mr ERFisher
Messages: 7117
Registered: August 2005
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and as Jerry Work showed us at the Casa , rally
have 4 of your friends stand on - and off - of your rear bumper,
and you will not see or hear, the OEM air system change.
http://thedovetailjoint.squarespace.com/storage/Prep%20it%20right-as%20delivered.pdf
the OEM system does not correct for load,( gas, water, waste, temp)
it just resets a level after leveling at a camp site.
there is too much hysteresis, and lack of sensitivity in the level valves
to level on the road
the wireless system does a better job with monitoring the pressure
JMHO
gene
The wireless air system is based on the assumption that ride height doesn't
> change enough with variations in loading to move it out of OEM spec
> regardless of luggage, passengers, water and fuel levels, yada yada yada.
> Set it and forget it. If you do manage to load it in such a way that you
> move it out of OEM ride height spec, you manually set a new pressure to get
> it back to spec.
> --
> '73 23' Sequoia
> UA (Upper Alabama)
> "Sometimes 'free' is too expensive."
> _______________________________________________
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Gene Fisher -- 74-23,77PB/ore/ca
“Give a man a fish; you have fed him for today --- give him a URL and
-------
http://gmcmotorhome.info/
Alternator Protection Cable
http://gmcmotorhome.info/APC.html
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| Re: [GMCnet] Is there a DIRECT relationship between PSI in the air bag and ride height? [message #191862 is a reply to message #191861] |
Sat, 01 December 2012 09:12 |
Mr ERFisher
Messages: 7117
Registered: August 2005
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oops wrong link
http://thedovetailjoint.squarespace.com/storage/GMC%20-%20Align%20it%20right%20presentation-as%20presented.pdf
On Sat, Dec 1, 2012 at 7:10 AM, gene Fisher <mr.erfisher@gmail.com> wrote:
> and as Jerry Work showed us at the Casa , rally
> have 4 of your friends stand on - and off - of your rear bumper,
> and you will not see or hear, the OEM air system change.
>
> http://thedovetailjoint.squarespace.com/storage/GMC%20-%20Align%20it%20right%20presentation-as%20presented.pdf
>
> the OEM system does not correct for load,( gas, water, waste, temp)
> it just resets a level after leveling at a camp site.
> there is too much hysteresis, and lack of sensitivity in the level valves
> to level on the road
>
> the wireless system does a better job with monitoring the pressure
>
> JMHO
> gene
>
>
>
> The wireless air system is based on the assumption that ride height
>> doesn't change enough with variations in loading to move it out of OEM spec
>> regardless of luggage, passengers, water and fuel levels, yada yada yada.
>> Set it and forget it. If you do manage to load it in such a way that you
>> move it out of OEM ride height spec, you manually set a new pressure to get
>> it back to spec.
>> --
>> '73 23' Sequoia
>> UA (Upper Alabama)
>> "Sometimes 'free' is too expensive."
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>>
>
>
>
> --
> Gene Fisher -- 74-23,77PB/ore/ca
> “Give a man a fish; you have fed him for today --- give him a URL and
> -------
> http://gmcmotorhome.info/
> Alternator Protection Cable
> http://gmcmotorhome.info/APC.html
>
--
Gene Fisher -- 74-23,77PB/ore/ca
“Give a man a fish; you have fed him for today --- give him a URL and
-------
http://gmcmotorhome.info/
Alternator Protection Cable
http://gmcmotorhome.info/APC.html
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| Re: [GMCnet] Is there a DIRECT relationship between PSI in the air bag and ride height? [message #191866 is a reply to message #191861] |
Sat, 01 December 2012 09:22 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
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Gene,
That's just not the case. The automatic system DOES correct for load --
after a 4 to 18 second delay. Anything that causes a significant change in
loading should cause the leveling system to compensate after that delay.
Even a long road curve will sometimes cause the system to compensate.
I don't know why Jerry's experiment didn't work, but there was a reason
other than the design.
Ken H.
On Sat, Dec 1, 2012 at 10:10 AM, gene Fisher wrote:
> and as Jerry Work showed us at the Casa , rally
> have 4 of your friends stand on - and off - of your rear bumper,
> and you will not see or hear, the OEM air system change.
>
> http://thedovetailjoint.squarespace.com/storage/Prep%20it%20right-as%20delivered.pdf
>
> the OEM system does not correct for load,( gas, water, waste, temp)
> it just resets a level after leveling at a camp site.
> there is too much hysteresis, and lack of sensitivity in the level valves
> to level on the road
>
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: [GMCnet] Is there a DIRECT relationship between PSI in the air bag and ride height? [message #191868 is a reply to message #191866] |
Sat, 01 December 2012 09:24 |
Mr ERFisher
Messages: 7117
Registered: August 2005
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do the test
do the test
I did on my 26 and 23
gene
On Sat, Dec 1, 2012 at 7:22 AM, Ken Henderson <hend4800@bellsouth.net>wrote:
> Gene,
>
> That's just not the case. The automatic system DOES correct for load --
> after a 4 to 18 second delay. Anything that causes a significant change in
> loading should cause the leveling system to compensate after that delay.
> Even a long road curve will sometimes cause the system to compensate.
>
> I don't know why Jerry's experiment didn't work, but there was a reason
> other than the design.
>
> Ken H.
>
> On Sat, Dec 1, 2012 at 10:10 AM, gene Fisher wrote:
>
> > and as Jerry Work showed us at the Casa , rally
> > have 4 of your friends stand on - and off - of your rear bumper,
> > and you will not see or hear, the OEM air system change.
> >
> >
> http://thedovetailjoint.squarespace.com/storage/Prep%20it%20right-as%20delivered.pdf
> >
> > the OEM system does not correct for load,( gas, water, waste, temp)
> > it just resets a level after leveling at a camp site.
> > there is too much hysteresis, and lack of sensitivity in the level valves
> > to level on the road
> >
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
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>
--
Gene Fisher -- 74-23,77PB/ore/ca
“Give a man a fish; you have fed him for today --- give him a URL and
-------
http://gmcmotorhome.info/
Alternator Protection Cable
http://gmcmotorhome.info/APC.html
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| Re: [GMCnet] Is there a DIRECT relationship between PSI in the air bag and ride height? [message #191879 is a reply to message #191868] |
Sat, 01 December 2012 11:10 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
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I have and mine corrects as the weight changes. The biggest thing I notice is the compressor kicks on (after s slight delay) when I fill up with fuel or water. The other times I notice is when I change from 4 lane to some 2 lane highways. I'm not quite sure why, other than it happens. It probably has something to do with different the crown of the roads. Also when I have a lot of cross winds and change the direction I'm traveling the compressor will kick on after the usual built in delay.
Probably the reason your experiment failed is in real life the leveling switches are continuously changing (bouncing up and down) as you go down the road which means it is moving in and out of the dead band area. I know when I set the ride height statically and then take the coach for a ride, when I return after 5 or 10 miles the switches have found a different set point. So I always take the coach for a ride after setting the height and then check the rear height again. I then adjust as necessary to find the correct dynamic height. Usually it takes two three short trips to get it set exactly.
If you do not bounce the switches in and out of the dead band area, you are correct they will not adjust the air in the bags. Also there is an intentionally built in delay for them to react to load and road changes.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] Is there a DIRECT relationship between PSI in the air bag and ride height? [message #191883 is a reply to message #191879] |
Sat, 01 December 2012 11:32 |
James Hupy
Messages: 6806
Registered: May 2010
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I do not know if the term "dead band" accurately describes the EL II
system. It does not rely on air pressure to automatically adjust the coach
ride height when in Travel Mode. The electronic sensors consists of a pair
of light emitting diodes focused onto a pair of photo transistors. There is
a disc shaped device between the pairs of electronic components. The
device, which is known as a "shutter wheel", is mechanically connected to
the bogie arms. As the bogie arms travel up and down, the shutter wheel
rotates and either blocks the light or allows it to shine on the photo
transistor. This turns the compressor on, or actuates a relay that
energizes a solenoid valve that exhausts air from the bag. Very little
motion is required to move the shutter wheel. There is also a time delay
circuit built into the electronic ride height controller that prevents
sudden suspension movements from actuating the compressors or solenoids
when not necessary. Most problems with EL II systems are electrical in
nature, not air valve or long air line leaking problems. There are also
operator caused issues caused by a lack of understanding in how the system
is supposed to work. The manual describes in detail how to use the system.
If all else fails, read the friggin' manual.
Jim Hupy
Salem, OR
78 GMC Royale 403
On Sat, Dec 1, 2012 at 9:10 AM, Ken Burton <n9cv@comcast.net> wrote:
>
>
> I have and mine corrects as the weight changes. The biggest thing I
> notice is the compressor kicks on (after s slight delay) when I fill up
> with fuel or water. The other times I notice is when I change from 4 lane
> to some 2 lane highways. I'm not quite sure why, other than it happens.
> It probably has something to do with different the crown of the roads.
> Also when I have a lot of cross winds and change the direction I'm
> traveling the compressor will kick on after the usual built in delay.
>
> Probably the reason your experiment failed is in real life the leveling
> switches are continuously changing (bouncing up and down) as you go down
> the road which means it is moving in and out of the dead band area. I know
> when I set the ride height statically and then take the coach for a ride,
> when I return after 5 or 10 miles the switches have found a different set
> point. So I always take the coach for a ride after setting the height and
> then check the rear height again. I then adjust as necessary to find the
> correct dynamic height. Usually it takes two three short trips to get it
> set exactly.
>
> If you do not bounce the switches in and out of the dead band area, you
> are correct they will not adjust the air in the bags. Also there is an
> intentionally built in delay for them to react to load and road changes.
> --
> Ken Burton - N9KB
> 76 Palm Beach
> Hebron, Indiana
> _______________________________________________
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| Re: [GMCnet] Is there a DIRECT relationship between PSI in the air bagand ride height? [message #191903 is a reply to message #191842] |
Sat, 01 December 2012 17:30 |
 |
USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Kerry,
"Rut running" is a well known problem with the GMC which is most often attributed to the fact that the front and rear wheel track is
not the same. The front wheel track is narrower than the rear.
However, it could be caused by other problems and suggest you consider performing the procedure below on your GMC.
http://www.gmceast.com/technical/Mueller_Steering_Inspection_Guide.pdf
When you're done you will KNOW the condition of every component in your steering system.
Then set the ride height as per:
MM X-7525 / Section 4 Rear Suspension / Page 4-34 RIDE HEIGHT ADJUSTMENT
Once that's done an alignment is in order with the following settings:
Camber: 0°
Caster: as much as you can get with 0° camber
Toe in/out: 0 in. or a small amount of toe out as the front wheels pull inwards when power is applied
BTW you can buy front wheel spacers that move the front wheels out to the same track as the rear wheels.
http://www.appliedgmc.com/prod.itml/icOid/656
There has been a lot of discussion noting that moving the wheels outwards will increase the loads on the bearings but empirical
research has demonstrated it's not a problem.
However, it has been noted that if there are any steering / alignment problems installing wheel spacers will exacerbate the problem.
I apologize if I have driven you one step closer to being institutionalized! ;-)
Regards,
Rob M.
-----Original Message-----
From: Kerry Pinkerton
This site is driving me crazy. Way too much information to absorb. I thought I was past all that :lol: :lol: :lol:
All this talk of alignment got me thinking. Now keep in mind I've had my coach (77 Eleganza II stock suspension, Electro Level
II)for a couple months and have only driven it a hundred miles or so. However, when I drove it home it wandered all over the ruts.
That said, I did not 'set' the ride height and really don't have any idea what settings the ride height buttons were on.
What I THINK I've learned is that the wander COULD well have been caused by having the rear end too high, resulting in decreased
caster.
I understand from reading here and in the manual that if everything is working correctly with the Electro Level II system, and if I
follow the directions for operations, the coach should move to the set level and stay there (if I set the switches right). Assuming
the level thingies are adjusted correctly, this should ensure my coach is at the proper ride height. Right?
Ok, so if that is correct I'll be good to go. However, I got to thinking (always a dangerous thing for me because it makes me want
to tinker). Is there a direct relationship between air bag PSI and right height. That is, if we put a TEE in the air lines going
to the bags and ran them up to a couple gauges in the cockpit, would the PSI readings be a fairly accurate measurement of ride
height? That is, assuming some minor variation for temperature and cold bags, is X PSI always going be the same for a given ride
height?
Or am I just over thinking things as usual? :lol:
--
Kerry
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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| Re: Is there a DIRECT relationship between PSI in the air bag and ride height? [message #191911 is a reply to message #191842] |
Sat, 01 December 2012 19:43 |
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mike miller
Messages: 3576
Registered: February 2004
Location: Hillsboro, Oregon
Karma: 0
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| Kerry Pinkerton wrote on Sat, 01 December 2012 05:35 |
... Now keep in mind I've had my coach (77 Eleganza II stock suspension, Electro Level II)for a couple months ...
... Is there a direct relationship between air bag PSI and right height. That is, if we put a TEE in the air lines going to the bags and ran them up to a couple gauges in the cockpit, would the PSI readings be a fairly accurate measurement of ride height? ...
|
First I would be VERY surprised if your 1977 Eleganza II REALLY has an Electro Level II system. EL2 systems where not installed until the last half of the 1978 model year. Not that it really matters to THIS discussion. 
Now that you have feedback from many other sources: There IS a relationship between the pressure in the airbag and the ride height of the coach. But it is NOT linear. (If that is what you mean by direct.) Would gauges of the bag pressures be of any use? I do not know...
But if your coach is loaded the same, the same pressure should give you the same ride height... or close. That is the idea behind the wireless air system and it seems to give satisfactory results for many. AND I really do not think the loads in most coaches change enough to really worry about correcting for it. The user of the coach needs to be aware of the limitations of the system installed in the coach. (IE: If it is normally lightly loaded and then is used as a moving van, pulling a trailer with a bit of tongue weight or something else adding a lot more weight to the coach, it would be a good idea to check it the rear is lower than expected.)
That said, I prefer a system with real "height feed-back" system like the OEM systems. (I have one example of each type.)
Mike Miller -- Hillsboro, OR -- on the Black list
(#2)`78 23' Birchaven Rear Bath -- (#3)`77 23' Birchaven Side Bath
More Sidekicks than GMC's and a late model Malibu called 'Boo'
http://m000035.blogspot.com
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| Re: Is there a DIRECT relationship between PSI in the air bag and ride height? [message #191913 is a reply to message #191911] |
Sat, 01 December 2012 19:59 |
kerry pinkerton
Messages: 2565
Registered: July 2012
Location: Harvest, Al
Karma: 15
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Senior Member |
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| Mike Miller wrote on Sat, 01 December 2012 19:43 |
...
First I would be VERY surprised if your 1977 Eleganza II REALLY has an Electro Level II system. EL2 systems where not installed until the last half of the 1978 model year. ...
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You are correct Mike. It is not a II. My bad.
Thanks for the input everyone.
Kerry Pinkerton - North Alabama
Had 5 over the years. Currently have a '06 Fleetwood Discovery 39L
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| Re: [GMCnet] Is there a DIRECT relationship between PSI in the air bag and ride height? [message #191934 is a reply to message #191868] |
Sun, 02 December 2012 07:24 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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| Mr ERFisher wrote on Sat, 01 December 2012 10:24 |
do the test
do the test
I did on my 26 and 23
gene
--
Gene Fisher -- 74-23,77PB/ore/ca
“Give a man a fish; you have fed him for today --- give him a URL and
On Sat, Dec 1, 2012 at 7:22 AM, Ken Henderson wrote:
Gene,
That's just not the case. The automatic system DOES correct for load -- after a 4 to 18 second delay. Anything that causes a significant change in loading should cause the leveling system to compensate after that delay.
Even a long road curve will sometimes cause the system to compensate.
I don't know why Jerry's experiment didn't work, but there was a reason other than the design.
Ken H.
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Gene,
I would have to guess something is wrong with your system.
When I dump the black tank at home, I can usually hear the system venting.
If I leave the system live (as I often do), the compressor will start when I put on a full load of water or fuel.
Admittedly, I have a very light coach so it is a more significant change, but the system still sees it.
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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| Re: [GMCnet] Is there a DIRECT relationship between PSI in the air bag and ride height? [message #191960 is a reply to message #191934] |
Sun, 02 December 2012 11:00 |
Mr ERFisher
Messages: 7117
Registered: August 2005
Karma: 2
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Senior Member |
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> If I leave the system live (as I often do), the compressor will start when
> I put on a full load of water or fuel.
>
strange, I know of *no one* who leaves the ignition on while filling with
fuel
but you miss my point
200lb on the rear bumper (or changing 20 gal of liquid) does not make the
system work or change
and
IIWDFI
Is the guiding principal
if you are happy - that is a good thing
wireless air has it limits, but is simple, cheaper, easy to install, and
better than living on schrader valves ( which are our last line of defense
;>)
and
at $100 per hour, can you afford someone to search for a leaking,
splice,connection, valve, switch, etc?
http://gmc49ers.blogspot.com/
both of my systems work perfectly, but now the 23 no longer leaks :>)
gene
--
Gene Fisher -- 74-23,77PB/ore/ca
“Give a man a fish; you have fed him for today --- give him a URL and
-------
http://gmcmotorhome.info/
Alternator Protection Cable
http://gmcmotorhome.info/APC.html
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