GM Service Manual Online
For 1990-2009 cars only

Power Steering System Flushing ZF

    Important: Do not reuse any drained power steering fluid regardless of appearance or condition.

  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.
  3. Place a large container under the electro-hydraulic pump in order to collect the draining fluid.

  4. Object Number: 2037931  Size: SH
  5. Remove the fluid return hose (1) at the power steering pump and reconnect the supply line.
  6. Plug the reservoir return hose inlet connection (2) on the power steering pump and position return hose so fluid will drain into the container.
  7. Important: This step may require 4 L (4 qt) of power steering fluid until the draining fluid appears clear.

  8. With the key on the engine OFF, turn the steering wheel fully to the left and to the right while an assistant maintains the minimum fluid level in the reservoir using NEW approved power steering fluid.
  9. Continue until the fluid from the return hose runs clear.

  10. Remove the plug from the pump inlet connection.
  11. Notice: Refer to Fastener Notice in the Preface section.

  12. Install the supply and return lines to the electro-hydraulic supply unit.
  13. Do NOT install new seals at this time.

    Tighten
    Tighten the bolt to 16 N·m (12 lb ft).

  14. Check the fluid level and add power steering fluid if necessary. Refer to Checking and Adding Power Steering Fluid.
  15. Important: Do NOT run the engine without the power steering fluid at a minimum system level.

  16. Start and run the vehicle, turning the steering wheel from lock to lock several times for approximately 1 minute.
  17. Inspect the power steering fluid for the following indications of contamination:
  18. • Milky fluid -- water
    • Brown fluid -- burnt
    • Plastic debris or dirt chunks
  19. If the fluid is contaminated, repeat steps 3-11.
  20. Install the supply and return lines to the electro-hydraulic supply unit with NEW seals.
  21. Tighten
    Tighten the bolt to 16 N·m (12 lb ft).

    Important: Do NOT run the engine without the power steering fluid at a minimum system level.

  22. Check the fluid level and add power steering fluid if necessary. Refer to Checking and Adding Power Steering Fluid.
  23. Bleed the power steering system. Refer to Power Steering System Bleeding.
  24. Lower the vehicle and check the power steering system for leaks. Refer to Power Steering Fluid Leaks.

Power Steering System Flushing TRW

    Important: Do not reuse any drained power steering fluid regardless of appearance or condition.

  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.
  3. Place a large container under the electro-hydraulic pump in order to collect the draining fluid.

  4. Object Number: 2037930  Size: SH
  5. Remove the fluid return hose (1) at the power steering pump.
  6. Plug the reservoir return hose inlet connection (2) on the power steering pump and position return hose so fluid will drain into the container.
  7. Important: This step may require 4 L (4 qt) of power steering fluid until the draining fluid appears clear.

  8. With the key on the engine OFF, turn the steering wheel fully to the left and to the right while an assistant maintains the minimum fluid level in the reservoir using NEW approved power steering fluid.
  9. Continue until the fluid from the return hose runs clear.

  10. Remove the plug from the pump inlet connection.
  11. Install the supply and return lines to the electro-hydraulic supply unit.
  12. Do NOT install new seals or hose clamp at this time.

  13. Check the fluid level and add power steering fluid if necessary. Refer to Checking and Adding Power Steering Fluid.
  14. Important: Do NOT run the engine without the power steering fluid at a minimum system level.

  15. Start and run the vehicle, turning the steering wheel from lock to lock several times for approximately 1 minute.
  16. Inspect the power steering fluid for the following indications of contamination:
  17. • Milky fluid -- water
    • Brown fluid -- burnt
    • Plastic debris or dirt chunks
  18. If the fluid is contaminated, repeat steps 3-11.
  19. Notice: Refer to Fastener Notice in the Preface section.

    Important: New seals for the TRW supply line are not needed.

  20. Install the supply and return lines to the electro-hydraulic supply unit with NEW seals rings and hose clamp.
  21. Tighten
    Tighten the bolt to 30 N·m (22 lb ft).

    Important: Do NOT run the engine without the power steering fluid at a minimum system level.

  22. Check the fluid level and add power steering fluid if necessary. Refer to Checking and Adding Power Steering Fluid.
  23. Bleed the power steering system. Refer to Power Steering System Bleeding.
  24. Lower the vehicle and check the power steering system for leaks. Refer to Power Steering Fluid Leaks.