check the new and old bearing on the sector shaft for play, also once the bearing is back into the housing, before installing the pitman seal, install the sector shaft with the back housing. sinch down the 4 bolts and snug the adjusting nut. then check the side to side play. sadly this tiny amount of movement equates to a lot of slop in the steering.
there is a preload procedure that Ferm posted here in the forum on how to set it all up. in involves setting the input shaft before setting the sector shaft preload. the way I did it was by locking the housing down in a vice, then once the input shaft was set, place the pitman arm on the box and snug up the big nut. make slight adjustments on the sector shaft while moving the pitman arm back in fourth feeling the lash in the gears. once I could not feel any lash, rotate the input shaft lock to lock several times while using your hand on the pitman arm to give a little resistance. re-center the box and double check the feel of lash. I would get it to the point I could not feel any lash when centered but there was no resistance when spinning the input shaft. if you start to feel resistance turning the input shaft, back off the sector shaft adjustment.
it's almost like setting up a ring and pinion but with much tighter tolerances.
when assembling the box, the most challenging part is getting the BB's in to place properly, on my first go-round I goofed and somehow ended up getting one of the bb's past the keeper where it worked it's way down the worm gear into the bottom of the piston cavity which caused the box to bind up while out on a trip to the beach! luckily I was able to drive it back home where I pulled it and discovered what had happened.