How to Bleed a Power Steering Pump

Introduction

Bleeding a power steering pump is an essential maintenance procedure that removes trapped air from the hydraulic system. Air pockets can cause whining or groaning noises, erratic steering feel, and accelerated wear on critical pump components. Whether you have just installed a new pump, replaced hoses, or noticed symptoms of air in the system, a proper bleeding procedure will restore smooth, reliable steering performance.

Why Bleeding Is Necessary

Air enters the power steering system during component replacement, fluid top-offs, or hose repairs. Even small amounts of trapped air can cause:

• Loud whining, groaning, or squealing noises when turning
• Stiff or inconsistent steering effort
• Foamy or aerated fluid in the reservoir
• Premature pump wear due to cavitation

Fluid Recommendation: Use Power Steering Fluid

Important: We strongly recommend using dedicated power steering fluid in our pump assemblies. Do not substitute automatic transmission fluid (ATF) or universal hydraulic fluids unless explicitly specified in your vehicle's owner's manual. Using the correct fluid:

• Prevents seal degradation and fluid leaks
• Maintains proper viscosity across temperature ranges
• Reduces internal wear on pump vanes and housing
• Preserves warranty coverage on our pump assemblies

Tools and Materials Required

• Fresh power steering fluid (manufacturer-recommended specification)
• Clean turkey baster or fluid suction pump
• Clean funnel or fluid dispensing bottle
• Clean rags or shop towels
• Floor jack and jack stands (recommended)
• Wheel chocks
• Vehicle owner's manual for fluid type and reservoir location

Step-by-Step Bleeding Procedure

Step 1: Prepare the Vehicle

Park the vehicle on a flat, level surface and apply the parking brake. Place wheel chocks behind the rear tires for additional safety. Do not start the engine yet. Allow a hot engine to cool for at least 15 minutes before working near the power steering reservoir.

Step 2: Check the Fluid Level and Condition

Locate the power steering reservoir. Remove the cap and check the fluid level. If you are changing the power steering fluid and the fluid appears foamy, dark brown, or milky, drain and refill with fresh power steering fluid before proceeding. 

Step 3: Fill the Reservoir

Add fresh power steering fluid to the reservoir. Do not overfill, leave room for fluid expansion as it warms up during the bleeding process.

Step 4: Raise the Front Wheels

If possible, safely raise the front of the vehicle with a floor jack and support it on jack stands. Having the front wheels off the ground allows you to turn the steering wheel lock-to-lock without load, which accelerates air purging. If lifting is not possible, the procedure can still be performed with the wheels on the ground, it will just be harder to steer with no power assist with the engine off. Once the reservoir is full turn the steering wheel lock-to-lock atleast 10 times to get fluid flowing throughout the system. Be sure to top off fluid before starting the engine.

Step 5: Start the Engine and Begin Bleeding

Start the engine and let it idle. Slowly turn the steering wheel from full lock left to full lock right, holding at each end for 2–3 seconds. Repeat this lock-to-lock motion until the steering feels smooth and consistent.

Important: Keep an eye on the reservoir. If the fluid level drops significantly, stop the engine immediately and top off before continuing. Running the pump dry — even briefly — can cause serious damage.

Step 6: Monitor the Reservoir for Aeration

With the engine running at idle, look into the reservoir. You may see bubbles rising to the surface — this is normal and indicates air is being purged from the system. Continue the lock-to-lock cycling until bubbling stops or becomes minimal. Excessive foam that does not settle may indicate a suction-side leak in the hose or a loose fitting.

Step 7: Turn Off the Engine and Check Fluid Level

Turn off the engine and wait 2–3 minutes for the fluid to settle and any remaining bubbles to dissipate. Recheck the fluid level and top off with fresh power steering fluid as needed.

Step 8: Reinstall the Cap and Test Drive

Reinstall the reservoir cap securely and lower the vehicle if it was raised. Start the engine and take a short test drive, making several turns in both directions at low speed. After returning, recheck the fluid level one final time and top off if needed. Inspect the area around the reservoir, hoses, and pump for any signs of leakage.

Troubleshooting

Pump still whines after bleeding

Persistent noise typically indicates a suction-side air leak. Inspect all hose clamps and fittings on the low-pressure side of the pump. Also verify the fluid level is not being drawn down during operation, which would allow air to continuously enter the system.

Fluid appears foamy or milky and won't clear

Foam that does not clear after bleeding suggests air is continuously entering the system. Milky fluid can indicate water contamination. In either case, drain the system, identify and repair the source, then refill with fresh power steering fluid and repeat the bleed procedure.

Steering still feels heavy or stiff after bleeding

If stiffness persists, the pump may not be building adequate pressure. Check the drive belt tension and inspect the outlet hose for kinks or restriction. 

Ongoing Maintenance Tips

• Check fluid regularly: Inspect power steering fluid every oil change interval or approximately every 5,000 miles.
• Change fluid periodically: We reccomend changing the fluid in your power steering pump every couple of oil changes.
• Always use the correct fluid: We recommend dedicated power steering fluid for all of our pump assemblies to ensure maximum component life and seal integrity.
• Inspect hoses and connections: Cracked, soft, or swollen hoses are a leading cause of air ingestion and fluid loss. Replace hoses showing any signs of deterioration.