The steering is a chain of moving parts, any looseness in any part all add up to the total looseness in the entire steering system (or chain if you will).
Put the front of the vehicle in the air on jackstands, with front axle hanging free. Check for wear on all the steering parts, push/pull/lift/drag/twist, replace the worn parts, that will tighten up the steering. As well, check the steering box, its wears and creates lash in the steering as well.
Another test is to have someone turn the steering wheel back and forth, as you watch each joint, look for looseness (lash) in the joint. i.e. the link on one side moves a fraction of inch before the link on the other side starts to move. Do the same for the steering box, i.e. the pitman arms moves at the same time the steering wheel shaft moves.
There is an adjustment for pre-load on worm gear of the recirculating ball steering box, thats not really for wear, its for adjusting during assembly, but adjusting it in a worn steering box can tighten it up a little. Adjusting that pre-load, when its not needed or over tightening it will destroy your steering box, so make sure there is some lash in the steering box and don't over-do it.
