Air in power steering system

[MorganMcCann]

I recently rebuilt 3/4th of my front end, and when I did the brakes I turned the wheel with out the engine on. I read on a forum somewhere that doing that will put air into the lines. When I went over a series of bumps, the whole front end would shake. I went to a parking lot, went in circles at full lock for about 2 minutes and after that, it worked fine.

What caused that to happen?

When I did my front end I didn't touch any power steering stuff. I did brakes, a body mount, sway bar links and bushings, shocks (all 4) and about 5 months ago my ball joints were done.

 

[adsm08]

Turning the wheel with the engine off can cavitate the fluid. It will cause steering vibrations until it gets worked out.

 

[MorganMcCann]

Turning the wheel with the engine off can cavitate the fluid. It will cause steering vibrations until it gets worked out.

But how does that occur?

 

[036speed]

Because you are making the fluid move with out the pump spinning.

 

[adsm08]

The system is designed to not work without the fluid being under pressure. When you move the power valve without the fluid being under pressure and moving it cavitates it. It doesn't happen with the fluid under pressure.