Hummer H2. Manual — part 807

2004 Hummer H2

2003-04 BRAKES Disc - Hummer

Fig. 57: Removing/Installing Park Brake Warning Light Switch Mounting Bolt
Courtesy of GENERAL MOTORS CORP.

OVERHAUL

BRAKE ROTOR REFINISHING

CAUTION: Avoid taking the following actions when you service wheel brake parts:

DO NOT grind brake linings. DO NOT sand brake linings. DO NOT clean
wheel brake parts with a dry brush or with compressed air. 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.

CAUTION: The disc brake rotors DO NOT require refinishing as part of routine brake

system service. New disc brake rotors DO NOT require refinishing. DO
NOT refinish disc brake rotors in an attempt to correct the following
conditions:

z

Brake system noise - squeal, growl, groan.

z

Uneven and/or premature disc brake pad wear.

z

Superficial or cosmetic corrosion/rust of the disc brake rotor friction
surface.

z

Scoring of the disc brake rotor friction surface less than the
maximum allowable specification.

Before refinishing a brake rotor, the rotor MUST first be checked for
adequate thickness to allow the rotor to be refinished and remain above
the minimum allowable thickness after refinish specification. See BRAKE
ROTOR THICKNESS MEASUREMENT under ADJUSTMENTS &
INSPECTION. Disc brake rotors should only be refinished if they have
adequate thickness to be refinished and if one or more of the following
conditions exist:

z

Thickness variation in excess of the maximum allowable
specification.

z

Excessive corrosion/rust and/or pitting.

z

Cracks and/or heat spots.

z

Excessive blueing discoloration.

z

Scoring of the disc brake rotor surface in excess of the maximum
allowable specification.

2004 Hummer H2

2003-04 BRAKES Disc - Hummer

1. Using the Wheel Hub Resurfacing Kit (J 42450-A), thoroughly clean any rust or corrosion from the

mating surface of the hub/axle flange.

2. Using the Rotor Resurfacing Kit (J 41013), thoroughly clean any rust or corrosion from the mating

surface and mounting surface of the brake rotor.

3. Inspect the mating surfaces of the hub/axle flange and the rotor to ensure that there are no foreign

particles or debris remaining.

4. Mount the brake rotor to the brake lathe according to the lathe manufacturer's instructions, ensuring that

all mounting attachments and adapters are clean and free of debris.

5. Ensure that any vibration dampening attachments are securely in place.

6. With the brake lathe running, slowly bring in the cutting tools until they just contact the brake rotor

friction surfaces.

7. Observe the witness mark on the brake rotor. If the witness mark extends approximately three-quarters or

more of the way around the brake rotor friction surface on each side, the brake rotor is properly mounted
to the lathe.

8. If the witness mark does not extend three-quarters or more of the way around the brake rotor, re-mount

the rotor to the lathe.

9. Following the brake lathe manufacturer's instructions, refinish the brake rotor.

10. After each successive cut, inspect the brake rotor thickness. See BRAKE ROTOR THICKNESS

MEASUREMENT under ADJUSTMENTS & INSPECTION.

11. If at any time the brake rotor exceeds the minimum allowable thickness after refinish specification, the

brake rotor must be replaced.

12. After refinishing the brake rotor, use the following procedure in order to obtain the desired non-

directional finish:

A. Follow the brake lathe manufacturer's recommended speed setting for applying a non-directional

finish.

B. Using moderate pressure, apply the non-directional finish:

z

If the lathe is equipped with a non-directional finishing tool, apply the finish with 120 grit
aluminum oxide sandpaper.

z

If the lathe is not equipped with a non-directional finishing tool, apply the finish with a
sanding block and 150 grit aluminum oxide sandpaper.

C. After applying a non-directional finish, clean each friction surface of the brake rotor with denatured

alcohol, or an equivalent approved brake cleaner.

Disc brake rotors may need to be refinished as part of the process for
correcting brake rotor assembled lateral runout (LRO) that exceeds the
maximum allowable specification.

CAUTION: Whenever the brake rotor has been separated from the hub/axle flange,

clean any rust or contaminants from the hub/axle flange and the brake
rotor mating surfaces. Failure to do this may result in increased
assembled lateral runout (LRO) of the brake rotor, which could lead to
brake pulsation.

2004 Hummer H2

2003-04 BRAKES Disc - Hummer

13. Remove the brake rotor from the brake lathe.

14. Measure the assembled Lateral Runout (LRO) of the brake rotor to ensure optimum performance of the

disc brakes. See BRAKE ROTOR SURFACE & WEAR INSPECTION under ADJUSTMENTS &
INSPECTION.

15. If the brake rotor assembled LRO measurement exceeds the specification, bring the LRO to within

specifications.

16. Inspect each of the disc brake rotors and determine if the rotors can be refinished and remain above the

minimum allowable thickness after refinish specification: Inspect the thickness of each of the disc brake
rotors. Inspect each of the disc brake rotors for excessive surface wear and/or lateral runout.

BRAKE CALIPER

Disassembly (Front)

1. Replace all the components included in the repair kits used to service this brake caliper. Lubricate the

rubber parts with NEW Delco Supreme 11(R) (GM P/N 12377967) or equivalent DOT-3 brake fluid to
make assembly easier.

2. If any hydraulic component is removed or disconnected, it may be necessary to bleed all or part of the

brake system. The torque values specified are for dry, non-lubricated fasteners. Perform the service

CAUTION: DO NOT place your fingers in front of the piston in order to catch or

protect the piston while applying compressed air. This could result in
serious injury.

CAUTION: Avoid taking the following actions when you service wheel brake parts:

DO NOT grind brake linings. DO NOT sand brake linings. DO NOT clean
wheel brake parts with a dry brush or with compressed air. 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.

CAUTION: Brake fluid may irritate eyes and skin. In case of contact, take the

following actions: Eye contact; rinse thoroughly with water. Skin contact;
wash with soap and water. If ingested, consult a physician immediately.

NOTE:

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