Hummer H2. Manual — part 782

1. Visually inspect all of the brake pipes for kinks, improper routing, missing or damaged retainers, leaking

fittings and excessive corrosion.

2. If any of the brake pipes exhibited any of the conditions listed, then the identified pipe, or pipes, require

replacement. See BRAKE PIPE under REMOVAL & INSTALLATION.

3. Ensure that the vehicle axles are properly supported at ride height in order to maintain the proper

relationship of the flexible brake hoses to the chassis.

4. Visually inspect all of the flexible brake hoses for kinks, improper routing, twists, chafing, missing or

damaged retainers, leaking connections, cracking, dry-rot, blisters or bulges.

5. If any of the flexible brake hoses exhibited any of the conditions listed, then the identified flexible brake

hose, or hoses require replacement. See BRAKE HOSE under REMOVAL & INSTALLATION.

6. Squeeze the flexible brake hoses with firm finger pressure to check for soft spots, indicating an internal

restriction. Check the entire length of each flexible brake hose.

7. If any of the flexible brake hoses were found to have soft spots, then the identified flexible brake hose, or

hoses require replacement. See BRAKE HOSE under REMOVAL & INSTALLATION.

BRAKE PEDAL TRAVEL MEASUREMENT & INSPECTION

1. With the ignition OFF and the brakes cool, apply the brakes 3-5 times, or until the brake pedal becomes

firm, in order to deplete the brake booster power reserve.

2. Install the Brake Pedal Effort Gauge (J-28662) to the brake pedal.

3. Measure and record the distance from the brake pedal to the rim of the steering wheel; note the points of

measurement. See Fig. 7 .

4. Apply and maintain the brakes with 100 Lbs. (445 N) of force to the brake pedal, as indicated on the

brake pedal effort gauge.

5. While maintaining 100 Lbs. (445 N) of force to the brake pedal, measure and record the distance from the

same point on the brake pedal to the same point on the rim of the steering wheel.

6. Release the brakes and repeat steps 4 and 5 to obtain a second measurement. After obtaining a second

measurement, proceed to next step.

7. Average the first and second measurements recorded during the 2 applies of the brakes.

8. Subtract the initial measurement, un-applied, from the averaged, applied measurement to obtain the brake

pedal travel distance. For hydraulic assist equipped, maximum brake pedal travel (measured with the
ignition OFF, brake booster power assist depleted, and the brakes cool) is 3.54" (90 mm).

thoroughly with water. In case of skin contact, wash with soap and water.
If ingested, consult a physician immediately.

CAUTION: Avoid spilling brake fluid onto painted surfaces, electrical connections,

wiring, or cables. Brake fluid will damage painted surfaces and cause
corrosion to electrical components. If any brake fluid comes in contact
with painted surfaces, immediately flush the area with water. If any brake
fluid comes in contact with electrical connections, wiring, or cables, use a
clean shop cloth to wipe away the fluid.

2004 Hummer H2

2003-04 BRAKES Disc - Hummer

Fig. 7: Measuring Brake Pedal Travel
Courtesy of GENERAL MOTORS CORP.

BRAKE SYSTEM EXTERNAL LEAK INSPECTION

WARNING:

Brake fluid may irritate eyes and skin. In case of eye contact, rinse
thoroughly with water. In case of skin contact, wash with soap and water.
If ingested, consult a physician immediately.

CAUTION: Avoid spilling brake fluid onto painted surfaces, electrical connections,

wiring, or cables. Brake fluid will damage painted surfaces and cause
corrosion to electrical components. If any brake fluid comes in contact
with painted surfaces, immediately flush the area with water. If any brake
fluid comes in contact with electrical connections, wiring, or cables, use a

2004 Hummer H2

2003-04 BRAKES Disc - Hummer

1. In order to inspect for external brake fluid leaks, first check the fluid level in the master cylinder. While a

slight brake fluid level drop can be considered a normal condition due to brake lining wear, a very low
level may indicate a brake fluid leak in the hydraulic system.

2. If the fluid level is abnormally low, adjust the brake fluid level. See MASTER CYLINDER

RESERVOIR FILLING under BLEEDING BRAKE SYSTEM.

3. Start the engine and allow it to idle.

4. Apply constant, moderate foot pressure to the brake pedal. If the brake pedal gradually falls away while

under foot pressure, there may be a brake fluid leak.

5. Turn OFF the ignition.

6. Visually inspect the following brake system components for brake fluid leaks, excessive corrosion, and

damage. Give particular attention to all brake pipe and flexible hose connections to ensure that there are
not any slight brake fluid leaks, even though the brake pedal may feel firm and hold steady:

z

Master cylinder brake pipe fittings.

z

All brake pipe connections.

z

Brake pipes.

z

Brake hoses and connections.

z

Brake calipers and/or wheel cylinders (if equipped).

7. While slight dampness around the master cylinder reservoir can be considered acceptable, brake fluid

leaking from any of the brake system components requires immediate attention. If any of these
components exhibit signs of brake fluid leakage, repair or replace those components. After the repair or
replacement, reinspect the hydraulic brake system to assure proper function.

DISC BRAKE MOUNTING & HARDWARE

Inspection (Front)

1. Inspect the fluid level in the brake master cylinder reservoir.

2. If the brake fluid level is midway between the maximum-full point and the minimum allowable level then

no brake fluid needs to be removed from the reservoir before proceeding.

3. If the brake fluid level is higher than midway between the maximum-full point and the minimum

allowable level then remove brake fluid to the midway point before proceeding.

4. Raise and support the vehicle.

clean shop cloth to wipe away the fluid.

WARNING:

Avoid grinding brake linings, sanding brake linings or cleaning wheel
brake parts with a dry brush or with compressed air, when servicing
wheel brake parts. Some models or aftermarket brake parts may contain
asbestos fibers which can become airborne in dust. Breathing dust with
asbestos fibers may cause serious bodily harm. Use a water-dampened
cloth in order to remove any dust on brake parts. Equipment is available
commercially in order to perform this washing function. These wet
methods prevent fibers from becoming airborne.

2004 Hummer H2

2003-04 BRAKES Disc - Hummer

5. Remove the tire and wheel assembly.

6. Grasp the brake caliper housing and try to move the brake caliper housing up/down and forward/reverse

in relation to the brake caliper mounting bracket. If excessive looseness is observed the brake caliper
bracket bushings and/or the brake caliper mounting bolts may need to be replaced.

7. Compress the front caliper pistons:

A. Install a large C-clamp over the top of the caliper housing and against the back of the outboard pad.

B. Slowly tighten the C-clamp until the pistons are pushed completely into the caliper bores.

C. Remove the C-clamp from the caliper.

8. With the pistons compressed into the caliper bores, grasp the brake caliper housing and slide it back and

forth on the brake caliper mounting bolts. Check for smooth operation. If the brake caliper housing slide
force is high or the brake caliper housing does not slide smoothly, inspect the brake caliper mounting
bolts and/or the brake caliper mounting bracket bushings for wear or damage. If wear or damage
conditions are found, replacement of the brake caliper mounting bolts and/or the brake caliper mounting
bracket bushings is necessary.

9. Remove the brake caliper mounting bolts from the brake caliper mounting bracket and support the brake

caliper using heavy mechanics wire. DO NOT remove the hydraulic brake hose from the caliper. See
BRAKE CALIPER under REMOVAL & INSTALLATION.

10. Remove the disc brake pads from the brake caliper mounting bracket.

11. Inspect the disc brake pad mounting hardware for missing mounting hardware, excessive corrosion, bent

mounting tabs, looseness at the brake caliper mounting bracket, looseness at the disc brake pads, or
excessive contaminants in the brake caliper mounting bracket surface and threads. See Fig. 8 .

12. If any of the conditions listed are found, the disc brake pad mounting hardware requires replacement.

13. Ensure the disc brake pads are held firmly in place on the brake caliper mounting bracket, yet slide easily

on the mounting hardware without binding.

14. Inspect the caliper bolts for binding, seizing, looseness in the brake caliper mounting bracket, bent or

damaged brake caliper mounting bolts, cracked or torn boots, missing boots, or a bent or damaged brake
caliper mounting bracket.

15. If any of the conditions listed are found then the brake caliper mounting hardware requires replacement.

16. Install the disc brake pads to the brake caliper mounting bracket.

17. Install the disc brake caliper to the brake caliper mounting bracket. See BRAKE CALIPER under

REMOVAL & INSTALLATION.

2004 Hummer H2

2003-04 BRAKES Disc - Hummer