Yep! I can think of a few things that could attribute to that issue when overhauling that box.
1) The ball nut on the steering shaft was not installed equidistant to the sector shaft gearing. If you are "off mesh" one gear, you will have more or less turning circle in one direction as the ball nut runs out of "travel" and contacts the underside of the steering column.
>> I am pretty sure I got that one right.
2) There is no end play on the sector shaft end, where the adjustable tension nut is. Back it off a 1/2 turn and see if it improves the steering feel and response.
>> Would not this have showed up right away -- steering was pretty good initially. Steering wheel pre-travel has become very large after the first few hours since repair.
3) The pitman arm and the end of the steering shaft are marked with a "scribed" line, as in the picture I've attached. They need to be lined up when you re-install the pitman arm. This "times" the box in relation to the pitman arm, so when the ball nut is centered, the pitman arm is also sitting in the middle of it's range of travel.
>>will have to check that one
4) And only I'm only adding #4 to this list, because I've been there and done that! The lower radial bearing fell out of place/off the end of the steering shaft during installation, and when you tightened down the 4 bolts holding the steering tube to the box, you crushed that bearing.
>>Possible -- but would that also have shown up right away?
Thanks again