Looking for solution to my audi 80 1994 power steering problems. The pump is rejecting fluid .?

I recently changed the rack due to fluid leakage. I have also changed the pump. The fluid comes out from the covered pot with very high pressure, empties fast and the steering goes hard after this action. The local mechanics are finding it difficult to diagnose the problem as they still insist that the rack and the pump are good. No leakage from the pipes. Please what could be wrong?Looking for solution to my audi 80 1994 power steering problems. The pump is rejecting fluid .?Try bleeding the system - you might have an air lock