gear box and coupling question

first I would make sure it's the box, disconnect the pitman arm and make sure the wheels turn free Right to left, if not you might have a ball joint binding or the idler arm, if it's the power steering box, the only thing you can adjust is the sector shaft. there is a 3/16 allen with a 5/8 nut on top loosen the nut and back out the screw 1 full turn and tighten the nut and see if it is better.