Hummer H2. Manual — part 785

Inspect for aftermarket devices which could affect the operation of the park brake system. Inspect the easily
accessible or visible system components for obvious damage or conditions which could cause the symptom.

Symptom List

z

See BRAKE WARNING INDICATOR ALWAYS ON under SYMPTOM TESTS.

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See BRAKE WARNING INDICATOR INOPERATIVE under SYMPTOM TESTS.

z

See BRAKE PULSATION under SYMPTOM TESTS.

z

See BRAKE SYSTEM NOISE under SYMPTOM TESTS.

z

See BRAKING ACTION UNEVEN (PULLS TO ONE SIDE) under SYMPTOM TESTS.

z

See BRAKING ACTION UNEVEN (FRONT TO REAR) under SYMPTOM TESTS.

z

See BRAKE PEDAL EXCESSIVE TRAVEL under SYMPTOM TESTS.

z

See BRAKE PEDAL EXCESSIVE EFFORT under SYMPTOM TESTS.

z

See BRAKES DRAG under SYMPTOM TESTS.

z

See BRAKE SYSTEM SLOW RELEASE under SYMPTOM TESTS.

z

See BRAKE FLUID LOSS under SYMPTOM TESTS.

CHECKING AFTERMARKET ACCESSORIES

DO NOT connect aftermarket accessories into the SIR circuits (all such circuits are indicated on circuit
diagrams with the SIR symbol) and the OBD II circuits (all such circuits are indicated on circuit diagrams with
the OBD II symbol).

Always check for aftermarket accessories (non-OEM) as the first step in diagnosing electrical problems. If the
vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the
problems.

Possible causes of vehicle problems related to aftermarket accessories include:

NOTE:

Refer to a symptom diagnostic procedure from the following list in order to
diagnose the symptom.

WARNING:

When you are performing service on or near the SIR components or the
SIR wiring, you must disable the SIR system. See AIR BAG RESTRAINT
SYSTEMS under RESTRAINTS. Failure to follow the correct procedure
could cause air bag deployment, personal injury, or unnecessary SIR
system repairs.

NOTE:

The OBD II symbol is used on the circuit diagrams in order to alert the
technician that the circuit is essential for proper OBD II emission control circuit
operation. Any circuit which fails and causes the Malfunction Indicator light
(MIL) to turn ON, or causes emissions-related component damage, is identified
as an OBD II circuit.

2004 Hummer H2

2003-04 BRAKES Disc - Hummer

z

Power feeds connected to points other than the battery.

z

Antenna location.

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Transceiver wiring located too close to vehicle electronic modules or wiring.

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Poor shielding or poor connectors on antenna feed line.

z

Check for recent service bulletins detailing installation guidelines for aftermarket accessories.

DISC BRAKE SYSTEM DIAGNOSIS

1. If you sent here from a brake symptom test, go to step 2 . If you were not sent her from a brake symptom,

see HYDRAULIC BRAKE SYSTEM under DIAGNOSTIC STARTING POINTS.

2. Visually inspect the disc brake pads for the following conditions:

z

Lining thickness below specifications.

z

Uneven and/or abnormal wear, edge-to-edge and/or side-to-side.

z

Looseness or damage, including pad hardware.

z

Evidence of contamination from an external substance.

If any of the conditions were found and indicated a concern with any of the front and/or rear disc brake
pads, go to step 3 . If any of the conditions were not found and did not cause any concern, go to step 12 .

3. If any of the front and/or rear disc brake pads are contaminated, go to step 8 . If any of the front and/or

rear disc brake pads are not contaminated, go to step 4 .

4. If any of the front and/or rear disc brake pads are worn unevenly, go to step 7 . If any of the front and/or

rear disc brake pads are not worn unevenly, go to step 5 .

5. If any of the front and/or rear disc brake pads and/or pad hardware are loose or damaged, go to step 7 . If

any of the front and/or rear disc brake pads and/or pad hardware are not loose or damaged, go to step 6 .

6.

z

Remove and inspect the worn disc brake pads for glazing, looseness, heat spots or damage.

z

Replace the worn disc brake pads as a complete axle set. See BRAKE PADS under REMOVAL &
INSTALLATION.

If the inspection and replacement was completed, go to step 12 .

7.

A. Remove the front and/or rear disc brake calipers, as appropriate, from the mounting brackets and

support the calipers. See BRAKE CALIPER under REMOVAL & INSTALLATION.

B. Inspect the disc brake caliper mounting bracket and the mounting/sliding hardware for the

CAUTION: DO NOT disconnect the hydraulic brake flex hoses from the calipers.

NOTE:

Support the brake caliper with heavy mechanic's wire, or equivalent,
whenever it is separated from its mount and the hydraulic flexible brake
hose is still connected. Failure to support the caliper in this manner will
cause the flexible brake hose to bear the weight of the caliper, which may
cause damage to the brake hose and in turn may cause a brake fluid leak.

2004 Hummer H2

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following conditions:

z

Binding or seized hardware.

z

Worn, damaged or missing hardware components.

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Loose, bent, cracked, or damaged caliper mounting bracket.

See DISC BRAKE MOUNTING & HARDWARE under ADJUSTMENTS & INSPECTION.

C. Replace components as required. Refer to the following procedures as required:

z

Replace the front and/or rear brake caliper bracket. See BRAKE CALIPER BRACKET
under REMOVAL & INSTALLATION.

z

Replace the front and/or rear disc brake hardware. See DISC BRAKE HARDWARE under
REMOVAL & INSTALLATION.

D. Replace the unevenly-worn, loose or damaged disc brake pads as a complete axle set. See BRAKE

PADS under REMOVAL & INSTALLATION.

If the inspection and replacement was completed, go to step 12 .

8.

A. Inspect the disc brake calipers, brake hoses and brake pipes for evidence of an external brake fluid

leak.

B. Replace any components found to be leaking brake fluid. Refer to the following procedures as

required:

z

Perform brake caliper overhaul. See BRAKE CALIPER under OVERHAUL.

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Replace appropriate brake hose. See BRAKE HOSE under REMOVAL &
INSTALLATION.

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Replace brake pipe. See BRAKE PIPE under REMOVAL & INSTALLATION.

If the source of the leak causing contamination of the pads was found and corrected, go to step 11 .
If the source of the leak causing contamination of the pads was not found and corrected, go to step
9 .

9.

A. Inspect the wheel drive shaft outer seals, if equipped, for damage and evidence of a grease leak.

B. Replace any wheel drive shaft seal that is found to be leaking grease which may be the source of

the contamination to the pads. See AXLE SHAFTS article in DRIVELINE/AXLES.

C. Inspect the rear axle seals for damage and evidence of a lubricant leak.

D. Replace any rear axle seal that is found to be leaking lubricant which may be the source of the

contamination to the pads. See AXLE SHAFTS article in DRIVELINE/AXLES.

If the source of the leak causing contamination of the pads was found and corrected, go to step 11 . If the
source of the leak causing contamination of the pads was not found and corrected, go to step 10 .

10.

A. Inspect the automatic transmission cooling system lines, if equipped, for damage and evidence of

an external fluid leak which may be the source of the contamination to the pads.

B. Inspect the power steering system hoses for damage and evidence of an external fluid leak which

may be the source of the contamination to the pads.

C. Replace any components found to be leaking fluid which may be the source of the contamination to

2004 Hummer H2

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the pads.

If the source of the leak causing contamination of the pads was found and corrected, go to step 11 .

11.

A. Clean the remaining disc brake system components to remove any traces of the contaminant.

B. Remove the front and/or rear disc brake calipers, as appropriate, from the mounting brackets and

support the calipers. See BRAKE CALIPER under REMOVAL & INSTALLATION.

C. Inspect the disc brake caliper mounting/sliding hardware for the following conditions: See DISC

BRAKE MOUNTING & HARDWARE under ADJUSTMENTS & INSPECTION.

z

Binding or seized hardware.

z

Distorted, worn, damaged or missing hardware components.

D. Replace the caliper mounting/sliding hardware components as required. See DISC BRAKE

HARDWARE under REMOVAL & INSTALLATION.

E. Replace the contaminated disc brake pads as a complete axle set. See BRAKE PADS under

REMOVAL & INSTALLATION.

If the cleaning, inspection and replacement was completed, go to step 12 .

12. Visually inspect each of the disc brake rotor shields/backing plates for evidence of contact with the brake

rotors. If any of the brake rotor shields/backing plates are contacting the brake rotors, go to step 13 . If
any of the brake rotor shields/backing plates are not contacting the brake rotors, go to step 14 .

13. Repair or replace the disc brake rotor shields/backing plates as required. See DISC BRAKE

SPLASHSHIELD under REMOVAL & INSTALLATION. If the repair or replacement was completed,
go to step 14 .

14. Make the following determination individually for each rotor:

A. Check the thickness of each of the disc brake rotors.

B. Make a determination for each brake rotor if the rotor can be refinished and remain above the

minimum requirements.

See BRAKE ROTOR THICKNESS MEASUREMENT under ADJUSTMENTS & INSPECTION. If
the disc brake rotors meet the minimum requirements for refinishing, go to step 15 . If the disc brake
rotors DO NOT meet the minimum requirements for refinishing, go to step 18 .

15.

Inspect each of the disc brake rotors for thickness variation that exceeds the maximum acceptable level.

CAUTION: DO NOT disconnect the hydraulic brake flex hoses from the calipers.

NOTE:

Support the brake caliper with heavy mechanic's wire, or equivalent,
whenever it is separated from its mount and the hydraulic flexible brake
hose is still connected. Failure to support the caliper in this manner will
cause the flexible brake hose to bear the weight of the caliper, which may
cause damage to the brake hose and in turn may cause a brake fluid leak.

NOTE:

Make the following determination individually for each rotor.

2004 Hummer H2

2003-04 BRAKES Disc - Hummer