How to Purge Air From Your Power Steering System

Whether you’re hooking up a system for the first time, reinstalling a pump or steering gear, or simply changing fluids after a race weekend, it is important to ensure that there is the least amount of air in your system before you fire the engine. Here’s how to easily complete a purge procedure.

1. Lift the front of the vehicle off the ground, just enough for the tires to clear. This will make the process much less strenuous.
2. Fill up your power steering reservoir with fluid to the normal fill line.
3. Without starting the engine, cycle your steering wheel from lock-to-lock around 30 times, turning slowly and smoothly. This is manually push fluid through the system and will start to purge any air that has been trapped in the pump/hoses/etc.
4. After these 30 cycles, check your reservoir. If there was air in the system, it’s likely that your fluid levels dropped a little. Add fluid to your preferred fill level if necessary.
5. Drop the front of the vehicle. Fire the engine. Go drive.

Easy as that.

Extra Tip: if you’re still getting air into the fluid after you’ve gone through this process, it is more than likely something in your system is causing this, and purging isn’t actually fixing the root cause. Often, aeration/cavitation will make the pump whine. Poor reservoir design is one of the most common sources of cavitation, but it is possible to get air leaks at hose connections or reservoir connections.