my father-in-laws suzuki has some steering play, is there any way to adjust it, to give it tighter steering without changing anything. I heard that the nut on top adjusts is this true. Any hepl would be great!

The adjustment nut is on top of the steering box, but take a look at the other parts first. The box is the last stop when diagnosing extra steering play.
First - check the rag joint on the steering column (under the hood, just before the steering box).
Second - Jack up the front end so the tires are off the ground and then have someone else move the tires left to right and back again. Check the tie rod ends on the tie rod and drag link. Watch for wiggle... there should be none.
Third - Take a look at the pitman arm (connects the drag link to the steering box. See if there is any 'wiggle' there when turning the wheels.

If you go to the steering box first, you may overtighten the gears without fixing the problem, and that could get ugly if they failed in a turn on the road at speed.
<img src="/forums/images/graemlins/cheers.gif" alt="" />