I just had an 850 power steering system take me to school the other day. After replacing the rack twice and the pump once I finall figured out that it was a seizing U-joint in the column. The u-joint is hidden under a rubber boot right at the firewall. If the pump appears to be moving fluid and you can hear it groan when you turn it to lock position then it is probably ok. The racks do go bad in these cars but it is few and far between. Drop the driver's kick panel, pull up the boot, remove the bolt that goes through the coupler and slide it up the column. Now see what kind of play you have in that u-joint. It should wobble all the way around on it's axis. The one I had was frozen on one axis. When the car first came in it simply seemed stiff all the way around, as the problem progressed it got to where it was ok in spots and stiff in spots. This was because when it came up against the frozen axis it would be stiff and when it was using the other axis that was not frozen then it was fine. The P/S system is real basic, it has a pump, a rack, the hoses that join them, and the column. So long as you have nothing else in the front suspension binding like strut bearing plates or anything along those lines.

Mark