Have any of you had an issue of power steering resevoirs failing? I have a persistent fluid leak. The rack is in tip top shape...I recently replaced both boots and there is no issue of leakage there. the lines do have some fluid on them, but mostly near the top ends. the top of the resevoir is however coated in fluid. I cleaned the resevoir up a bit, toped it off with lucas brand stop leak fluid (which did slow the leak a bit) and still the leak persists. It seems to be minimal at city speeds, but crank her up to 75mph on the highway and 15-20 minutes later the pump begins to groan a bit and the steering wheel vibrates when turning. The resevoir has never been dry, but it has run low enough so that the end of the dip stick can't reach the fluid. I was thinking about making up a rubber gasket to help seal the cap to the resevoir...is this a common issue? is there pressure in the resevoir at speed? please advise