I have replaced the power steering pump on my Windstar atleast 4 different times in the last 6 months. I have also replaced the rack-n-pinion part of the steering too. The pump just went bad again. It will be going fine,then it just quits. Could there be something in the power steering fluid that is killing the pumps or just a bad batch of pumps.
I’ve seen lots of pumps going bad on this vehicle because of air getting into the system. Usualy the air gets into the system near the P/S reservoir, or around the rubber hoses. Other times, not doing the proper bleeding of the system after replacing steering components, leaves behind some air traped in the system, and with time the pump goes bad. Good luck.