I`m afraid that looks like its in the box and not the coupling as I thought you were describing, mainly because the slop is after the coupling. Have a little gander at a Bentley on how to adjust and you may have some succes just with adjustment. Ozziedog,,,,,,,,,,,,,,don`t go too tight.
What I did not long ago. Directly on top of the steering box is a rubber dust cover with a little arrow on it, this should face the notch that's cast on the upper rear part of the steering box when the wheels are straight. Jack the front tyres off the floor and turn Steering wheel from left lock to right lock to find the mid point. When the the wheels are straight and the gearbox is centralized you shouldn't have any play in the Pittman arm coming out of the box. To check this I removed the arm going to the beam to feel for play in the pitman arm. If you have play here use the adjustment screw so the play goes. Don't go mad just enough that the play goes away, you can get a tool for this for accuracy. Its normal to have some play in the Pittman arm when the wheels are not straight so don't worry about that. If that doesn't work and you have checked everything else you may be looking at a steering box refurb.
I took your original post to mean 2 inches of play at the wheel which isn`t out of order to be honest but that much play at the steering box is BAD !! They can be adjusted with the screw and locknut , i think Haynes give guidance but i think , looking at the vid there`s too much play to adjust out so might be replacement time ....
That sounds like perhaps like an Early box where the bushings are replaceable as they are basically similar to the Split Screen versions. The later boxes have the bushings cast in , so without machine shop time you will not be able to do more than replace oil seals etc. If the Schofields guy can do all the box types, its great there is a way out.
Just saw the video, you can see the steering arm shaft rocking.. The adjustment can take out some of the rotation slop by pushing the shaft further into the mechanism, but if the end of the shaft has ovaled the bushing then its machine shop time. (which is what happens if you over tighten it or drive with idiot wide tyres)
