Not really rocket science this bit.
There is a control valve at the back of the steering box, where it attaches to the inside of the engine bay. The sealing cap on mine was pretty rusty. After removal of the circlip it took a lot of persuasion and penetrating oil to remove the sealing cap.
Inside you'll find two springs on either side of a shuttle valve. The FSM says you are NOT to dismantle this part any further. I didn't.
Next remove the bolts that hold the output shaft cap in place. This is the part from where the Pitman arm shaft / output shaft emerges.
Remove the little O ring on the back of this cap. Remove the large seal on the outer surface of the cap after removing the circlip.
Next remove the lock nut on the adjusting screw which is positioned at the other end of the shaft that holds the Pitman arm (see photo below). You will probably need to hold the screw thread still with a 6mm Allen key. Next screw this thread all the way into the steering box with the 6mm Allen key. The whole shaft will come out.
