2001 Oldsmobile Intrigue Hard to turn steering wheel

My auto mechanic has attemped to correct my power steering problem but the hard steering problem persists. (Only partly corrected) He has replaced the rack and pinion, also the pressure line from the pump to the rack and pinion and installed new tie rod ends. All parts are new but of course after market. The wheels have been aleighned. The pump has not been replaced in that it was working OK when the work was started. The reason for the work was to correct noise when steering and very slight leak in the pressure hose coupling. Is there anything (exceptthe pump) that we have overlooked? Larryh