When you say the P/S is shot, what is it doing? If your getting no power assist it is more likley the rack. If you want to go manual rack, but not the actuall rack yet, I would pull the pump and drain as much fluid out of the rack as possible so you won't have to push the fluid in the rack. If the rack is still good, running it w/o fluid might eventually wear it out since the fluid does lube it.