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View Full Version : Rear Squat on Air Suspension


kacyk
05-22-2004, 05:32 AM
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
05-22-2004, 05:32 AM
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
05-22-2004, 05:32 AM
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
05-22-2004, 10:39 AM
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
05-22-2004, 10:48 AM
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
05-22-2004, 11:11 AM
I have the air ride in my H2 and it is higher in the back.

kacyk
05-22-2004, 03:48 PM
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
05-22-2004, 05:49 PM
From setting over night mine was 8.25 back and 8.75 front both sides.Air ride.

timgco
05-23-2004, 01:06 AM
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
05-27-2004, 12:38 AM
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
05-27-2004, 07:00 PM
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
05-27-2004, 09:12 PM
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
06-06-2004, 04:28 AM
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
06-06-2004, 09:28 PM
The brake comment, I have over 60,XXX on mine and still have the factory brakes and I drive hard.

Hummie2
06-07-2004, 12:11 AM
<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
06-07-2004, 01:25 AM
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
06-07-2004, 03:21 AM
<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=719107543&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
06-07-2004, 04:31 AM
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
03-08-2005, 03:40 PM
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 http://www.elcova.com/infopop/emoticons/icon_frown.gif

PARAGON
03-08-2005, 04:34 PM
<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>

<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>

<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.
http://www.pplus.com/3.gif
<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>

http://www.pplus.com/1.gif

<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>

<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.
http://www.pplus.com/2.gif
<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>
Sagging front suspension Refer to <A>Torsion Bar Replacement</A> in
Front Suspension.
Sagging rear coil springs Refer to <A>Coil Spring Replacement</A> in
Rear Suspension.
Proper air suspension operation.
Worn rear suspension components.
Improper tire inflation Refer to <A>Tire Inflation Pressure
Specifications</A> in Maintenance and Lubrication.
Improper weight distribution
Collision damage [/list]

Anthony
03-08-2005, 09:51 PM
kayck, Could you please post a pic of the fixed vehicle. I think mine is off and has been since day one. I almost did not opt for the air susp because I thought this was how all of the air susp equiped trucks were supposed to be.

Anthony
03-08-2005, 09:53 PM
here is mine

Anthony
03-08-2005, 09:54 PM
sorry, that worked out well?

Anthony
03-09-2005, 12:46 AM
While we're talking about suspension, anyone else hear a creaking noise when they step on the side step getting into their truck? Before you get too far, I weigh 190.

dochummer
03-09-2005, 01:16 AM
Thanks paragon. I know it's been listed before...but what is the correct D height measurement as well as Z height measurement?

Anthony, do you have another pic? Can't quite see your vehicle completely http://www.elcova.com/infopop/emoticons/icon_smile.gif

PARAGON
03-09-2005, 01:28 AM
Oops, sorry. Info doesn't do much good without that. Let me look it up.

PARAGON
03-09-2005, 01:35 AM
<H1>Trim Height Specifications</H1>
<TABLE width="100%" border=1>
<TBODY>
<TR>
<TH vAlign=center align=middle>


Suspension</P></TH>
<TH vAlign=center align=middle>


Z Height</P></TH>
<TH vAlign=center align=middle>


D Height</P></TH></TR>
<TR>
<TD vAlign=bottom align=left colSpan=3>


Trim Height must be verified and adjusted before aligning the
vehicle.</P></TD></TR>
<TR>
<TD vAlign=center align=middle>


With RPO ZM6</P></TD>
<TD vAlign=center align=middle>


122mm (4.8in) ±6mm (0.24in ) </P></TD>
<TD vAlign=center align=middle>


132mm (5.2in) ±6mm (0.24in ) </P></TD></TR>
<TR>
<TD vAlign=center align=middle>


Without RPO ZM6</P></TD>
<TD vAlign=center align=middle>


122mm (4.8in) ±6mm (0.24in ) </P></TD>
<TD vAlign=center align=middle>


140mm (5.5in) ±6mm (0.24in )
</P></TD></TR></TBODY></TABLE>
<FORM name=bottomNavForm>
<HR>
</FORM>

dochummer
03-09-2005, 01:48 AM
Here's a semi-side shot of mine. Front Left is 9 1/4" and Rear Left is 7 7/8" - from top of tire to fender trim. To me, it looks off....

dochummer
03-09-2005, 01:50 AM
While i'm at it, anybody have suggestions for cleaning the wheel well? Armor-all?

kacyk
03-09-2005, 03:58 AM
Anthony,

I sold the Pewter H2 so I don't have any pics of it after the fix. Unfortunately they wouldn'y fix the new H2. I'm planning on taking it back to the original service advisor that fixed our fist H2 under warranty.

kacyk
03-09-2005, 04:33 AM
I found this pic and it was after the fix...but it's not really a good angle. Actually, it still looks like it's squatting! The side steps will angle down in the front after the ride height is adjusted down in the front.

Anthony
03-09-2005, 08:46 PM
Here is a pic of the day after we picked it up last year. One of the only ones I have on this computer. Sorry it's so large.

Anthony
03-09-2005, 08:51 PM
At this point I'm thinking of lowering the front to make it look better, but that just seems counter productive. First time the skid plate hits something I'm going to think twice about lowering a hummer.

Is there any way to adjust the air susp to stay up an inch higher? could there be a computer adjustment or program to do this?

PARAGON
03-09-2005, 09:01 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by dochummer:
While i'm at it, anybody have suggestions for cleaning the wheel well? Armor-all? </div></BLOCKQUOTE>When the dealer washes my truck, my wheel wells come back clean and black. I know there is some stuff you can spray to "renew" the wheel wells for when you are going to sell, but I am really not sure what process the dealer uses. My wheel wells look like new every time.

PARAGON
03-09-2005, 09:03 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Anthony:
At this point I'm thinking of lowering the front to make it look better, but that just seems counter productive. First time the skid plate hits something I'm going to think twice about lowering a hummer.

Is there any way to adjust the air susp to stay up an inch higher? could there be a computer adjustment or program to do this? </div></BLOCKQUOTE>Well, I guess you could make some adjustment to the little arms for the sensors in each rear wheel well. Not sure if anyone tried this.

dochummer
03-09-2005, 11:40 PM
I thought someone had previously said there was, but there was no verification. I was told by my non-local hummer dealership that my air suspension would probably have to be replaced. I'm sitting about 1.5" lower in the back as compared to the front....

Anthony
03-10-2005, 02:09 AM
Measured mine yesterday. 9.5 front and 8.25 in rear. Does that mean mine needs replaced? or just adjusted?

dochummer
03-10-2005, 02:21 AM
Here's an idea, how about if I just throw 37's on the rear and leave the front with 35's? http://www.elcova.com/infopop/emoticons/icon_smile.gif I'm guessing it'll probably really mess up the drivetrain or something... http://www.elcova.com/infopop/emoticons/icon_smile.gif

dochummer
03-11-2005, 03:38 AM
So, I ran into the garage again http://www.elcova.com/infopop/emoticons/icon_frown.gif. I left the tire carrier open, and backed up. Fortunately, I only had to replace one section of the garage door track, and a screw on the tire carrier (of course, I had to drill it out, then put a new one in, and broke that too, so...) So I ended up taking the carrier off so I could work on getting the broken screw out. When I did so, I noticed that the truck sat about an 1" higher...and it actually looked perfect! Then, I started the truck up and it self-leveled....I'm back at the original measurements http://www.elcova.com/infopop/emoticons/icon_frown.gif. Is there a way to retrain the air suspension?

kacyk
08-21-2005, 06:26 AM
I know this is a an old and tired thread but Bellevue Hummer flat out refused to address the front clearance issue on my wife's yellow H2, stating that it complied with factory specs. Ironically the bastards made torsion adjustments to my pewter H2 but I guess this is a different day.

Anyway, I did come across McGaughy's spindles that would safely drop the front about 2 inches. The question is, will my 35/12.50-18 wheels rub? Any thoughts?

BTW - I only want to drop the front and the fender to tire "gap" is about 1.75 inches greater in the front of the truck so a 2" drop would just level it out. Not sure why but the gap does not look as bad in this pic.

kacyk
08-21-2005, 10:10 PM
Never mind, I bought a 18 MM socket and adjusted the torsion bars myself. It's level now.

dochummer
08-22-2005, 04:08 AM
How about some "after" pics http://www.elcova.com/infopop/emoticons/icon_smile.gif

kacyk
08-22-2005, 04:16 AM
Everything measures out at 8 inches now. I may go a tad lower in the front but I haven't decided. I'll send you a pic once I get back from Leavenworth. Did you make the torsion adjustment as well?

dochummer
08-22-2005, 04:31 AM
Not yet... I haven't decided what I want to do about it yet.... Sometimes, when it's parked on the street it looks fine...other times, it doesn't. Once I find a perfectly level area, then I'll re-measure everything....

The squat is the only thing I have left to figure out...just got the steering wheel half-shaft? replaced last week...

Is leavenworth where they are having the next HH for the seattle area? I can't remember off the top of my head...I know it's in Oct.

TXSUT
08-22-2005, 11:30 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by kacyk:
Never mind, I bought a 18 MM socket and adjusted the torsion bars myself. It's level now. </div></BLOCKQUOTE>

It is my firm belief that when an H2 is sitting perfectly level, the fender gap in the front is taller than the fender gap in the rear. It's made that way, whether the looks are appealiing or not.

I just wanted to throw that out there to avoid confusion about someone saying the truck is level, when in fact they mean the fender gaps are the same. IMO, they are mutually exclusive measurements.

-Pete