Adjust it with steering in centre (road wheels straight ahead) and then go lock to lock to check for any tightness (front end should be blocked up with wheels off the ground of course.
unquote
I suggest you DO NOT adjust it in the centre position, because it may very well get VERY tight on lock to one or both sides, even to the extent of causing damage due to the huge power of the power-steering ram.
Do all the following with the engine STOPPED.
Better plan is to jack the wheels clear of the ground. Turn full lock one way, THEN adjust the hex-socket nut down gently snug, and tighten the locknut.
Now gently steer to dead-ahead, and then to full lock the other way.
If at any stage it feels tight, or has a sensation of binding, STOP, and slacken the hex-screw a tad.
If / when it feels good, take it out for a careful try-out. Nudge the hex-screw in a tiny bit at a time till it's as good as it can be but NOT BINDING when the wheels are up, engine stopped.
Take the opportunity to check steering box oil level.
CharlesY