I am new to the forums but have owner my H1 since fall of 2015. Over time I noticed the steering getting sloppy and wandering occasionally. With someone moving the wheel while I was underneath the truck, I noticed that there was a lot of play in the original steering gearbox where the lower shaft enters the bottom of the unit. I bought a new box on eBay this fall, installed it and in some ways it feels tighter, but now the steering wheel can freely travel from about 12 o’clock to 6 or 7 o’clock without any effort. You can see the column turning freely before the lower shaft moves the pitman arm. I have verified that the column and pitman arm were attached in the correct positions and can’t seem to find anything obvious that would explain the play. Would this possibly be fixed by adjusting the preload?

 

Here is the procedure that GM Saginaw Division recommends to adjust the steering box.

Disconnect the pitman arm from the sector shaft, completely back off the sector shaft adjusting screw on the sector shaft cover.

Center steering on the "high point" then attach an inch lb torque wrench to the steering wheel shaft, the torque required to keep the shaft moving for one complete turn should be 1/2 - 2 in lbs.

If the torque is not within these limits, loosen the thrust bearing locknut or tighten valve sleeve adjuster plug to bring the preload within limits.

Tighten the thrust bearing locknut and recheck preload.
Slowly rotate the steering shaft several times, then center the steering on high point.

Now, turn the sector shaft adjusting screw until a steering shaft torque of 3 - 6 in lbs more is required to move the worm through the center point.

Tighten the sector shaft locknut to 35 ft lbs and recheck the sector mesh adjustment.

Total steering gear preload should be 14 in lbs or less.

Install the pitman arm and replace back in vehicle.

NOTE: To try and adjust the sector shaft screw without doing the preceding will DAMAGE the steering gear.
Most of the play is not in the sector shaft adjustment, it is the spool valve area.