Hummer H2. Manual — part 842

1. Verify that the automatic adjuster lock-out pin has been removed.

2. Fully apply and release the park brake pedal 3 times.

DESCRIPTION AND OPERATION

PARK BRAKE SYSTEM DESCRIPTION AND OPERATION

System Component Description

The park brake system consists of the following:

Park Brake Pedal Assembly

Receives and transfers park brake system apply input force from driver to park brake cable system.

Park Brake Release Handle Assembly

Releases applied park brake system when pulled.

Park Brake Cables

Transfers input force received from park brake pedal, through park brake cable equalizer, to park brake
apply lever.

Park Brake Cable Equalizer

Evenly distributes input force to both the left and right park brake units.
Threaded park brake cable equalizers are also used to remove slack in park brake cables.

Park Brake Apply Lever

Multiplies and transfers input force to park brake actuator.

Park Brake Actuator/Adjuster

Uses multiplied input force from apply lever to expand park brake shoe toward the friction surface of the
drum-in-hat portion of the rear brake rotor.
Threaded park brake actuators are also used to control clearance between the park brake shoe and the
friction surface of the drum-in-hat portion of the rear brake rotor.

Park Brake Shoe

Applies mechanical output force from park brake actuator to friction surface of the drum-in-hat portion of

IMPORTANT: Before you adjust the park brake, verify that the park brake shoes are adjusted

to provide a clearance of 0.6604 mm (0.026 in).

2004 Hummer H2

2004 BRAKES Park Brake - Hummer H2

the rear brake rotor.

System Operation

Park brake apply input force is received by the park brake pedal assembly being depressed, transferred and
evenly distributed, through the park brake cables and the park brake cable equalizer, to the left and right park
brake apply levers. The park brake apply levers multiply and transfer the apply input force to the park brake
actuators which expand the park brake shoe toward the friction surface of the drum-in-hat portion of the rear
brake rotor in order to prevent the rotation of the rear tire and wheel assemblies. The park brake release handle
assembly releases an applied park brake system when it is pulled rearward.

SPECIAL TOOLS AND EQUIPMENT

SPECIAL TOOLS

Special Tools

Illustration

Tool Number/Description

J 21177-A

Drum-to-Brake Shoe Clearance Gauge

2004 Hummer H2

2004 BRAKES Park Brake - Hummer H2

2003-04 DRIVE AXLES

Axle Shafts - Front - Hummer H2

IDENTIFICATION

MODEL IDENTIFICATION

DESCRIPTION & OPERATION

AXLE SHAFTS

Front axle shafts are flexible assemblies which consist of the following components:

z

Front constant velocity outer joint.

z

Front tri-pot inner joint.

z

The front axle shaft connects the tri-pot joint and the constant velocity joint.

z

The tri-pot joint is completely flexible, and moves with an in and out motion.

z

The constant velocity joint is flexible but can not move in and out.

The axle shaft is a balanced shaft that transmits rotational force from the front differential to the front wheels
when the transfer case is engaged. The axle shaft is mounted to the front differential by bolting the flange of the
axle shaft to the flange on the inner output shaft of the front differential. The other end of the axle shaft is
splined to fit into and drive the hub assembly when the transfer case is engaged. The tri-pot joint and constant
velocity joint on the axle shaft allows the shaft to be flexible to move with the suspension travel of the vehicle.

COMPONENT LOCATIONS

To identify and locate axle shaft components, see Fig. 1 for views of axle shafts.

Body Code

(1)

Model

"N"

Hummer H2

(1)

Vehicle body code is 5th character of VIN.

2004 Hummer H2

2003-04 DRIVE AXLES Axle Shafts - Front - Hummer H2

2004 Hummer H2

2003-04 DRIVE AXLES Axle Shafts - Front - Hummer H2

Fig. 1: Exploded View Of Axle Shaft Assembly
Courtesy of GENERAL MOTORS CORP.

TROUBLE SHOOTING

DIAGNOSTIC STARTING POINT - AXLE SHAFTS

2004 Hummer H2

2003-04 DRIVE AXLES Axle Shafts - Front - Hummer H2