I too had a serious weaving back and forth on the road with my 46 half ton. Was pretty scary to drive especially whenever I ran across uneven road surfaces. Lucky for me the front end and kingpins were tight. All I did was adjust the sector gear on the steering box and the problem amazingly vanished!! The slop in the steering wheel also was eliminated. I also filled the steering box with fresh grease since I could see after removing the lubrication plug that it was low. It now steers much easier.
