Hummer H1 (2006+). Manual - part 220

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Wheels and Tires/Central Tire Inflation System (CTIS)

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NOTE: If the vehicle was previously lifted off the ground for other service, center the steering wheel, roll the vehicle forward and
back to settle the suspension and relieve the tension on the ball joints before beginning checking procedure.

Check the upper ball joints: With the vehicle on the ground (being careful not to damage the boot), place the tip of a pry bar
between the steering knuckle and the ball joint boot (Figure 6-37). With the shank of the pry bar contacting the upper control
arm as shown, pry upward and note the movement of the ball joint against a ruler. Be careful to measure only the ball joint
movement and not the flex of the control arm resulting from prying against it. Any upper ball joint with more than 1/16” (1.6
mm) movement should be replaced.

Check the geared hubs for spindle end play or side-to-side movement by grasping the edge of the tire and attempting to move
the tire up and down.

NOTE: If any spindle movement is apparent, adjust the spindle bearings.

Figure 6-36: Suspension Inspection Components

CONTROL ARM

UPPER

GEARED HUB

LOWER

TIE ROD

CONTROL ARM

BUSHING

BALL JOINT

CONTROL

ARM

BUSHING

STABILIZER

BAR

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Wheels and Tires/Central Tire Inflation System (CTIS) 6-31

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Figure 6-37: Upper Ball Joint Wear Check

Inspect the control arm bushings for wear or damage. Replace the bushings if necessary.

Check the lower ball joints: Support the lower control arm with a jack or stand to unload the lower ball joint. Place the pry bar
between the lower arm at the ball joint and geared hub and measure the vertical play obtained by moving the pry bar down
(Figure 6-38). Maximum play should not exceed 1/8" (3.5 mm). Replace the ball joint if end play exceeds the limit.

Check the steering center link, idler arm and tie rod ends for wear or damage (Figure 6-39). Replace the parts as needed before
proceeding.

Check the idler and the steering arms by pulling the center link vertically up and down with a 50 lb. spring scale. Maximum
allowable movement is 1/4 inch (7 mm), 1/8 inch (3.5 mm) up or down, when pulled within 2 inch (51 mm) of ball stud.

10. Lower the vehicle.

11. Check the tie rod end wear by trying to move the tie rod vertically and horizontally. Replace the tie rod end(s) if any

movement is apparent.

12. Inspect the center link for distortion. The center link deformation will cause excessive front wheel toe. If the center link

deformation is suspected, remove the suspect center link from the vehicle and place it on a level surface or next to a new center
link. Carefully compare the two parts, checking for distortion and tapered hole wear. Replace the suspect center link if tapered
holes are worn or if the center link is distorted.

13. Check the center link and stabilizer bar for cracks or distortion. Replace if necessary.

14. Inspect the stabilizer bar bushings for excessive wear and/or distortion. Replace if necessary.

15. Check the steering gear for looseness-to-frame, proper operation, and excessive leakage. Repair if necessary.

7-S09-026.1

PRY BAR CONTACT POINT

MEASURE

MOVEMENT

HERE

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Wheels and Tires/Central Tire Inflation System (CTIS)

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Figure 6-38: Lower Ball Joint Wear Check

Figure 6-39: Suspension Component Identification

CHECKING WHEEL ALIGNMENT

Move the vehicle onto the alignment rack and position the front tires on the alignment rack turntables.

Place the front wheels in the straight ahead position on the turntables.

Install the alignment measuring equipment on the vehicle wheels. Follow the manufacturers instructions to avoid incorrect
measurements.

Measure and record the caster, camber, toe-in, and the toe-out. Refer to the alignment specifications (Figure 6-40).

If the alignment angles are within specified limits, move the vehicle from the rack. However, if the angles are incorrect, leave
the vehicle on the alignment rack and proceed to the Wheel Alignment Correction.

PRY BAR

MEASURE

MOVEMENT

HERE

PITMAN

ARM

CENTER

LINK

TIE ROD

IDLER

ARM

TIE ROD

HALFSHAFT

TIE ROD END

GEARED

HUB

ADJUSTING

SLEEVE

STABILIZER

BAR

SPRING

SCALE

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Wheels and Tires/Central Tire Inflation System (CTIS) 6-33

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To measure in inches, 0.1 degree = 1/16", 0.19 degrees = 1/8", 0.25 degrees = 5/32

(A) Left and right side to be equal within 0.5 degrees.

(B) Left and right side to be equal within 1.0 degrees.

(C) Toe-in (Positive sense) left and right sides to be set separately and evenly per wheel. Steering wheel must be held in a center
position within + or - 5 degrees

(D) Toe-out (negative sense) left and right side to be set separately and evenly per wheel

(E) Left and right side toe settings to be equal within 0.10 degree

NOTE: Alignment settings should be checked and adjusted on a rack that allows all four wheels/tires to support vehicle weight.

Set wheel alignment while the vehicle is in its normally loaded condition.

Vehicles which are consistently operated with heavy on-board loads should have alignment adjusted with the vehicle under heavy
on-board load.

Ride height should be checked and corrected if necessary and the hood should be closed while taking measurements (See “Suspen-
sion Height Measurement” Section 9).

Figure 6-40: Wheel Alignment Information

SERVICE WHEEL ALIGNMENT

SUSPENSION

POSITION

TIRE

PRESSURE

(PSI)

SERVICE CHECKING

SERVICE SETTING

CASTER

(DEGREES)

CAMBER

(DEGREES)

TOE-TOTAL

(DEGREES)

CASTER

(DEGREES)

CAMBER

(DEGREES)

TOE-TOTAL

(DEGREES)

FRONT

REAR

+1.5 to +4.0
(B)

-0.2 to +1.75
(B)

0 to +0.25
(C)

-0.25 to 0
(D)

+2.5 to +3.5
(A)

+0 to +0.50
(A)

+.25 to
+0.75 (A)

0 to +0.19
(C&E)

-0.19 to 0
(D&E)

FRONT

TOE-IN (+)

(POSITIVE SENSE)

TOE-OUT (-)

(NEGATIVE SENSE)

REAR

NEGATIVE (-)

CAMBER

POSITIVE (+)

CAMBER

POSITIVE (+)

CASTER

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