Power Steering System: Overview Chevrolet TrailBlazer I

Test Description

The numbers below refer to the step numbers on the diagnostic table.

1. 5. This step tests the system for restrictions.
2. 7. This step tests the following components for the following conditions

1. The pump for internal leaks
2. The power steering pipes for kinks

1. 8. This step tests the ability of the pump to regulate flow at maximum pressure.
2. 10. This step tests the ability of the pump to regulate flow under normal operating conditions.
3. 12. This step tests the internal components of the pump and the gear.

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Tools Required

1. J 35555 Metal Mityvac
2. J 43485 Power Steering Bleeder Adapter

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1. Verify that the hoses do not touch any other part of the vehicle. IMPORTANT: Loose connections may not leak, but could allow air into the steering system.
2. Verify that all hose connections are tight. NOTE: If the power steering system has been serviced, an accurate fluid level reading cannot be obtained unless air is bled from the steering system. The air in the fluid may cause pump cavitation noise and may cause pump damage over a period of time. IMPORTANT: Maintain the fluid level throughout the bleed procedure.
3. Remove the pump reservoir cap. IMPORTANT: Use clean, new power steering fluid only.
4. Fill the pump reservoir with fluid to the FULL COLD level.
5. Attach the J 43485 to the J 35555 or equivalent.
6. Place the J 43485 on or in the pump reservoir filler neck.
7. Apply a vacuum of 68 kPa (20 in Hg) maximum.
8. Wait 5 minutes. Typical vacuum drop is 7-10 kPa (2-3 in Hg). If the vacuum does not remain steady, refer to Excessive Vacuum Drop Diagnosis at the end of this procedure.
9. Remove the J 43485 and the J 35555.
10. Reinstall the pump reservoir cap.
11. Start the engine. Allow the engine to idle.
12. Turn off the engine.
13. Verify the fluid level. Repeat steps 11 - 13 until the fluid stabilizes. IMPORTANT: Do not turn steering wheel to lock.
14. Start the engine. Allow the engine to idle.
15. Turn the steering wheel 180-360 degrees in both directions 5 times.
16. Switch the ignition off. 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.
17. Verify the fluid level.
18. Remove the pump reservoir cap.
19. Attach the J 43485 to the J 35555 or equivalent.
20. Place the J 43485 on or in the pump reservoir filler neck.
21. Apply a vacuum of 68 kPa (20 in Hg) maximum.
22. Wait 5 minutes.
23. Remove the J 43485 and the J 35555.
24. Verify the fluid level.
25. Reinstall the pump reservoir cap.

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1. If the vacuum continues to drop, remove the pressure and return hose from the pump.
2. Install the plugs (1, 2) supplied with the J 43485 into the pressure and return port.
3. Attach the J 43485 to the J 35555 or equivalent.
4. Place the J 43485 on or in the pump reservoir filler neck.
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. Fluid must be free from discoloration.
7. Observe the fluid.
8. If condition persists, replace the following parts: The return hose clamps The return hose O-rings The pressure hose O-rings The gear cylinder line O-rings 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: There is smooth power assist. The vehicle operates quietly. The pump maintains the proper fluid level. There is not any leaking in the steering system. The fluid is free of foam or discoloration.