power steering box leaking from plates on top

If the leak is in the control valve, and you plan on pulling that part to replace the O rings, mark it's exact location so you can return it there for your initial start up. That valve is adjustable as mentioned by Dave999. Just a tiny adjustment can have dramatic results. That valve needs to be centered exactly so steering effort is the same going to the right or left. Basically, if it gets out of whack and needs to be centered, you need to loosen the two bolts SLIGHTLY so that you can tap the valve housing toward the front or rear to where there is no power assist turning the wheel either direction. This is done with the engine running, front wheels off the ground, and fluid in the system, so, if you loosen the valve too much, you will have power steering fluid all over the place. Too tight and the valve won't move. Marking the valve location before you take it off gives you a good starting point, and sometimes it won't need to be adjusted at all. If the leak is around the input shaft, that's a totally different problem and procedure. You may want to look in the FSM to follow the steps needed for either leak repair.