I agree with rfs56trk. What happens is the worm gear in the box wears more in the general area of the straight ahead position, because that's the direction where the truck is driven the most. As a result, when you get a proper adjustment in the straight ahead position, then it binds in the turning positions (left or right) because those are the areas where the wear is not as much. As a result, you cannot really adjust for a lot of wear.
