2001 Toyota Celica power rack

I recently had a leak on the Rack and pinon I payed a friend to replace it he ordered the rack from toyota installed it refilled resivoir power steering worked about two minutes long enough to get it out of the Garage. Then it quit he reinstalled another rack same thing we are all stumped even toyota. The first thought was the pump, we changed it with a used one and the same thing happened it worked for a minute then quit we have tryed working it back and forth but still nothing on occasion it acts like it wants to work.