Hummer H1 (2002+). Manual - part 102

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Wheels and Tires/Central Tire Inflation System (CTIS) 6-23

05745159

Figure 6-39: Upper Ball Joint Wear Check

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

Check lower ball joints: Support lower control arm with a
jack or stand to unload lower ball joint. Place bar between
lower arm at ball joint and geared hub and measure
vertical play obtained by moving pry bar down

(Figure 6-40). Maximum play should not

exceed 1/8"

(3.5 mm). Replace ball joint if end play exceeds the limit.

Check steering center link, idler arm and tie rod ends for
wear or damage (Figure 6-41). Replace parts as needed
before proceeding.

Check idler and 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 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. Center link

deformation will cause excessive front wheel toe. If center
link deformation is suspected, remove the suspect center
link from the vehicle and place it on a level surface 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

Figure 6-40: Lower Ball Joint Wear Check

PRYBAR CONTACT POINT

MEASURE

MOVEMENT

HERE

PRYBAR

MEASURE

MOVEMENT

HERE

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Wheels and Tires/Central Tire Inflation System (CTIS)

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Figure 6-41: Suspension Component Identification

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) 6-25

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CHECKING WHEEL ALIGNMENT

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

Place front wheels in straight ahead position on turntables.

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

Measure and record caster, camber, toe-in, and toe-out.
Refer to alignment specifications (Figure 6-42).

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

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).

SERVICE WHEEL ALIGNMENT

SUSPENSIO

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)

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Wheels and Tires/Central Tire Inflation System (CTIS)

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Figure 6-42: Wheel Alignment Information

WHEEL ALIGNMENT CORRECTION

Alignment adjustments should be performed one at a time and
in sequence to avoid errors. Recommended adjustment se-
quence is:

caster

camber

front toe setting

rear toe setting

steering stops (See Section 8)

Leave the vehicle on the alignment rack for each of the adjust-
ment procedures. This way, angle correction can be monitored
continuously during actual adjustment.

Caster Adjustment

Caster adjustment applies to the front wheels only. It is con-
trolled by turning the pivot bolts and eccentric washers on the
upper control arm brackets (Figure 6-43). A positive caster an-
gle is required on all Hummer vehicles.

Preferred caster angle is +2.5 to +3.5 degrees. Maximum al-
lowable side-to-side variation is 0.5 degree.

Support the vehicle weight with the tires on the turntables.

Loosen upper control arm pivot bolt locknuts by holding
the bolt head and turning the locknut to allow movement
of the bolts (Figure 6-43).

Pry the upper control arm brackets open to allow freedom
of movement of the control arm bushings. The edges of
the control arm bushings are serrated and will be difficult
to move if the brackets are not pried open.

Adjust caster angle by turning the eccentrics on the upper
control arm brackets in opposite directions (Figure 6-43).

• Preferred caster is +2.5 to +3.5 degrees and left-right

variation must not exceed 0.5 degree.

• Turning the front eccentric outward and the rear eccen-

tric inward increases positive caster while turning the
front eccentric inward and the rear outward decreases it.

• Shims are available in 0.060 inch and 0.120 inch

(1.5 and 3.0 mm) thicknesses for use behind the control
arm mount brackets if the proper angles cannot be
achieved with the use of the eccentrics alone. This
would be an unusual situation and the vehicle should be
inspected thoroughly for bent or worn parts before in-
stalling shims.

Tighten control arm pivot bolt nuts to 260 lb-ft (359 N•m)
torque.

Verify correct caster angle at both front wheels. Be sure
side-to-side caster variation does not exceed 0.5 degree.

Leave vehicle on rack for camber and toe adjustments.

FRONT

TOE-IN (+)

(POSITIVE SENSE)

TOE-OUT (-)

(NEGATIVE SENSE)

REAR

NEGATIVE (-)

CAMBER

POSITIVE (+)

CAMBER

POSITIVE (+)

CASTER

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