I have a '90 F-150 with power steering and am wondering if anyone can give me some insight on how to adjust the steering box. I have too much "play" in the steering wheel, and all the tire-rods and steering components are in good shape.

 

I just did the same thing. Lossen the lock nut on top of the box and turn the adjuster clockwise 1/8 turn and tighten back up the locknut. Go for a drive and see if you like it. Adjust more or less till you find the way that handles the best.