Steering is not the easiest to adjust or trouble check. More poor steering adjustments are made by owners, rather than any great steering improvement. All newbies wanna make lots of changes. Buses are big equipment that are made of big parts that last a very long time. The action that makes any steering adjustment needed is the total lack of lubrication. About every bus I have worked on has nearly no steering box grease. The new good stuff being synthetic 90Wt. I've been using some 50 WT synthetic with great success.
Before making any changes to the steering, look the complete system over for any obvious looseness and any connections that are stiff.
One very important part of the steering is the front wheels toe in setting. If this is not set or adjusted properly, many conditions will be created. The worst condition will be tire wear.
Any big tire shop will check the tires condition and advise of any conditions noticed. Before any steering box adjustments are done, check the grease level first. The box adjustment is fairly easy. If the vehicle is a large unit with no power steering, raise the front tires just off the pavement. Sit at drivers seat and aim front wheels in a straight ahead position. Grasp steering wheel at the tor of wheel and notice any free play/movement. Go to steering box and look for the adjustment bolt. The adjuster will be recognise by a large bolt with a jamb nut. Some times the jamb nut will be very tight and require some large wrench or socket. While holding the adjusting bolt, the jamb nut is loosened without mooving the adjusting bolt. The adjusting bolt may have a common slot or an allen type drive. Have a helper sit in driver's seat. Talk to helper to move steering wheel very gently left and right and notice any free play. While helper turns steering wheel, left and right, slowly and carefully tighted adjuster. The adjuster bolt will slowly get harder to turn. When helper tells all free play is gone, stop tightening bolt and snug down the jamb nut while holding the adjusting bolt. Go to steering wheel and test for zero free play. Tighten the jamb nut more tightly but not too tightly. Frank