H3 Uneven Rear Suspension Height

[Ryball]

New to the forum but wanted to ask a question that is stumping me. I have a 2007 Hummer H3 with approx 130,000 miles on it. I have cranked the torsion bars to level the front of the vehicle (added increased length shocks in the front), put on 1/2" extended shackles in the rear leaf springs, and had an alignment done.

Recently I noticed the rear passenger side suspension appeared to be sagging. When measuring from the center of the axle/hub to the bottom of the plastic trim in the wheel well, I noted my H3 was sitting 1" lower on the rear passenger than the rear driver side. Due to the age/mileage, I assumed my leaf spring on the rear right was getting tired and starting to sag. I bought OEM replacement springs for both sides and installed them a few days ago. To my dismay after dropping the H3 back down, the same 1" sag on the rear passenger side is still there. All suspension components are properly torqued and the front end is sitting level.

I'm stumped on what the issue is. When I pulled the CARFAX report when I bought it, there was no issue of any accidents on the vehicle so I don't believe the frame is twisted. I can provide actual measurements of wheel clearances if needed. Any thoughts on this would be appreciated.

 

[JPaul]

Are you making sure you're on a properly level surface? Is your fuel tank full? Any gear in the back that's throwing off the balance? Did you check the body mount bushings? Maybe they're starting to go or something and causing the issue. To make sure it's not something like the frame you could get underneath and measure from the top of the axle to the bottom of the frame on each side and see if there is a difference.

 

[chaos254]

There is a tsb about the rear leaning. I'm not at work today but I can find it tomorrow

Sent from my Nexus 6 using Tapatalk

 

[alrock]

There is a tsb about the rear leaning. I'm not at work today but I can find it tomorrow

Sent from my Nexus 6 using Tapatalk

If I recall correctly, that TSB was about the leafs being improperly tightened at the factory. That issue would have gone away with the installation of new leaf springs.

With the install of the new springs, did you also put in new bushings into the frame for the hangars? And when you tightened the bolts for the leaf springs, was the truck sitting on the ground or was it still in the air? It needs to be on the ground with the weight on the suspension. (That's what the factory failed to do.)

 

[4speedfunk]

Yeah. Loosen the spring mounting bolts and go for a short drive...then re-tighten them. The inner sleeves of the bushings have little teeth that bite into the spring pocket. These will lock the bushing in place...and if you tightened the bolt before the truck was on the ground...it can’t find it’s natural resting place.

 

[JPaul]

My belief is that it will also result in premature failure of the bushing since it's being stressed further than it normally would.

 

[scoreh3]

Welcome to H40, I’m sure someone will be able to figure this out for you.

 

[chaos254]

TECHNICAL
Bulletin No.: 07-03-06-001A
Date: November 21, 2008
Subject:
Vehicle Leans Left and/or Right, Front Sits Low on One Side (Measure Ride Height and Relax Rear Leaf Spring Shackles/Bushings)Models:
2007-2009 Chevrolet Colorado
2007-2009 GMC Canyon
2007-2009 HUMMER H3, H3TSupercede:
This bulletin is being revised to add model years and remove VIN breakpoint information. Please discard Corporate Bulletin Number 07-03-06-001 (Section 03 - Suspension).
Condition
Some customers may comment that the vehicle appears to lean on one side. In most cases, the left front of the vehicle sits lower than the right front.
Cause
The rear leaf spring bushings or shackles may become loaded when the rear leaf spring shackle nuts are secured.
Correction
Measure the fender wheel-opening heights, front and rear, to quantify vehicle lean. Fender wheel-opening heights are related to, but distinct from, trim height (a.k.a. Z and D height). The front wheel-opening height is known as P height, and the rear wheel-opening height is known as R height. The P and R heights are not set at the factory, nor is a specification given for them. However, they are the most direct and repeatable measurement of what a customer would see as the vehicle leaning. Perform the following steps before measuring the fender wheel-opening heights:

^	Make sure the vehicle is on a level surface, such as an alignment rack.
^	Set the tire pressures to the pressure shown on the certification label.
^	Refer to Label - Vehicle Certification in General Information.
^	Check the fuel level. Add additional weight if necessary to simulate a full tank.
^	To ensure proper weight distribution, make sure the rear storage compartment and/or truck bed is empty.
^	Close the doors and hood.

P Height and R Height Measurements
P height and R height are measured the same way. They are the distance from the ground to the highest point on their respective wheel-opening, going through the center of their respective wheel. Record the measurements on the repair order.
If the difference from left to right for P and R height is 10 mm (0.39 in) or less, no repairs are suggested as the vehicle is within specification. If the difference exceeds 10 mm (0.39 in) for either measurement, relax the rear spring shackles/bushings following the procedure below.

1.	Raise and support the vehicle on the alignment rack.
2.	Measure the P height (front wheel-opening height). Compare the left front measurement to the right front measurement.
3.	Measure the R height (rear wheel-opening height). Compare the left rear measurement to the right rear measurement.
4.	Loosen the left front rear leaf spring nut.

5.	Loosen the two left rear leaf spring shackle nuts (1).
6.	Loosen the right front rear leaf spring nut.

7.	Loosen the two right rear leaf spring shackle nuts (1).Tip You may need an assistant to help jounce the rear bumper.
8.	Jounce the rear bumper three complete cycles to help exercise the chassis.
9.	Tighten the left and right rear leaf spring shackle nuts.Tighten Tighten the rear shackle nuts to 85 Nm (63 lb ft).
10.	Tighten the left and right front rear leaf spring nuts.Tighten Tighten the front spring nuts to 125 Nm (92 lb ft).
11.	Verify that the lean condition is fixed.
12.	If the condition still exists, perform the trim height inspection by measuring the Z and D heights. Refer to Trim Height Inspection in SI for further diagnosis.

 

[4speedfunk]

Or loosen the bolts...go for a drive an re-tighten em.