2008 Taurus Limited has a leak at the high pressure power steering line and rack and pinion connection. I have replaced hose and O-rings and it still leaks out after driving it awhile. it may go 30 miles and then start leaking. When it starts to leak, it will leak while running and while sitting. I have tried using an O-ring with a bigger wall thickness and it still will leak. Any suggestions on the root cause? Thank you in advance.