Air Bags adjust for Equal pressure

C

claude brousson

New member
Jan 20, 1999
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>>2. YOu ideally want to adjust the front torsion bars so that each front
>>tire
>>carries the same weight. Same for the rears.
>>
>>tom

As I understand how it should be done, ride heights are not adjusted by
checking how much air pressure is in each side of the vehicle, and as well,
I suspect most,or at least many vehicles, will NOT have equal weighting at
each wheel.

To correctly set ride height, it should be adjusted with the leveling
valves at the rear, measuring from the ground up to the the slots in the
frame,done on a level surface. When properly set, both front and rear, the
frame will not have torsional forces twisting it out of shape- regardless of
whether it is rigid or not.As well the frame will be slightly lower at the
rear than at the front, thus helping steering due to the increased castor.

It is an interesting experience to go to a weigh scale when the place is
closed and not being used, and weigh each wheel individually, and then both
front and both back together, noting weight for each scenario. Have your
wife move from one place in the vehicle to another and the side to side
weight on the wheels will change.

Bottom line is,unless the coach is perfectly and evenly weighted on each
side, then each wheel will have different amounts of weight on them in order
to keep the frame in neutral balance.

Claude
 
HI All

Adjustment of rear suspension air heigth valve with 7/16 socket and pliars
to tilt valve arm then retighten.
Today set both in lower position to try something different.

My coach after driven for 50 miles gets a little too high in rear.Planned to
position rear of coach lower.

Did not drive as good and dual air pressure gauge showed
20 pounds difference.That would mean the suspension with the higher air was
carrying more weight.

Parked coach on highway with usual elevation of pavement toward ditch.Picked
old highway with no traffic and away from blind turns for safety.

After 2 adjustments dual air pressure gauge needles act as one except when
swerving right or left.

The dual air gauge for rear air bags are great.A quick glance and see equal
air in each air bag.

If you have the air valve at each air bag ,you could check with a hand held
air pressure gauge.After air valve adjustment a time lag for air to change.

Equal air pressure in each rear air bag should help to make your coach drive
better.

Adjustment on highway with a little elevation may be better than a level
pad.

Lawrence Gaskins
West Union Wv

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>Equal air pressure in each rear air bag should help to make your
>coach drive better.
>Adjustment on highway with a little elevation may be better than a level pad.
> Lawrence Gaskins
> West Union Wv
>

--
Hi Lawrence - Sorry, but I don't think that this is necessarily true.
If one side of the GMC is heavier that the other side (which is very
common) then using equal air pressure in each bag would mean that one
side of the GMC would sit lower than the other.

The GMC manual indicates that the levelers should be adjusted to make
the body of the GMC ride level. This would, of course, mean that one
air bag would have more pressure than the other if the weight on each
side is not the same.

I would think that the coach would drive better if the body is level
rather than have one side sag down lower than the other. Also, if
one side of the rear is lower, the weight transfer to the front
wheels would be different.

I too have independent air gauges for each air bag but I know how
much air pressure is needed in each bag to make my coach ride level,
even if that pressure is slightly different for each bag.

Emery Stora
77 Kingsley
Santa Fe, NM
 
Emery

The air bag adjusters appear to me to change height 1 1/2 inches.
The red needle for left side had the highest reading about 20 PSI.

Soon I will be adding water to storage tank on right side and will note
changes in gage readings.

The coach may twist 1 1/2 inches and not change front ?Could be wrong.

When I set the bolts on torsion bar height both [amount of bolt extending
from x member] were equal and heights up front was equal.

Anyway the adjustments are easily changed and I recall the original sitting.
How much force would an air bag of 10 diamater X 10 pounds per sq inch
equal. 785 pounds force ? This is pushing on levers at each end of air
bag.This is a lot of difference in weight.

Would be like driving a pick up truck with two 55 gallon drum of water near
left taillight.

Think I will be Ducking now probably a glareing erro in logic.

Lawrence Gaskins

>From: "Emery L. Stora"
>Reply-To: gmcmotorhome
>To: gmcmotorhome
>Subject: Re: GMC: Air Bags adjust for Equal pressure
>Date: Wed, 13 Feb 2002 14:01:38 -0700
>
>>Equal air pressure in each rear air bag should help to make your
>>coach drive better.
>>Adjustment on highway with a little elevation may be better than a level
>>pad.
>> Lawrence Gaskins
>> West Union Wv
>>
>
>--
>Hi Lawrence - Sorry, but I don't think that this is necessarily true.
>If one side of the GMC is heavier that the other side (which is very
>common) then using equal air pressure in each bag would mean that one
>side of the GMC would sit lower than the other.
>
>The GMC manual indicates that the levelers should be adjusted to make
>the body of the GMC ride level. This would, of course, mean that one
>air bag would have more pressure than the other if the weight on each
>side is not the same.
>
>I would think that the coach would drive better if the body is level
>rather than have one side sag down lower than the other. Also, if
>one side of the rear is lower, the weight transfer to the front
>wheels would be different.
>
>I too have independent air gauges for each air bag but I know how
>much air pressure is needed in each bag to make my coach ride level,
>even if that pressure is slightly different for each bag.
>
>Emery Stora
>77 Kingsley
>Santa Fe, NM
>
>---------------------------------------------------------------------
>To unsubscribe, e-mail: gmcmotorhome-unsubscribe
>For additional commands, e-mail: gmcmotorhome-help
>

Lawrence Gaskins
West Union W v

_________________________________________________________________
Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp.
 
Tom

I am thinking that if one side is 1 1/2 inches lower in rear it would be
better to be showing equal air pressure in each air bag.I think the coach
may easily twist 1 1/2 inches and not affect the front loading.

Any way I will be DUCKING and give this more thought.The adjustment takes 10
seconds to reposition.

Lawrence Gaskins

>From: tom warner
>Reply-To: gmcmotorhome
>To: gmcmotorhome
>Subject: Re: GMC: Air Bags adjust for Equal pressure
>
>Larry a couple of things.
>
>1. the air bag with the higher pressure does not NECESSARILY carry the most
>weight. However if the coach is setting at the factory prescribed heights
>on
>LEVEL ground it does. On the highway that will change since the road is
>crowned and the coach is no longer level.
>
>2. YOu ideally want to adjust the front torsion bars so that each front
>tire
>carries the same weight. Same for the rears.
>
>tom
>
>

> >HI All
> >
> >Adjustment of rear suspension air heigth valve with 7/16 socket and
>pliars
> >to tilt valve arm then retighten.
> >Today set both in lower position to try something different.
> >
> >My coach after driven for 50 miles gets a little too high in rear.Planned
>to
> >position rear of coach lower.
> >
> >Did not drive as good and dual air pressure gauge showed
> >20 pounds difference.That would mean the suspension with the higher air
>was
> >carrying more weight.
> >
> >Parked coach on highway with usual elevation of pavement toward
>ditch.Picked
> >old highway with no traffic and away from blind turns for safety.
> >
> >After 2 adjustments dual air pressure gauge needles act as one except
>when
> >swerving right or left.
> >
> >The dual air gauge for rear air bags are great.A quick glance and see
>equal
> >air in each air bag.
> >
> >If you have the air valve at each air bag ,you could check with a hand
>held
> >air pressure gauge.After air valve adjustment a time lag for air to
>change.
> >
> >Equal air pressure in each rear air bag should help to make your coach
>drive
> >better.
> >
> >Adjustment on highway with a little elevation may be better than a level
> >pad.
> >
> > Lawrence Gaskins
> > West Union Wv
> >
> >
> >
> >_________________________________________________________________
> >Get your FREE download of MSN Explorer at
>http://explorer.msn.com/intl.asp.
> >
> >
> >---------------------------------------------------------------------
> >To unsubscribe, e-mail: gmcmotorhome-unsubscribe
> >For additional commands, e-mail: gmcmotorhome-help
> >
> >
> >
>
>
>---------------------------------------------------------------------
>To unsubscribe, e-mail: gmcmotorhome-unsubscribe
>For additional commands, e-mail: gmcmotorhome-help
>

Lawrence Gaskins
West Union W v

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Send and receive Hotmail on your mobile device: http://mobile.msn.com
 
>
>Anyway the adjustments are easily changed and I recall the original sitting.
>How much force would an air bag of 10 diamater X 10 pounds per sq
>inch equal. 785 pounds force ? This is pushing on levers at each
>end of air bag.This is a lot of difference in weight.
>
>Would be like driving a pick up truck with two 55 gallon drum of
>water near left taillight.
>
>Think I will be Ducking now probably a glareing erro in logic.
>
> Lawrence Gaskins

--
Your calculation of the 785 pounds is correct but as you say, you
have levers involved so I have no idea as to how much weight of the
GMC on that side would equal. My sides weighed in pretty close but I
still have about 10 psi diff. in the two sides when level. Does the
20 psi difference that you have equate to the rear and front being
within the GMC specs for ride height?
Emery
 
>>Anyway the adjustments are easily changed and I recall the original sitting.
>>How much force would an air bag of 10 diamater X 10 pounds per sq
>>inch equal. 785 pounds force ? This is pushing on levers at
>>each end of air bag.This is a lot of difference in weight.
>>
>>Would be like driving a pick up truck with two 55 gallon drum of
>>water near left taillight.
>>
>>Think I will be Ducking now probably a glareing erro in logic.
>>
>> Lawrence Gaskins

--
Larry - another thought on the pressure and force. The bags press on
the cones which, due to their sloped sides will give a variable force
as the bags wrap and unwrap from their sloped surface. This force is
then transmitted to the wheels by the levers of the the swing arm.
To make a long story short, I haven't the slightest idea what a
pressure difference would translate to in weight support when the
arms are in the position to make the coach level. Perhaps someone
has done some experimentation with this?

Emery
 
Emery

My gauge did read more air pressure on left side about 10 pounds.The water
tank is empty.Last fall with water in tank air was good match looking as
dual needles in air gauge.
Ride heigth carefully set 14 months ago.New lower arm bushings,off set upper
arm bushings,and front end aligned.GMC driving the best just like a 2002
model.

Today I wnted to lower the rear so loosened each air bag adjustment an set
to the maxium low each side.Then the air difference was way different say 15
or 20 psi.

Did not drive as good after the change with unequal air adjustment as one
might expect.

Re set the air bag adjustments:
The left side adjustment all the way down to low.The right side adjustment
raised up till air pressure identical to left air bag.Drives good as ever.

In three weeks will fill water tank for trip south and may adjust right air
bag to equal left air bag,if air pressure shows change.

My final adjustment is very close to where it began only rear sits lower.If
one side twist made it to front suspension the change would be in Camber
change.

I need to park on level pad and hang coat hanger wires in frame holes to see
if anything changed.While wires are in place it would be a good time to see
affect of changing one side air bag heigth affect on front end side to side
ride heigth.

All the above is a result of a little extra time on my hands.But I am happy.

Lawrence Gaskins
West Union Wv

>From: "Emery L. Stora" Reply-To:
>gmcmotorhome
>To: gmcmotorhome
>Subject: Re: GMC: Air Bags adjust for Equal pressure
>Date: Wed, 13 Feb 2002 16:23:12 -0700
>
>>
>>Anyway the adjustments are easily changed and I recall the original
>>sitting.
>>How much force would an air bag of 10 diamater X 10 pounds per sq
>>inch equal. 785 pounds force ? This is pushing on levers at each
>>end of air bag.This is a lot of difference in weight.
>>
>>Would be like driving a pick up truck with two 55 gallon drum of
>>water near left taillight.
>>
>>Think I will be Ducking now probably a glareing erro in logic.
>>
>> Lawrence Gaskins
>
>--
>Your calculation of the 785 pounds is correct but as you say, you
>have levers involved so I have no idea as to how much weight of the
>GMC on that side would equal. My sides weighed in pretty close but I
>still have about 10 psi diff. in the two sides when level. Does the
>20 psi difference that you have equate to the rear and front being
>within the GMC specs for ride height?
>Emery
>
>-----------------------------------------------------

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>I haven't the slightest idea what a pressure difference would translate to
>in weight support when the arms are in the position to make the coach
>level. Perhaps someone has done some experimentation with this?

Emery

Tomorrow I have got to get the lady ready to go to the cabinet shop.
Formica put out some bad glue and they are going to replace all
of my counter tops and my desk. I would guess that I am about
400 pounds heavy on the drivers side. I have Jim's shut off valves
so I can get to the shraders to measure the pressure with a tire
gauge. The one thing I do know is that when my drivers side bogie
was low I had trouble getting up the rail crossing to my farm.
The passenger side front tire would spin out every time. I have a
very rigid frame. Life is better now.

Take Care
Arch
76 Glenbrook

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