Hummer H3. Manual — part 1322

Fig. 8: Identifying Brake Caliper/Pad Inspection Areas
Courtesy of GENERAL MOTORS CORP.

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

visually inspect the caliper piston dust boot (2) 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.

3. While the brake system is at rest (4), observe the position of the caliper piston (1) in relation

to the caliper housing.

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

operation of the hydraulic brake caliper.

1. Observe the caliper piston (1) for unrestricted and even movement during each apply

of the brake system (5).

2. Observe the caliper piston (1) for an unrestricted and even return motion during each

release of the brake system (6).

5. If the caliper piston (1) did not exhibit unrestricted and even movement during brake system

apply and/or release, the piston square seal (3) may be worn or damaged and the caliper
may require overhaul or replacement.

BRAKE PIPE AND HOSE INSPECTION

1. Visually inspect all of the brake pipes for the following conditions:

Kinks, improper routing, missing or damaged retainers

Leaking fittings, excessive corrosion

CAUTION: Refer to Brake Fluid Irritant Caution .

NOTE:

Refer to Brake Fluid Effects on Paint and Electrical
Components Notice .

CAUTION: Refer to Brake Fluid Irritant Caution .

NOTE:

Refer to Brake Fluid Effects on Paint and Electrical Components
Notice .

2007 Hummer H3

2007 BRAKES Hydraulic Brakes - H3

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

pipes, require replacement.

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.

Fig. 9: Identifying Flexible Brake Hose Failure Conditions
Courtesy of GENERAL MOTORS CORP.

4. Visually inspect all of the flexible brake hoses for the following conditions:

Kinks (1), improper routing, twists, chafing, missing or damaged retainers

Leaking connections, cracking, dry-rot, blisters, 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.

6. Squeeze the flexible brake hoses with firm finger pressure to check for soft spots (2),

2007 Hummer H3

2007 BRAKES Hydraulic Brakes - H3

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 (2), then the identified

flexible brake hose or hoses require replacement.

BRAKE PEDAL PUSHROD INSPECTION

Fig. 10: View Of Brake Pedal Push Rod And Clevis
Courtesy of GENERAL MOTORS CORP.

1. Disconnect the brake pedal pushrod (1) from the brake pedal.

2. Inspect the brake pedal pushrod clevis (2), if equipped, for cracks and/or excessive wear.

3. Reposition the pedal pushrod boot (3) toward the front of the vehicle to expose as much of

the pedal pushrod (1) as possible.

4. Inspect the brake pedal pushrod (1) for straightness.

2007 Hummer H3

2007 BRAKES Hydraulic Brakes - H3

5. If the brake pedal pushrod clevis (2) exhibited cracks and/or excessive wear, then the master

cylinder requires replacement.

6. If the brake pedal pushrod (1) is not straight, then the master cylinder requires replacement.

7. Return the pedal pushrod boot (3) to its original position on the pedal pushrod (1).

8. Connect the brake pedal pushrod (1) to the brake pedal.

REPAIR INSTRUCTIONS

MASTER CYLINDER RESERVOIR FILLING (WITHOUT RPO BRM)

1. Visually inspect the brake fluid level through the brake master cylinder reservoir.

2. If the brake fluid level is at or below the half-full point during routine fluid checks, the

brake system should be inspected for wear and possible brake fluid leaks.

3. If the brake fluid level is at or below the half-full point during routine fluid checks and an

inspection of the brake system did not reveal wear or brake fluid leaks, the brake fluid may
be topped-off up to the maximum-fill level.

4. If brake system service was just completed, the brake fluid may be topped-off up to the

maximum-fill level.

CAUTION: Refer to Brake Fluid Irritant Caution .

NOTE:

When adding fluid to the brake master cylinder reservoir, use only
Delco Supreme 11®, GM P/N 12377967 (Canadian P/N 992667) or
equivalent DOT-3 brake fluid from a clean, sealed brake fluid
container. The use of any type of fluid other than the recommended
type of brake fluid, may cause contamination which could result in
damage to the internal rubber seals and/or rubber linings of
hydraulic brake system components.

NOTE:

Refer to Brake Fluid Effects on Paint and Electrical Components
Notice .

IMPORTANT: Before checking the HB-Ci Master Cylinder Reservoir brake fluid

level, the accumulator fluid reserve must be drained. Depress and
release the brake pedal 20 times with the ignition OFF to deplete
accumulator reserve. Failure to drain the accumulator prior to
checking the brake fluid level can lead to system over filling.

2007 Hummer H3

2007 BRAKES Hydraulic Brakes - H3