I changed out a PS pump on a 06 Taurus about a year ago when it started blowing out fluid. Spun the old pump and heard a noise that didn't quite sound right. So I bough a new pump and put it and bled the system like I read about and watched on You Tube with out luck.
I researched these pumps Ford used and found all kinds of issues regarding air. Took forever to get the air out manually or so I thought. About a year later, it started blowing out fluid again.
So I tried to manually purge air out again with no luck at all this go around.
By the way, checked for leaks and found none on both occasions. Kind of a pain with rack and pinion.
So I took my brake bleeder (Hand Vacuum Pump w/Reservoir) and applied vacuum to the reservoir. A couple of old school mechanics said it was the best and most effect way to deal with this problem when I researched it. If you had a leak in the system, it would not hold vacuum. If you had air trapped, it would pull it out (burping). If air was suspended in the fluid, it would draw it out.
Pumped it up to about 15 HG (no more) and left it until it BURPED (about five minutes later). Did this over and over again (about three times) until fluid was being drawn up the vacuum tub (clear vinyl) towards the vacuum reservoir without air bubbles suspended in the fluid. Each time vacuum draw was easier and fluid moved faster up the vacuum tube. The sign of no more suspended air!
There is no need, nor do you want to pull fluid into the vacuum reservoir due to the size of the reservoir (you'll pull it right into the hand pump). You want to keep that volume available in case it burps fluid and air out.
Started it up and no more fluid blowing out the top. The whining is all but gone, unless you turn it hard to one side which is normal.
These pumps are pain in the backside if you get air trapped within the system or suspended in the fluid.
I cannot tell you how beneficial it has been to have an assortment of rubber stoppers w/hole and a manual vacuum pump when it comes to bleeding air out of reservoir systems.
I purchased several size rubber stoppers with holes in the center at widgetco.com a couple of years ago for this reason.
http://www.widgetco.com/epdm-rubber-stoppers