Hummer H2. Manual - part 2115

Fig. 10: Bleeding Power Steering System 
Courtesy of GENERAL MOTORS CORP. 

3. Attach the J 43485 to the J 35555 or equivalent. See Special Tools and Equipment .  

4. Place the J 43485 on or in the pump reservoir filler neck. See Special Tools and Equipment .  

5. Apply a vacuum of 68 kPa (20 in Hg) maximum.  

6. If the vacuum drops again, repair or replace the pump. If the vacuum holds steady, continue to check the 

other parts of the steering system. 

IMPORTANT: Fluid must be free from bubbles and foam. Be aware of periodic bubbles 

that indicate a loose connection or leaking O-ring seal in the return hose 
or the pressure hose. 

 

2004 Hummer H2 

2004 STEERING Power Steering System - Hummer H2

  

7. Observe the fluid.  

8. If condition persists, replace the following parts: 

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The return hose clamps  

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The return hose O-rings  

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The pressure hose O-rings  

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The gear cylinder line O-rings  

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The reservoir to pump O-ring  

9. Repeat the bleed procedure from the beginning.  

10. Drive the vehicle approximately 16 km (10 mi) in order to warm the system to operating temperature. 

Evaluate vehicle on a smooth flat surface.  

11. Verify the following conditions: 

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There is smooth power assist.  

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The vehicle operates quietly.  

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The pump maintains the proper fluid level.  

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There is no leaking in the steering system.  

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The fluid is free of foam or discoloration.  

CHECKING AND ADDING POWER STEERING FLUID 

1. Clean the area surrounding the reservoir cap.  

2. Remove the reservoir cap.  

3. Inspect the power steering pump fluid level at regular intervals. Use the appropriate procedure below. 

Add fluid when required. Refer to Fluid and Lubricant Recommendations in Maintenance and 
Lubrication. 

Fluid Is Cold 

1. Remove the reservoir cap.  

2. Inspect the fluid level on the capstick.  

3. Ensure that the fluid level is between the bottom of the COLD/FULL mark and the end of the 

capstick.  

Fluid Is Hot 

Fluid must be free from discoloration.

NOTE:

When adding fluid or making a complete fluid change, always use the proper 
power steering fluid. Failure to use the proper fluid will cause hose and seal 
damage and fluid leaks.

 

2004 Hummer H2 

2004 STEERING Power Steering System - Hummer H2

  

1. Run the engine until the fluid reaches about 80°C (170°F).  

2. Turn the engine OFF.  

3. Remove the reservoir cap.  

4. Inspect the fluid level on the capstick.  

5. Ensure that the fluid level is between the HOT/FULL and the COLD/FULL marks on the capstick.  

4. If the fluid level is low, add power steering fluid to the proper level.  

5. Install the reservoir cap.  

6. When checking the fluid level after servicing the steering system, bleed the air from the system. Refer to 

Bleeding the Power Steering System .  

FLUSHING THE POWER STEERING SYSTEM 

1. Turn off the engine.  

2. Raise the front end of the vehicle off the ground until the tires and wheels turn freely. Refer to Lifting 

and Jacking the Vehicle in General Information.  

3. Place a large container under the fluid return hose in order to collect the draining fluid.  

4. Remove the fluid return hose at the power steering pump reservoir inlet connection.  

5. Plug the reservoir return hose inlet connection on the power steering pump. 

6. Run the engine at idle while an assistant maintains the fluid level at FULL COLD in the reservoir using 

new approved power steering fluid.  

7. Turn off the engine.  

8. Turn the steering wheel fully to the left and to the right.  

9. Remove the plug from the pump reservoir inlet connection.  

10. Install the fluid return hose to the pump reservoir.  

11. Maintain the fluid level at FULL COLD.  

12. Operate the engine at idle for approximately 15 minutes.  

13. Repeat steps 3-5.  

14. Inspect the power steering fluid for the following indications of contamination: 

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Milky fluid - water  

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Brown fluid - burnt  

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Plastic debris or dirt chunks  

IMPORTANT: Do not reuse any drained power steering fluid regardless of appearance or 

condition.

IMPORTANT:

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This step may require 4 L (4 qt) of power steering fluid until the 
draining fluid appears clear.  

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Do not run the engine without the power steering fluid level at FULL 
COLD.  

 

2004 Hummer H2 

2004 STEERING Power Steering System - Hummer H2

  

15. If the fluid is contaminated, repeat steps 6-12 in order to complete a third flush.  

16. Remove the plug from the pump reservoir inlet connection.  

17. Install the fluid return hose to the pump reservoir.  

18. Clean any spilled fluid.  

19. Bleed the power steering system. Refer to Bleeding the Power Steering System .  

POWER STEERING PULLEY REPLACEMENT 

Tools Required 

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J 25034-C Power Steering Pump Pulley Remover. See Special Tools and Equipment .  

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J 25033-C Power Steering Pump Pulley Installer. See Special Tools and Equipment .  

Removal Procedure 

1. Remove the upper fan shroud. Refer to Fan Shroud Replacement in Engine Cooling.  

2. Remove the drive belt. Refer to Drive Belt Replacement - Accessory in Engine Mechanical. 

 

2004 Hummer H2 

2004 STEERING Power Steering System - Hummer H2