If you turn the wheel all the way to the left, or as far as it will go, does it turn smooth all the way to the right? Once at the far right, does it turn hard the whole time to the far left?
I would unhook the right tie-rod and see if its one side or the other, if that didn't tell me anything I would unhook the draglink off the pitman arm. Check each wheel separate, then the gear box.
Is it a power steering box or manual? Manual boxes are easy to work on and understand. The power steering unit is a little harder to work on due to the valves and moving parts. In eather case, you might want to get that liquid wrench out and start soaking down all the bolts and joints.
King pins normally are stiff in both directions, draglink ends and tie-rods will loosen up as they wear. The grease can get stiff and gummy if it has set for awhile. With the wheels off the ground and the gear box unhooked, the wheels should turn left and right pretty easy. You should have no movement up or down on any of the joints. Each steering joint should be tight and free to twist and turn. Use plenty of grease.
Let us know what you find out, Joe.
