Ford F150 Pickup. Instruction - part 1798

measurements. See TRIM HEIGHT SPECIFICATIONS .  

Z Height Adjustment 

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 6.0 mm (0.2 in). See Fig. 5 . 

Fig. 5: Z Height Adjustment 
Courtesy of GENERAL MOTORS CORP. 

2. For vehicles without torsion bars, replace damaged or worn components as necessary.  

D Height Measurement 

1. With the vehicle on a flat surface, lift upward on the rear bumper 38 mm (1.5 in).  

2. Remove your hands.  

3. Allow the vehicle to settle into position.  

4. Repeat the jouncing operation 2 more times for a total of 3 times.  

5. 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. See Fig. 6 . 

NOTE:

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

 

2004 Hummer H2 

2003-04 SUSPENSION General Diagnosis - H2

  

Fig. 6: D Height Measurement 
Courtesy of GENERAL MOTORS CORP. 

6. The true D height dimension number is the average of the high and the low measurements. Refer to 

TRIM HEIGHT SPECIFICATIONS .  

7. If these measurements are out of specifications, inspect for the following conditions: 

z

Sagging front suspension Refer to Torsion Bar Replacement in Front Suspension.  

z

Sagging rear coil springs Refer to COIL SPRING REPLACEMENT .  

z

Proper air suspension operation.  

z

Worn rear suspension components.  

z

Improper tire inflation.  

z

Improper weight distribution.  

z

Collision damage.  

VEHICLE LEADS/PULLS 

Definition: At a constant highway speed on a typical straight road, lead/pull is the amount of effort required at 
the steering wheel to maintain the vehicle's straight path. 

 

2004 Hummer H2 

2003-04 SUSPENSION General Diagnosis - H2

  

1. Did you review the General Description and perform the necessary inspections? If yes, go to next step. If 

no, go to SYMPTOMS - SUSPENSION GENERAL DIAGNOSIS .  

2. Road test the vehicle in order to verify the complaint. Does the vehicle operate normally? If yes, system is 

okay. If no, go to next step.  

3. Inspect the tire/wheel assemblies for: 

z

Correct tire pressure.  

z

Correct tire size.  

Did you find and correct the condition? If yes, go to step 9 . If no, go to next step.  

4. Perform the Radial Tire Lead/Pull Correction. Did you find and correct the condition? If yes, go to step 

9 . If no, go to next step.  

5. Inspect and correct/adjust the suspension and steering systems for the following conditions: 

z

Vehicle trim height. See TRIM HEIGHT INSPECTION PROCEDURE  

z

Excessively worn, loose, or damaged components.  

Did you find and correct the condition? If yes, go to step 9 . If no, go to next step.  

6. Inspect the brake system for brake drag. With the vehicle suspended on a hoist, brake drag can be 

identified by rotating each wheel several times and observing whether more force is need to rotate the left 
wheel or the right wheel. Did you find and correct the condition? If yes, go to step 9 . If no, go to next 
step.  

7. Inspect the wheel alignment and adjust as necessary. Refer to SPECIFICATIONS . Did you correct the 

condition? If yes, go to step 9 . If no, go to next step.  

8. Inspect the steering gear for unequal effort. The vehicle must be suspended on a hoist, the engine running, 

and the transmission in park or neutral. Grasp the tire assembly and instructionly simulate a turn from the left 
of center and the right of center observing whether more force is needed to turn to the left or to the right. 
If this condition exists replace the steering gear. Did you correct the condition? If yes, system is okay. If 
no, go to step 3 .  

9. Operate the vehicle in order to verify the repair. Did you correct the condition? If yes, system is okay. If 

no, go to step 3 .  

WHEEL BEARING DIAGNOSIS 

1. Did you review the General Description and perform the necessary inspections? If yes, go to next step. If 

no, go to SYMPTOMS - SUSPENSION GENERAL DIAGNOSIS .  

2. Road test the vehicle in order to verify the customer's complaint. Does the vehicle operate normally? If 

yes, system is okay. If no, go to next step.  

3. Raise and support the vehicle. Inspect for tire or wheel damage. Did you find and correct the condition? If 

yes, go to step 7 . If no, go to next step.  

4. Install the J-39570 chassis ear. See SPECIAL TOOLS . Road test the vehicle to verify the location of 

the wheel bearing noise. Did you locate the source of the wheel bearing noise? If yes, go to step 6 . If no, 
go to next step.  

5.  

NOTE:

If you are inspecting the FRONT wheel bearing/hub, support the front of 

 

2004 Hummer H2 

2003-04 SUSPENSION General Diagnosis - H2

  

Raise and support the vehicle. Remove the wheel and tire. Mount and secure the J-8001 to the steering 
knuckle. Firmly push the hub flange towards the vehicle. Ensure that the J-8001 contacts the vertical 
surface of the hub flange as close as possible to the center of the flange. Firmly pull the hub flange away 
from the vehicle. Inspect the total movement indicated by the J-8001. Is the measurement greater than 
0.051 mm (0.002 in)? If yes, go to next step. If no, system is okay.  

6. Replace the wheel bearing. Refer to FRONT SUSPENSION. After repairs, go to next step.  

7. Road test the vehicle to verify the repair. Does the vehicle operate normally? If yes, system is okay. If no, 

go to step 3 .  

SPECIAL TOOLS 

the vehicle by the lower control arms in order to load the lower ball joint. 

 

2004 Hummer H2 

2003-04 SUSPENSION General Diagnosis - H2