Power Steering Bleeding: Service and Repair

Notice: When adding fluid or making a complete fluid change, always use a power steering fluid meeting GM Spec. No. 9985010 or equivalent. Fluid for cold climates is also available through GM Dealerships; refer to Specifications for further information. Failure to use the proper power steering fluid can cause power steering hose and seal damage, fluid leaks and pump failure.

Bleed the power steering system in the following situations:
- After replacing any component
- After disconnecting the fluid line
- Whenever a steering system noise is present

Perform the power steering system bleeding procedure for the following reasons:
- In order to prevent pump damage
- In order to ensure proper system operation
- In order to stop steering system noise

When filling the power steering fluid reservoir, use only clean, new power steering fluid. Refer to the table below for the proper fluid guidelines:

BLEEDING POWER STEERING SYSTEM





Before bleeding the power steering system, perform the following procedures:

1. Inspect the hoses.
Ensure that the hoses do not touch any other part of the vehicle. A hose that touches the following components may cause steering system noise:
- The frame
- The body
- The engine





2. Inspect the hose connections.
Ensure that all hose connections are tight. Loose connections might not leak but may allow air into the system.

BLEEDING PROCEDURE





1. Turn the ignition switch to the OFF position.





2. Raise the front wheels off the ground.





3. Turn the steering wheel full left.





4. Fill the fluid reservoir to the FULL COLD level. Do not reinstall the cap.





5. Ask an assistant to inspect the fluid level and condition.
Do not turn on the engine.
Turn the steering wheel lock-to-lock at least 20 times.
On systems with long return lines or fluid coolers turn the steering wheel lock-to-lock at least 40 times.
- Trapped air may cause the fluid to overflow. Thoroughly clean any spilled fluid in order to allow for leak inspection.
- Verify that the fluid level remains at the FULL COLD level.





6. While turning the wheel, inspect the fluid constantly. Bubbles are not allowed.
7. If bubbles are not present, proceed to the next step.
If any bubbles are present, inspect the connections again. Periodic bubbles may indicate the following conditions in either the return hose or the pressure hose:
Repeat the two previous steps.
- A loose connection
- A leaky O-ring seal





8. Complete the following steps:
8.1. Start the engine.
5.2. With the engine idling, maintain the fluid level.
8.3. Reinstall the cap.





9. Return the wheels to the center.
10. Lower the front wheels to the ground.
11. Run the engine for 2 minutes.





12. Turn the steering wheel in both directions.
13. Verify that the following conditions exist:
- Smooth power assist
- Noiseless operation
- Proper fluid level
- No system leaks
- Proper fluid condition
- No bubbles
- No foam
- No discoloration

14. If all of the above conditions apply, then the procedure is complete. If any problem remains, proceed to the next step.
15. If foam or bubbles are present in the fluid or the fluid is discolored (milky, opaque, or a light tan color), complete the following steps:
15.1. Turn the ignition switch to the OFF position.
15.2. Wait 2 minutes.
15.3. Inspect the hose connections again.
15.4. Complete the following steps:
15.4.1. Start the engine.
15.4.2. With the engine idling, maintain the fluid level.
15.4.3. Reinstall the cap.
15.5. Return the wheels to the center.
15.6. Lower the front wheels to the ground.
15.7. Run the engine for 2 minutes.
15.8. Turn the steering wheel in both directions.
15.9. If a fluid condition persists, inspect the following components. Replace any components as necessary:
- The return hose clamps
- The return hose O-rings
- The pressure hose O-rings
- The gear cylinder line O-rings

16. Fill the system. Refer to Fluid Specifications.
17. Repeat the entire bleed procedure for each possible cause.





18. If the pump whines or groans, complete the following steps:
18.1. With the engine running, inspect the hoses again for possible contact with the following components:
- The frame
- The body
- The engine

18.2. If no contact is found, follow one of the two methods below in order to cool down the fluid and repressurize the system.
Method 1: Normal Cool Down
18.2.1. Turn the engine OFF.
18.2.2. Wait for the system to cool.
18.2.3. Install the reservoir cap.
Method 2: Partial Fluid Replacement
18.2.4. Turn the engine OFF.
18.2.5. Use a suction device in order to remove the fluid from the reservoir.
18.2.6. Refill the reservoir using cool, clean fluid.
18.2.7. Install the reservoir cap.
18.3. After either method of cooling, start the engine. Allow the engine to reach operating temperature.
18.4. If the noise persists, remove and replace the power steering pump.
18.5. Repeat the entire bleeding procedure following the pump replacement.