1989 745 Turbo

Last night after some spirited driveling on the interstate, I noticed a noise while taking the first off ramp. When I got off the interstate and started taking lower speed turns I noticed it even more. The power steering is making a noise like it makes at the steering limits. I checked the fluid, and the level looked ok. Then I realized that the fluid was very frothy so I let it settle down. It was pretty low but there was still fluid in the reservoir. After topping it and trying to work any bubbles out of the system, the noise didn't get any better. When I stop the car, the now frothy fluid overflows out from around the reservoir cap. 20 year Volvo mechanic says he's never seen a system do this. Any ideas before I start throwing very expensive parts (like a new rack and pump) at it? I may try flushing the entire system with new fluid and see if this causes any improvement. If I can get another month of daily driving out of it before having the mechanic replace the rack (or better, being able to do it myself) then I'll be happy. If it turns out to be a bad hose/air bubbles in the lines I'll be even happier.

Randy Farmer
Marietta, Ga