There is some play in steering wheel (precisely in steering gear box) and I have power steering. Its saginaw unit, and I've found that it has some adjusting screw on top of it and that by adjusting that screw I can reduce play. On the other hand, I've read that this should be done only after rebuilding complete unit and that adjusting it without rebuild could make elements inside bind and damage the unit. Can it be done or I need to rebuild it first? It has some 180.000 miles on it and no visible leaks on it nor on ps pump.