Hummer H2. Manual - part 797

Fig. 29: Removing/Installing Rotor (Front) 
Courtesy of GENERAL MOTORS CORP. 

Installation 

1. Use Rotor Resurfacing Kit (J-42450-A) to clean all rust and contaminants from the mating surface of the 

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

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

 

2004 Hummer H2 

2003-04 BRAKES Disc - Hummer

  

hub flange. Use the Wheel Hub Resurfacing Kit (J-41013) to clean all rust and contaminants from the 
inside diameter of the hat section of the brake rotor to prevent any foreign material from getting between 
the brake rotor and the hub flange. Inspect the mating surfaces of the hub/axle flange and the rotor to 
ensure that there are no foreign particles or debris remaining.  

2.  

Align the rotor to its original position on the hub, if applicable, and install the rotor. If the brake rotor was 
removed and installed as part of a brake system repair, measure the assembled Lateral Runout (LRO) of 
the brake rotor to ensure optimum performance of the disc brakes. See appropriate ANTI-LOCK article.  

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

specifications. See appropriate ANTI-LOCK article. Install the caliper and caliper mounting bracket 
assembly.  

4. Perform the following procedure before installing the brake caliper bracket mounting bolts. Remove all 

traces of the original adhesive patch. Clean the threads of the bolt with brake parts cleaner or the 
equivalent and allow to dry. Apply Threadlocker (GM P/N 12345493) to the threads of the bolt.  

5. Install the 2 caliper bracket mounting bolts. Tighten the brake caliper bracket mounting bolts to 

specification. See TORQUE SPECIFICATIONS . Install the tire and wheel assembly. Lower the 
vehicle.  

6. With the engine OFF, gradually apply the brake pedal to approximately 2/3 of its travel distance. Slowly 

release the brake pedal. Wait 15 seconds, then repeat step until a firm pedal is obtained. This will 
properly seat the brake caliper pistons and brake pads. Fill the master cylinder reservoir to the proper 
level with clean brake fluid.  

Removal (Rear) 

1. Release the park brake. Raise and suitably support the vehicle. Remove the tire and wheel assembly. 

Mark the relationship of the rotor to the hub.  

2. Install a C-clamp over the body of the brake caliper, with the C-clamp ends against the rear of the caliper 

body and the outboard disc brake pad. See Fig. 14 . Slowly tighten the C-clamp until the pistons are 
pushed into the caliper bores enough to remove the caliper from the pads. Remove the C-clamp from the 
caliper. Remove the 2 brake caliper bracket mounting bolts.  

3.  

Remove the brake caliper and brake caliper mounting bracket as an assembly and support with heavy 
mechanic's wire or equivalent. DO NOT disconnect the hydraulic brake flexible hose from the caliper. 
Remove the rotor retaining push nuts from the wheel studs, if applicable. It may be necessary to strike the 

CAUTION: If the rotor was removed using the jack screw method you must 

ensure that the hub flange is free of nicks or marks caused by this 
procedure. Remove all raised nicks or marks before installing the 
rotor. 

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 

2003-04 BRAKES Disc - Hummer

  

end of the hub or the rotor with a deadblow hammer to separate the rotor from the hub.  

4. Remove the rotor by slowly turning the rotor while pulling the rotor away from the axle. See Fig. 30 .  

Fig. 30: Removing/Installing Brake Rotor (Rear) 
Courtesy of GENERAL MOTORS CORP. 

Installation 

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

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

 

2004 Hummer H2 

2003-04 BRAKES Disc - Hummer

  

1. Use the Wheel Hub Resurfacing Kit (J-42450-A) to clean all rust and contaminants from the mating 

surface of the hub flange. Use the Rotor Resurfacing Kit (J-41013) to clean all rust and contaminants 
from the inside diameter of the hat section of the brake rotor to prevent any foreign material from getting 
between the brake rotor and the hub flange.  

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

particles or debris remaining. Align the rotor to its original position on the hub, if applicable, and install 
the rotor by slowly turning the rotor while pushing the rotor towards the axle.  

3. If the brake rotor was removed and installed as part of a brake system repair, measure the Assembled 

Lateral Runout (LRO) of the brake rotor to ensure optimum performance of the disc brakes. If the brake 
rotor assembled LRO measurement exceeds the specification, bring the LRO to within specifications.  

4. Install the caliper and the bracket as an assembly to the vehicle. Perform the following procedure before 

installing the caliper bracket mounting bolts. 

z

Remove all traces of the original adhesive patch.  

z

Clean the threads of the bolt with brake parts cleaner or the equivalent and allow to dry.  

z

Apply Threadlocker (GM P/N 12345493) to the threads of the bolt.  

5. Install the caliper bracket mounting bolts. Tighten the brake caliper bracket mounting bolts to 

specification. See TORQUE SPECIFICATIONS . Install the tire and wheel assembly. Lower the 
vehicle.  

6. With the engine OFF, gradually apply the brake pedal to approximately 2/3 of its travel distance. Slowly 

release the brake pedal. Wait 15 seconds, then repeat step until a firm pedal is obtained. This will 
properly seat the brake caliper pistons and brake pads.  

7. Fill the master cylinder reservoir to the proper level with clean brake fluid.  

DISC BRAKE HARDWARE 

Removal (Front) 

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 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 disc brake hardware. See DISC BRAKE MOUNTING & HARDWARE INSPECTION 

under ADJUSTMENTS & INSPECTION.  

4. 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.  

2. Install the disc brake pad retainers to the disc brake caliper mounting bracket. Install the disc brake pads 

to the disc brake caliper mounting bracket. See BRAKE PADS .  

3. Install the disc brake caliper to the caliper mounting bracket. With the engine OFF, gradually apply the 

 

2004 Hummer H2 

2003-04 BRAKES Disc - Hummer