Hummer H2. Manual - part 798

brake pedal approximately 2/3 of its travel distance. Slowly release the brake pedal. Wait 15 seconds, 
then repeat step until a firm brake pedal is obtained. This will properly seat the brake caliper pistons and 
brake pads.  

Removal (Rear) 

1. Raise and support the vehicle. Remove the tire and wheel assembly. Remove the caliper from the 

mounting bracket and support the caliper with heavy mechanic's wire or equivalent. See BRAKE 
CALIPER . DO NOT disconnect the hydraulic brake flexible hose from the caliper.  

2. Remove the rear disc brake pads from the disc brake caliper mounting bracket. See BRAKE PADS . 

Remove the disc brake pad retainers from the disc brake caliper mounting bracket.  

3. Inspect the rear disc brake hardware. See DISC BRAKE MOUNTING & HARDWARE under 

ADJUSTMENTS & INSPECTION.  

4. Remove the caliper pins from the disc brake caliper mounting bracket. Remove the caliper pin boots from 

the disc brake caliper mounting bracket.  

Installation 

1. Lubricate the front brake caliper bushings, bolts and seals with high temperature silicone brake lubricant. 

Install the caliper pin boots to the disc brake caliper mounting bracket. Install the caliper pins to the disc 
brake caliper mounting bracket.  

2. Install the disc brake pad retainers to the disc brake caliper mounting bracket. See BRAKE PADS . 

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

3. Install the disc brake caliper to the caliper mounting bracket. See BRAKE CALIPER . With the engine 

OFF, gradually apply the brake pedal approximately 2/3 of its travel distance. Slowly release the brake 
pedal. Wait 15 seconds, then repeat until a firm brake pedal is obtained. This will properly seat the brake 
caliper pistons and brake pads.  

DISC BRAKE SPLASHSHIELD 

Removal & Installation (Front Only) 

Raise and support the vehicle. Remove the tire and wheel assembly. Remove the hub and bearing assembly. See 
appropriate FRONT article in SUSPENSION. Remove the splash shield. To install the splash shield, install the 
hub and bearing assembly. Install the tire and wheel assembly. Remove the safety stands. Lower the vehicle. 

 

2004 Hummer H2 

2003-04 BRAKES Disc - Hummer

  

Fig. 31: Removing & Installing Front Splash Shield 
Courtesy of GENERAL MOTORS CORP. 

HYDRAULIC BRAKE BOOSTER ACCUMULATOR 

Removal & Installation 

1. Apply the park brake and block the wheels. Depress brake pedal at least 10 times in order to relieve 

pressure in the accumulator. Remove the master cylinder from the hydraulic booster. See MASTER 
CYLINDER .  

2. Place the Accumulator Piston Compressor (J-26889) over the end of the accumulator. See Fig. 32 . Install 

the nut on the stud. Depress the accumulator with a C-clamp. If the accumulator does not move with 
moderate pressure, remove the C-clamp and depress the brake pedal 10 times in order to relieve pressure 
in the accumulator.  

3. Rotate the retaining ring until either end of the ring is under the access hole. See Fig. 33 . Depress and 

hold the retaining ring with a small tool inserted into the access hole.  

4. Remove the accumulator retainer ring using a small hook shaped tool. See Fig. 34 . Release the C-clamp. 

Remove the nut from the stud. Remove the Accumulator Piston Compressor (J-26889). Remove the 

CAUTION: The accumulator contains compressed gas. Always use the proper tools 

and follow the recommended procedures or personal injury may result. 
DO NOT apply heat to accumulator. DO NOT attempt to repair an 
inoperative accumulator. Always replace an inoperative accumulator with 
a NEW one. Dispose of an inoperative accumulator by drilling a 1/16" (1.5 
mm) diameter hole through the end of the accumulator can, opposite the 
"O" ring. 

CAUTION: Push rod removal is not recommended. Improper staking of the push rod 

to the hydroboost reaction piston can result in a loss of brakes. If the rod 
or seals require service, the entire unit must be replaced. 

 

2004 Hummer H2 

2003-04 BRAKES Disc - Hummer

  

accumulator and the "O" ring seal.  

5. To install, lubricate all of the seals and the metal friction points with power steering fluid. Install the 

accumulator and the "O" ring seal. Place the Accumulator Piston Compressor (J-26889) over the end of 
the accumulator.  

6. Install the nut on the stud. Depress the accumulator with a C-clamp. Install the accumulator retainer ring. 

Release the C-clamp. Remove the nut from the stud. Remove the Accumulator Piston Compressor (J-
26889).  

7. Install the master cylinder to the hydraulic booster. See MASTER CYLINDER . Release the park brake 

and unblock the wheels.  

Fig. 32: Using Accumulator Piston Compressor Tool 
Courtesy of GENERAL MOTORS CORP.

 

2004 Hummer H2 

2003-04 BRAKES Disc - Hummer

  

Fig. 33: Rotating Retaining Ring 
Courtesy of GENERAL MOTORS CORP.

 

2004 Hummer H2 

2003-04 BRAKES Disc - Hummer