Any suggestions on why my power steering pump continues to fail. Ford has replaced 4 pumps in 4 years. Once installed the pump starts to whine after about 6000 miles. Between 8-10000 miles the pump fails. Ford has replaced some of the lines thinking there might be a restriction but it has not helped. Unfortunatly the truck is now off of warranty and it's happened again. Of course Ford now says I have to foot the bill for repair even though it's been an ongoing and documented problem.