Rear Squat on Air Suspension

[kacyk]

Anyone know what the tolerance or acceptable measurement is from ground to the fender arch line (F&R)? I had a Land Rover Discovery with air suspension and the rear "squatted" a bit compared to the front. The dealer said it was normal. My Honda Odyssey minivan squats also. I'm seeing the same thing on my H2 (see pic). Is this the case with all H2's with air suspensions? I hate the look of a squatting truck but I don't want to raise the rear every time drive. The picture below is before I installed the 3rd row bench. The squat is the same. I am worried, however, that once I get the spare tire mounted in the rear the squat is going to be worse.

[kacyk]

Anyone know what the tolerance or acceptable measurement is from ground to the fender arch line (F&R)? I had a Land Rover Discovery with air suspension and the rear "squatted" a bit compared to the front. The dealer said it was normal. My Honda Odyssey minivan squats also. I'm seeing the same thing on my H2 (see pic). Is this the case with all H2's with air suspensions? I hate the look of a squatting truck but I don't want to raise the rear every time drive. The picture below is before I installed the 3rd row bench. The squat is the same. I am worried, however, that once I get the spare tire mounted in the rear the squat is going to be worse.

[kacyk]

Anyone know what the tolerance or acceptable measurement is from ground to the fender arch line (F&R)? I had a Land Rover Discovery with air suspension and the rear "squatted" a bit compared to the front. The dealer said it was normal. My Honda Odyssey minivan squats also. I'm seeing the same thing on my H2 (see pic). Is this the case with all H2's with air suspensions? I hate the look of a squatting truck but I don't want to raise the rear every time drive. The picture below is before I installed the 3rd row bench. The squat is the same. I am worried, however, that once I get the spare tire mounted in the rear the squat is going to be worse.

[KenP]

Something sound funny. The H2, along with most of GM's truck line, has a rake to it. The rear should be higher than the front. If yours is not something is amiss. Adding the extra weight should not change that rake as the rear is self leveling.

[DURAMAX TIM]

Have the dealer adjust the level, if u want to do it, I'll have to look at the wife's and see what needs to be moved.
Someone on here has done it before.

[Spike]

I have the air ride in my H2 and it is higher in the back.

[kacyk]

I just measured the distance between the top of the tires to the fender. In the rear its 8.25 inches and the front is 9.25 inches. Is that different for you?

[It\'s a Dry Heat]

From setting over night mine was 8.25 back and 8.75 front both sides.Air ride.

[timgco]

I had the same measurements as It's A Dry heat.
Mine has been updated by the stealership too. my compressor ran all of the time, but this is how it sits.

[kacyk]

The dealer diagnosed the issue and they are replacing some computer that controls the suspension balance of the truck (I'm sure there is a technical term for this). Apparently the front of the truck is too high. Can't wait to get rid of the "squat" look. Interesting enough, I looked at other pics of H2's on Ebay and this forum and discovered that other H2's have a squatting look as well. TSB???

[KenP]

Here is what I have:

frt: 8"
rr: 7 7/8"
Then measured at the roof, above the tracks next to marker lights:
frt: 75" (w/in 1/4")
rr: 77" "

The rack then would be coming from the body design, not suspension.

[kacyk]

The new unit they installed failed. Due to the long weekend they can't get another one in until next Tuesday. John at Hummer of Bellevue is a great guy. I hate the wait but at least they are addressing the issue. My Land Rover spent literally 2/3 of its life at the shop so I'm used to it...I guess. Also, I had them check the brakes and they told me that generally the H2 brakes last about 50K miles! Wow, is that true?

[kacyk]

Got it back after a week in the shop. They replaced the main control unit and rear air shocks as well. The distance between the top of the wheel and the fender in the rear is higher now at 8.75 inches. The FL is 9.25 and the FR is 9.50. Damn! Does anyone know if the balance can be manipulated? I just want it to be equal all around. After a week I thought they'd have it fixed.

[TBarrow]

The brake comment, I have over 60,XXX on mine and still have the factory brakes and I drive hard.

[Hummie2]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by kacyk:
Got it back after a week in the shop. They replaced the main control unit and rear air shocks as well. The distance between the top of the wheel and the fender in the rear is higher now at 8.75 inches. The FL is 9.25 and the FR is 9.50. Damn! Does anyone know if the balance can be manipulated? I just want it to be equal all around. After a week I thought they'd have it fixed. <HR></BLOCKQUOTE>

Adjust your right front torsion adjuster down about 1 turn, drive for a day then remeasure and go from there.

[kacyk]

Hummie2,

Thanks for the reply! Where is it and how is it done? Will I void the warranty or confuse the air suspension control box if I mess with this? If what you're saying works. I'd like to lowr the front left as well so that all four corners are equal.

[Hummie2]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR> Where is it and how is it done? <HR></BLOCKQUOTE>

See this past thread http://elcova.com/groupee/forums?q=Y&a=tpc&s=2826088551&f=6706011751&m=71910 7543&p=1 . Paragon posted some good pics that show the torsion adjuster bolts.

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR> Where is it and how is it done? <HR></BLOCKQUOTE>

In your case back the bolts out until you obtain the front ride height ("Z" Height) you want. Approx. 42" from ground to lower edge of wheel opening with stock tires @ recomended inflation should be close to correct "Z" height. BE SURE TO HAVE FRONT END ALIGNED after adjusting the bolts, you will change the alignment some. If you have less than 7500 miles dealer should give 1 free alignment under warranty.

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR> Will I void the warranty <HR></BLOCKQUOTE>

No. Dealer should have checked this when they did the rear ride height ("D" Height) repair anyway.

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR> or confuse the air suspension control box <HR></BLOCKQUOTE>

If the rear air suspension is working properly it should level it's self.

[kacyk]

Sorry but my last post was premature. After a few days the air suspension must have leveled itself out. Both rears measure 9.25" and the front comes in at 9.00" just the way I wanted it. There still is the question as to why the dealership released the car when the measurements were off. Perhaps they knew that it took a few days for the air suspension to work itself to a "standard" tolerance?

[dochummer]

Is 42" the proper measurement all around for the vehicle? I just spoke with the service department at a Hummer dealership and told them about my rear squat problem. He mentioned that there's a TSB that has measurements from the chassis to the ground that tells them if the truck is sitting correctly. He didn't recall them off the top of his head. Just want to check and see if my truck falls within the TSB guidelines before I bring it in to the local GM dealership to look at. I've mentioned the rear squat issue before, and they said it was normal. While I was at bellevue hummer, I noticed that all the vehicles on the lot definately rested differently... He did mention that the front wheel well is supposed to sit slightly higher than the rear... I'm also due for an oil change, so I'm thinking if it's something that can be fixed, I'll do it at the same time.... Hate not having my H2 to drive

[PARAGON]

<H1>Trim Height Inspection Procedure</H1><A name=ss1-796914><A>
<H5>Trim Height Measurements</A></H5>


Trim height is a predetermined measurement relating to vehicle ride height.
Incorrect trim heights can cause bottoming out over bumps, damage to the
suspension components and symptoms similar to wheel alignment problems. Check
the trim heights when diagnosing suspension concerns and before checking the
wheel alignment.</P>


Perform the following before measuring the trim heights:</P>

1. <LI type=1>Set the tire pressures to the pressure shown on the certification
   label. Refer to <A>Label - Vehicle Certification</A> in General Information.
   
   <LI type=1>Check the fuel level. Add additional weight if necessary to
   simulate a full tank.
   <LI type=1>Make sure the rear compartment is empty except for the spare
   tire.
   <LI type=1>Make sure the vehicle is on a level surface, such as an alignment
   rack.

<A>
<H5>Z Height Measurement</A></H5>

1. <LI type=1>Lift the front bumper of the vehicle up about 38mm
   (1.5in).
   <LI type=1>Remove your hands.
   <LI type=1>Allow the vehicle to settle into position.
   <LI type=1>Repeat this jouncing operation 2 more times for a total of 3
   times.
   
   <A></A>
   
   <LI type=1>Measure from the pivot bolt center line (3) down to the lower
   corner (5) of the lower ball joint (1) in order to obtain the Z height
   measurement (4).
   <LI type=1>Push the front bumper of the vehicle down about 38mm
   (1.5in).
   <LI type=1>Remove your hands.
   <LI type=1>Allow the vehicle to rise.
   <LI type=1>Repeat the operation for a total of 3 times.
   <LI type=1>Measure the Z dimension.
   <LI type=1>The true Z height dimension number is the average of the high and
   the low measurements. Refer to <A>Trim Height Specifications</A> .

<A name=ss3-796914><A>
<H5>Z Height Adjustment</A></H5>

1. 
   
   <A></A>
   
   <LI type=1>For vehicles equipped with a torsion bar suspension turn the bolt
   (1) that contacts the torsion arm clockwise to raise the and
   counterclockwise to lower the height adjustment. One revolution of the bolt
   (1) into the nut increases the Z height by approximately 6.0mm
   (0.2in).
   <LI type=1>For vehicles without torsion bars, replace damaged or worn
   components as necessary.

<A name=ss4-796914><A>
<H5>D Height Measurement</A></H5>


The D height dimension measurement determines the proper rear end ride
height. There is no adjustment procedure. Repair may require replacement of
suspension components.</P>

1. <LI type=1>With the vehicle on a flat surface, lift upward on the rear
   bumper 38mm (1.5in).
   <LI type=1>Remove your hands.
   <LI type=1>Allow the vehicle to settle into position.
   <LI type=1>Repeat the jouncing operation 2 more times for a total of 3
   times.
   
   <A></A>
   
   <LI type=1>The D height is obtained by measuring the distance between the
   edge of the jounce cup along the jounce bumper center line and the jounce
   pad on the rear axle.
   <LI type=1>The true D height dimension number is the average of the high and
   the low measurements. Refer to <A>Trim Height Specifications</A> .
   <LI type=1>If these measurements are out of specifications, inspect for the
   following conditions:
   <UL type=BULLET>
2. Sagging front suspension Refer to <A>Torsion Bar Replacement</A> in
   Front Suspension.
3. Sagging rear coil springs Refer to <A>Coil Spring Replacement</A> in
   Rear Suspension.
4. Proper air suspension operation.
5. Worn rear suspension components.
6. Improper tire inflation Refer to <A>Tire Inflation Pressure
   Specifications</A> in Maintenance and Lubrication.
7. Improper weight distribution
8. Collision damage

[/list]