not 100% of the setup on an av - but assuming it's very similar to that of a 48 super a ...
AND assuming you're talking about a FRONT wheel...
the steering slop comes from many places you'll need to work on.
The wheel bearing is an obvious point.
then up from there - the steering linkage is connected to the spindle with a bolt that has a sort of cone end on it (inside). take that bolt out and make sure it's not broken - clean it - and make sure it goes back in tightly - loosen the jam nut so you're not tightening against THAT - tighten it - then do the jam nut.
From there - each linkage in the steering arms has adjustable ball sockets. look into the ends and you'll see they're slotted and can be tightened with a large screwdriver - but also held in place by a cotter pin most likely. pull the pins if need be and tighten the socket (try removing one to see what it does if you haven't seen them before) but be sure they're all nice and tight when done.
finally - the arm that comes off the steering box (from below) is a "known" weakness on these tractors.
try to either look in from the front, or up from the bottom while somebody wiggles the steering wheel back and forth. You'll probably notice some slop in there - you'll see the shaft turn before the arm turns. (the arm will be loose).
you MAY be able to sneak a wrench in there from below and actually tighten it up to remove some slop - worth a try but can be tedious.
Do all that and I'm pretty sure you'll get rid of the wobble.
May or may not need to go further to remove looseness from the steering wheel (amount you have to turn the wheel before the tires start moving) - as in rebuild the box.