If you disconnect the drag link, then turn the wheels all the way one way, and then the other, do they turn any farther than with the steering all connected? If so then you need a longer or shorter drag link to get the steering wheel/gear box centered when the tires are pointed forward, or possibly a shorter pitman arm.
It's hard to describe how to figure it out, but if you sit and think about it for a little while you'll come up with a plan to see if your steering gear box and linkage is allowing full travel of the wheels.
Grigg
