98 Explorer Power steering

I have a groan when I turn my steering wheel to the left always and sometimes when I turn to the right. I took the top off the the power steering resevoir and when the groan is present there are bubbles in the fluid. I assume I have air in my system. Question- how do I tell where the air is coming from, is it the pump, the lines to the pump, the steering gear or rack and pinion?

I have a groan when I turn my steering wheel to the left always and sometimes when I turn to the right. I took the top off the the power steering resevoir and when the groan is present there are bubbles in the fluid. I assume I have air in my system. Question- how do I tell where the air is coming from, is it the pump, the lines to the pump, the steering gear or rack and pinion?


The system is under pressure from the pump into the rack. The pressure would make leaks there or in the rack obvious. The return line (from the power steering cooler if you have one) up to the pump is not under high pressure, but leaks here would drip p.s. fluid.

How many miles on your ex and how long since you changed p.s. fluid? Old fluid can "foam" or get air in it more easily than new fluid.

I would change to new fluid and see if that doesn't cure it.

Ford does have a procedure for bleeding the air out of a power steering system that involves putting a vacuum pump on the power steering pump resorvoir and putting a full vacuum on the reservoir for three minutes while the engine is running and turning the wheel slowly left and right. Do not hold the wheel at full stop right or left gor more than three to five seconds.

But I'd guess new fluid will set you straight.

Also noise check your tirods maybe a loose tirod can cause the grown