Power steering, back pressure on high side

My power steering pump is whining slightly even standing still and loudly when I turn. That just started. I checked the pump out and there is also a large difference in fluid level between on and off. To get the power steering to work at all the fluid level must be at least just above the rotating parts inside. But when I shut the engine off the level goes to the very top of the resivour. (any more just squirts out). I was told I probably had blockage in my high pressure line so I disconnected both sides and blew it out with compressed air. After blowing out the fluid, the air blew through this no back pressure. I reconnected the line and the problem continues. I also noticed that when I removed the high line from the pump that only a VERY slow leak dripped out of the pump as I was blowing the line out. Is that normal or could the blockage be in the pump. What else could be causing the back pressure.

I have the same problem. does anybody know if it is the pump or the rack making it squirt out because it gets a ton of air in the system
thanks
Todd

I have the same problem. does anybody know if it is the pump or the rack making it squirt out because it gets a ton of air in the system
thanks
Todd
I also have the same problem on a 1999 Sable.

I got my problem fixed but hate to say is was the most expensive part of the system...The steering rack had to be replaced. The dust boots on the tie rods comming out of the rack were so full of oil they looked like baloons because the rack seals were leaking. Each time the steering moved back and forth oil would seep out and ofcourse suck air in. Anyways I bought a remanufatured rack for 400 installed it and now works fine.
c-ya
ToddG