Hummer H2. Manual - part 783

Fig. 8: Inspecting Disc Brake Mounting & Hardware 
Courtesy of GENERAL MOTORS CORP. 

Inspection (Rear) 

1. Remove the disc brake caliper from the caliper mounting bracket. See BRAKE CALIPER under 

REMOVAL & INSTALLATION.  

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

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

mounting tabs, looseness at the caliper mounting bracket and looseness at the disc brake pads. See Fig. 8 . 

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

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

mounting hardware without binding.  

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

bracket. See BRAKE CALIPER under REMOVAL & INSTALLATION.  

HYDRAULIC BRAKE ASSIST SYSTEM NOISE INSPECTION 

1. Install the Brake Pedal Effort Gage (J-28662) to the brake pedal.  

2. Start the engine and allow it to idle. Ensure that the wheels are directed straight ahead.  

3. Apply and maintain the brakes with 25 Lbs. (111 N) of force to the brake pedal, as indicated on the brake 

pedal effort gage. Observe for noises.  

4. Quickly release the brakes. Observe for noises.  

5. If chatter and/or a vibration of the brake pedal was apparent during the brake system apply of 25 Lbs. 

(111 N) of force, the power steering drive belt is probably slipping and would require replacement.  

6. If any significant noise was apparent during the quick release of the brakes following the brake system 

apply of 25 Lbs. (111 N) of force, there is likely a restriction in the hydraulic brake booster power 
steering return hose and it would require replacement. 

7. Apply the brakes with 40 Lbs. (178 N) of force to the brake pedal, as indicated on the brake pedal effort 

gage, then gradually increase pedal effort up to 100 Lbs. (445 N) of force for not more than 5 seconds at a 
time. Observe for noises.  

8. Quickly release the brakes. Observe for noises.  

9. If a hiss noise was apparent and increased during the brake system increasing apply of 40-100 Lbs. (178-

445 N) of force, the hydraulic brake booster assist system is operating normally from an audible 
standpoint.  

10. If a clunk, chatter, and/or clicking noise was apparent during the quick release of the brakes following the 

brake system increasing apply of 40-100 Lbs. (178-445 N) of force, the hydraulic brake booster assist 
system is operating normally from an audible standpoint.  

HYDRAULIC BRAKE COMPONENT OPERATION VISUAL INSPECTION 

CAUTION: DO NOT apply 100 Lbs. (445 N) of force or more to the brake system 

pedal for more than 5 seconds at a time. 

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. With the tire and wheel assemblies removed and the brake rotors retained by wheel lug nuts, visually 

inspect the caliper piston dust boot sealing area to ensure that there are no brake fluid leaks.  

2. If any evidence of a brake fluid leak is present, the brake caliper requires overhaul or replacement. 

z

For overhaul, see BRAKE CALIPER under OVERHAUL.  

z

For replacement, see BRAKE CALIPER under REMOVAL & INSTALLATION.  

3. While the brake system is at rest, observe the position of the caliper piston in relation to the caliper 

housing. See Fig. 9 .  

4. Have an assistant apply and release the brake pedal several times while you observe the operation of the 

hydraulic brake caliper. 

z

Observe the caliper piston for unrestricted and even movement during each apply of the brake 
system.  

z

Observe the caliper piston for an unrestricted and even return motion during each release of the 
brake system.  

5. If the caliper piston did not exhibit unrestricted and even movement during brake system apply and/or 

release, the piston square seal may be worn or damaged and the caliper may require overhaul or 
replacement: 

z

For overhaul, see BRAKE CALIPER under OVERHAUL.  

z

For replacement, see BRAKE CALIPER under REMOVAL & INSTALLATION. 

clean shop cloth to wipe away the fluid. 

 

2004 Hummer H2 

2003-04 BRAKES Disc - Hummer

  

Fig. 9: Identifying Hydraulic Brake Component Operation 
Courtesy of GENERAL MOTORS CORP. 

PARK BRAKE SHOE INSPECTION 

 

2004 Hummer H2 

2003-04 BRAKES Disc - Hummer