How to Get Air Out of a Power Steering System Without a Vacuum Pump

You can purge air from most hydraulic power-steering systems without a vacuum pump by safely lifting the front wheels, filling the reservoir, turning the steering wheel slowly lock-to-lock with the engine off and then on, and topping up until bubbles and noise disappear; persistent aeration usually means a leak on the suction side that must be fixed. This article explains why air gets in, what you’ll need, step-by-step bleeding methods, and how to troubleshoot stubborn noise or foaming.

Know Your System First

Before you begin, confirm whether your vehicle has a conventional hydraulic power-steering system, an electro-hydraulic pump, or full electric power steering (EPS). Traditional hydraulic and electro-hydraulic systems use fluid you can bleed; EPS has no steering fluid and cannot be “bled.” Always use the fluid type specified by the manufacturer (some require dedicated power-steering fluid; others specify ATF such as Dexron III/VI)—mixing the wrong fluid can damage seals and pumps.

Why Air Enters Power Steering—and What It Feels Like

Air typically enters through loose clamps or cracked low-pressure return hoses, a pump shaft seal, or during component replacement. Symptoms include whining or groaning that changes with steering input, jerky assist, and foamy or milky fluid in the reservoir. If noise persists after bleeding, suspect a small leak—especially on the suction side, where air can be drawn in without fluid visibly leaking out.

What You’ll Need

The following items help you bleed the system cleanly and avoid introducing more air or debris.

• Correct power-steering fluid (per owner’s manual or service information)
• Floor jack and jack stands (or a lift) to raise and support the front axle
• Wheel chocks and safety gear (gloves, eye protection)
• Funnel, rags, and a drain pan
• Clear vinyl hose and a catch bottle (for return-line bleed/flush method)
• Basic hand tools to access clamps/hoses (and torque specs if loosening lines)

Having the right tools and fluid on hand minimizes downtime and reduces the risk of running the pump dry during the procedure.

Primary Method: Manual Bleed Without a Vacuum Pump

This is the safest, most widely applicable method recommended by many manufacturers for purging air after hose, pump, or rack service.

1. Cold start conditions: With the engine off and the front wheels off the ground, set the parking brake and chock the rear wheels. Ensure the reservoir and surrounding area are clean to prevent contamination.
2. Fill the reservoir: Add fluid to the “COLD” or “MIN” mark. Leave the cap off and keep the fluid handy.
3. Engine off cycling: Slowly turn the steering wheel from full left lock to full right lock 20–30 times. Do not force the wheel against the stops; just reach them and reverse. Watch the reservoir and keep topping up to prevent the pump from ingesting air later.
4. Rest and de-aerate: Let the vehicle sit 10–15 minutes so trapped microbubbles can rise out of the fluid.
5. Engine on cycling: Start the engine and let it idle. Slowly turn lock-to-lock 5–10 times. Avoid holding the wheel at full lock for more than 2–3 seconds to prevent over-pressurizing the pump and hoses. If the fluid turns foamy, shut off the engine and wait another 10–20 minutes.
6. Stabilize and recheck: When bubbles disappear and assist feels smooth, lower the vehicle, road test with gentle steering inputs, then recheck fluid level and appearance. Top off to the correct HOT mark after a short drive if specified by the manufacturer.

When this process is successful, you’ll see clear fluid without foam, a steady level in the reservoir (no constant burping), quiet operation, and consistent assist throughout the steering range.

Alternative Methods When Air Is Stubborn

Return-Line “Bleed/Flush” Method

If air pockets persist, a controlled return-line bleed can move bubbles out more effectively. Use care to avoid running the pump dry.

1. Identify the low-pressure return hose at the reservoir. Remove it from the reservoir nipple, cap or plug the reservoir nipple, and route the hose into a clear bottle.
2. Fill the reservoir to the brim. With an assistant ready to add fluid continuously, start the engine for just 1–3 seconds while fresh fluid is poured in and old fluid/air exits into the bottle. Shut off immediately if the reservoir level drops.
3. Repeat short bursts until the return flow shows no bubbles and fluid runs clear. Never allow the reservoir to run low.
4. Reconnect the return hose, secure clamps, top off the reservoir, and perform the manual bleed steps (engine off cycles, rest, engine on cycles) to finish.

This method both purges air and refreshes old fluid but requires coordination to prevent cavitation. It’s especially helpful after replacing a rack or pump with significant trapped air.

Cracking a High-Point Fitting (Advanced/Only If Specified)

Some technicians briefly loosen a high-point line or banjo bolt to vent trapped air. This is messy and can be hazardous. Only attempt if your service manual allows it, you have torque specs, and you can contain fluid safely.

1. With the engine idling and an assistant turning the wheel slowly, slightly loosen the designated high-point fitting just until fluid (and air) seeps, then retighten when a solid stream appears.
2. Clean the area, torque to spec, and recheck for leaks. Finish with the manual bleed routine.

Because of fire risk, environmental concerns, and the chance of under- or over-torquing fittings, use this method sparingly and by the book.

Special Cases and Notes

Electro-hydraulic systems bleed the same way as conventional hydraulic setups but may specify key-on/pump-running cycles. EPS (full electric assist) has no fluid to bleed; noise or stiffness requires electrical/diagnostic checks. Vehicles with hydro-boost brakes (common on certain trucks) share power-steering fluid; after bleeding the steering, you may need to slowly pump the brake pedal with engine off, then on, to purge the booster per the manufacturer’s procedure.

Troubleshooting Persistent Noise or Foam

Use these checks if you cannot clear the air or the system gets noisy again soon after bleeding.

• Inspect the suction side: The low-pressure hose from reservoir to pump is the most common source of air ingress. Look for hardened hoses, loose clamps, or hairline cracks. Replace suspect hoses and use quality clamps.
• Check the reservoir: Some have internal strainers or O-rings that harden and allow aeration. A cracked or contaminated reservoir can reintroduce bubbles.
• Pump condition: A worn pump can cavitate and aerate fluid even without external leaks. Whine that tracks engine speed and persists after proper bleeding may indicate internal wear.
• Rack and lines: After major component replacement, residual air pockets can be stubborn; repeat the manual bleed after an overnight sit. If fluid turns milky repeatedly, pressure-test and dye-trace the system for microleaks.
• Fluid type and level: Wrong fluid or overfilled reservoirs can cause foaming. Correct any mismatch and aim for the mark specified for hot or cold checks.

Resolving the root cause—usually a minor leak or degraded component—prevents recurring aeration and protects the pump from damage.

Safety, Technique, and Environmental Tips

Bleeding power steering is straightforward, but a few habits protect you and the vehicle.

• Never hold the steering at full lock longer than 2–3 seconds; heat and pressure spike quickly.
• Keep the reservoir from running low at all times to avoid cavitation, which can scar the pump.
• Always support the vehicle securely with jack stands on solid ground; never rely solely on a jack.
• Clean spills immediately; power-steering fluid is slippery and flammable. Dispose of used fluid at a recycling center—don’t pour it down drains.
• If you loosen any fittings, use correct torque values and replace crush washers where applicable.

Good preparation and disciplined steps reduce mess, prevent pump damage, and yield a quiet, consistent steering feel.

Summary

You can remove air from a hydraulic power-steering system without a vacuum pump by elevating the front wheels, filling with the correct fluid, slowly cycling the wheel lock-to-lock with the engine off and then on, and allowing time for de-aeration between cycles. If bubbles persist, a controlled return-line bleed helps, but continual foaming or noise points to leaks—often on the suction side—or worn components. Verify system type, use the correct fluid, avoid holding full lock, and recheck levels after a short drive for a lasting, quiet fix.

How long does it take to get air bubbles out of power steering?

Getting air out of the power steering system can take from a few minutes to an hour or more, depending on the method and vehicle complexity. For most cars, turning the steering wheel lock-to-lock multiple times with the engine running and the fluid reservoir full will remove air in about 2-5 minutes. A thorough process with a vacuum pump may take longer, especially for systems with intricate components. 
Quick Bleeding Method (2-5 minutes)

1. Fill: the power steering reservoir to the proper level. 
2. Start: the engine and let it run at idle. 
3. Raise: the front wheels off the ground so they can turn freely. 
4. Turn: the steering wheel slowly from full left to full right and back, several times. 
5. Check: the fluid level and add fluid if it drops. 
6. Repeat: the lock-to-lock turns until fluid foaming or rushing sounds dissipate. 

Vacuum Bleeding Method (Longer Process)
If the quick method doesn’t work, or for intricate systems, a vacuum bleed is more effective. 

1. Apply 15-18 inches of vacuum to the reservoir using a vacuum pump and a modified cap or stopper.
2. With the reservoir under vacuum, turn the steering wheel from lock to lock for about 5 minutes with the engine running.
3. Recheck and top off the fluid level as needed, as it may drop significantly during the vacuum bleeding.

Key Tips

• Watch the fluid: Look for foaming or bubbles in the reservoir, which indicate air is escaping. 
• Check the fluid level: Always keep the reservoir topped off to the proper level. 
• Avoid holding at the stops: When turning the wheel, don’t hold it at the lock for too long, as this can cause the pump to work harder and introduce more air. 
• Consider test drive: After a successful bleed, take the vehicle for a short test drive and recheck the fluid level afterward. 

How to bleed air out of power steering pump without?

To bleed air without a vacuum pump, start by topping off the power steering fluid reservoir. With the engine off, turn the steering wheel fully left and right several times slowly to help move trapped air. Then, start the engine and repeat the process while monitoring fluid levels, adding more if needed.

How do you vacuum air out of power steering?

Here. It’s not going to hold vacuum. So we always want to check our line in our tool. And make sure it’s in good shape.

How to get trapped air out of power steering?

To remove air from a power steering system, fill the reservoir, lift the front wheels off the ground, start the engine, and slowly turn the steering wheel from full left to full right about 15-20 times while keeping the fluid topped off. Do not hold the wheel at the stops. Shut off the engine, recheck the fluid level, and repeat the process until the fluid level remains stable and the system is no longer noisy.
 
Tools and Materials

• New power steering fluid
• Jack and jack stands
• Wheel chocks
• Vacuum pump (optional, for stubborn cases)
• Liquid vapor separator (optional)

Step-by-Step Guide

1. Fill the reservoir: With the engine off, fill the power steering reservoir to the correct level. 
2. Lift the vehicle: Use a jack to lift the front of the vehicle, ensuring the front wheels are off the ground. Place jack stands for safety and then position wheel chocks at the rear wheels. 
3. Start the engine: Start the engine and let it idle. 
4. Turn the steering wheel: Slowly turn the steering wheel from the full left position to the full right position and back again, repeating the movement 15 to 20 times. 
5. Check and refill the fluid: As you turn the wheel, the fluid level will drop; add fluid as needed to prevent new air from entering the system. Do not let the level get too low. 
6. Listen for noise: You may hear gurgling sounds as the air is pushed out of the system. 
7. Repeat if necessary: If the system is still making noise or the fluid level continues to fluctuate, repeat the process. 
8. Final check: Once the fluid level is stable and the noises cease, shut off the engine and recheck the fluid level one last time. 

If Air Persists

• Vacuum bleeding: Opens in new tabFor systems with stubborn air, a vacuum pump can be attached to the reservoir to draw air out while the engine idles. 
• Check for leaks: Opens in new tabCheck for any external leaks, as an external leak can introduce air into the system. 

This video demonstrates the process of bleeding air from the power steering system: 57sCARDONE IndustriesYouTube · Nov 21, 2014
Important Considerations

• Safety: Always use jack stands to support the vehicle, never relying solely on a jack. 
• Fluid type: Use the correct type of power steering fluid specified in your vehicle’s owner’s manual to avoid damage. 
• Do not overfill: Overfilling the reservoir can cause fluid to spew out. 
• Avoid holding the wheel at stops: Turning the wheel to the full lock position for extended periods can put excessive strain on the power steering system.