If you have this type of steering box it may not be a major job. When you turn the steering wheel in the play does it appear to screw up and down?
If so then the majority of the problem is likely to be in the top bearing and may well be adjustable. It will be necessary to remove the steering wheel. A suitable three-legged puller is ideal but it may be necessary to cut the wheel off with an angle grinder as sometimes even a heavy puller will not work.
Once you have the wheel off remove the chrome cover and you will see the top nut (81) retained by a tabwasher. Remove the tab and nut. A shallow spanner is necessary to hold the bottom nut and this can be made from a piece of 1/4" plate. Remove the lower nut and inspect for a wear track from the ball bearings. Remove the balls using a magnetic pointer if possible. Remove the bearing (76) and again inspect for wear. DO NOT AT ANY TIME SCREW THE STEERING COLUMN ANTICLOCKWISE. Component parts or a bearing kit are available. Fit the new kit and screw down the nut (79) Fit the tab and top nut.
Slowly take up the lower nut until the play disappears. Lightly nip up the top nut. Jack up the front of the tractor to take most of the weight off the wheels. Turn the steering back and forth. It should be free and without any drag but not loose. Tighten the upper nut. If it shows any drag you will have to loosen the lower nut slightly and check again when the top nut is tight.
Wear in the rocker shafts (52+17) will normally produce a wheel shimmy not steering play. Check your ball joints as well.
DavidP, South Wales