Hummer H3. Manual — part 644

1. Turn the ignition ON. Allow the pump and motor to run as required. The pump and motor

will stop automatically and may run up to 10 seconds.

2. Depress the brake pedal 4 times.

3. Confirm that brake fluid returns to the reservoir.

4. Repeat steps 1-3 until all air is purged from the accumulator circuit (return fluid is clear and

free from air).

5. With the ignition OFF, depress and release the brake pedal 20 times to deplete accumulator

pressure. If the brake fluid clouds and has air mixed with the fluid, wait until the fluid clears
to proceed.

6. Turn the ignition ON and depress the pedal 20 times quickly. The pump and motor will be

activated.

7. Turn the ignition OFF and repeat step 5 again. If the brake fluid clouds and has air mixed

with the fluid, wait until the fluid clears to proceed.

8. Turn the ignition ON to activate the pump and motor. Allow the pump and motor to stop

automatically. The pump and motor will run about 10 seconds.

9. Install a scan tool to the vehicle.

10. Start the engine and allow the engine to idle.

11. Depress the brake pedal firmly and maintain steady pressure on the pedal.

12. Using the scan tool, begin the automated bleed procedure.

13. Follow the instructions on the scan tool to complete the automated bleed procedure. Release

the brake pedal between each test sequence.

14. Turn the ignition OFF.

15. Remove the scan tool from the vehicle.

16. Fill the brake master cylinder reservoir to the maximum-fill level with Delco Supreme 11®

GM P/N 12377967 (Canadian P/N 992667) or equivalent DOT-3 brake fluid from a clean,
sealed brake fluid container.

IMPORTANT: Perform steps 1-4 below to bleed the HBCi accumulator circuit

prior to performing a base brake bleed.

IMPORTANT: The base hydraulic brake system must be bled before

proceeding. If you have not yet performed the base hydraulic
brake system bleeding procedure, refer to Hydraulic Brake
System Bleeding (Manual) or Hydraulic Brake System
Bleeding (Pressure) for hydraulic brakes before proceeding.

2007 Hummer H3

2007 BRAKES Antilock Brake System - H3

17. Bleed the hydraulic brake system. Refer to Hydraulic Brake System Bleeding (Manual)

or Hydraulic Brake System Bleeding (Pressure) for hydraulic brakes.

18. With the ignition OFF, apply the brakes 20 times or until the brake pedal becomes firm, in

order to deplete the brake booster power reserve.

19. Slowly depress and release the brake pedal. Observe the feel of the brake pedal.

20. If the pedal feels spongy, repeat the automated bleeding procedure. If the brake pedal still

feels spongy after repeating the automated bleeding procedure inspect the brake system for
external leaks. Refer to Brake System External Leak Inspection .

21. Turn the ignition key ON, with the engine OFF; check to see if the brake system warning

lamp remains illuminated.

22. If the brake system warning lamp remains illuminated, DO NOT allow the vehicle to be

driven until it is diagnosed and repaired. Refer to Symptoms - Hydraulic Brakes for
hydraulic brakes.

23. Drive the vehicle to exceed 13 kph (8 mph) to allow ABS initialization to occur. Observe

brake peal feel.

24. If the brake pedal feels spongy, repeat the automated bleeding procedure until a firm brake

pedal is obtained.

ANTILOCK BRAKE SYSTEM AUTOMATED BLEED PROCEDURE (WITH RPO BRM

CAUTION: Refer to DOT 4 BRAKE FLUID CAUTION .

CAUTION: Refer to Brake Fluid Irritant Caution .

CAUTION: Do not remove the reservoir cap while depressing and

releasing the brake pedal. If the cap is removed while
depressing and releasing the brake pedal, pressurized brake
fluid being returned to the reservoir may leave the reservoir.
Personal injury or vehicle damage could result.

NOTE:

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

NOTE:

When adding fluid to the brake master cylinder reservoir, use only
GM Vehicle Care Brake and Clutch Fluid Super DOT-4, GM P/N

2007 Hummer H3

2007 BRAKES Antilock Brake System - H3

1. Turn the ignition ON. Allow the pump and motor to run as required. The pump and motor

will stop automatically and may run up to 10 seconds.

2. Depress the brake pedal 4 times.

3. Confirm that brake fluid returns to the reservoir.

4. Repeat steps 1-3 until all air is purged from the accumulator circuit (return fluid is clear and

free from air).

5. With the ignition OFF, depress and release the brake pedal 20 times to deplete accumulator

pressure. If the brake fluid clouds and has air mixed with the fluid, wait until the fluid clears
to proceed.

6. Turn the ignition ON and depress the pedal 20 times quickly. The pump and motor will be

activated.

7. Turn the ignition OFF and repeat step 5 again. If the brake fluid clouds and has air mixed

with the fluid, wait until the fluid clears to proceed.

8. Turn the ignition ON to activate the pump and motor. Allow the pump and motor to stop

automatically. The pump and motor will run about 10 seconds.

9. Install a scan tool to the vehicle.

88958860 (Canadian P/N 88901244) or equivalent DOT-4 brake fluid
from a clean, sealed 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:

Do Not allow the HBCi pump and motor to run more than 1 minute
continuously. Allow 2 minutes cool down time between pump run
times. Extended pump and motor run time could create excessive
heat and damage the pump and motor assembly.

IMPORTANT: Perform steps 1-4 below to bleed the HBCi accumulator circuit

prior to performing a base brake bleed.

IMPORTANT: The base hydraulic brake system must be bled before

proceeding. If you have not yet performed the base hydraulic
brake system bleeding procedure, refer to Hydraulic Brake
System Bleeding (Manual) or Hydraulic Brake System
Bleeding (Pressure) for hydraulic brakes before proceeding.

2007 Hummer H3

2007 BRAKES Antilock Brake System - H3

10. Start the engine and allow the engine to idle.

11. Depress the brake pedal firmly and maintain steady pressure on the pedal.

12. Using the scan tool, begin the automated bleed procedure.

13. Follow the instructions on the scan tool to complete the automated bleed procedure. Release

the brake pedal between each test sequence.

14. Turn the ignition OFF.

15. Remove the scan tool from the vehicle.

16. Fill the brake master cylinder reservoir to the maximum-fill level with brake and clutch

fluid Super DOT-4 GM P/N 88958860 (Canadian P/N 88901244) or equivalent DOT-4
brake fluid from a clean, sealed brake fluid container.

17. Bleed the hydraulic brake system. Refer to Hydraulic Brake System Bleeding (Manual)

or Hydraulic Brake System Bleeding (Pressure) for hydraulic brakes.

18. With the ignition OFF, apply the brakes 20 times or until the brake pedal becomes firm, in

order to deplete the brake booster power reserve.

19. Slowly depress and release the brake pedal. Observe the feel of the brake pedal.

20. If the pedal feels spongy, repeat the automated bleeding procedure. If the brake pedal still

feels spongy after repeating the automated bleeding procedure inspect the brake system for
external leaks. Refer to Brake System External Leak Inspection .

21. Turn the ignition key ON, with the engine OFF; check to see if the brake system warning

lamp remains illuminated.

22. If the brake system warning lamp remains illuminated, DO NOT allow the vehicle to be

driven until it is diagnosed and repaired. Refer to Symptoms - Hydraulic Brakes for
hydraulic brakes.

23. Drive the vehicle to exceed 13 kph (8 mph) to allow ABS initialization to occur. Observe

brake peal feel.

24. If the brake pedal feels spongy, repeat the automated bleeding procedure until a firm brake

pedal is obtained.

BRAKE MASTER CYLINDER WITH POWER BRAKE BOOSTER AND CHASSIS CONTROL
MODULE REPLACEMENT (LHD)

Removal Procedure

CAUTION: Refer to Brake Fluid Irritant Caution .

NOTE:

Refer to Brake Fluid Effects on Paint and Electrical Components

2007 Hummer H3

2007 BRAKES Antilock Brake System - H3