From the Austin Magazine

The "Seven" and "Big Seven" steering boxes are of the "hour-glass" worm and sector type, provision being made for the adjustment of end play at the worm, end play in the steering sector shaft, and also the mesh of the worm and sector.

To take up end play at the worm, remove the end cover by taking out screws (2). With a knife blade separate and remove one or more of the thin shims. Replace the end cover and test for end play, removing further shims if necessary.

End play at the steering cross-shaft can be taken up by removing the shaft and adding one or more shims, as required.

To adjust the mesh of the worm and sector, slightly loosen the three set­screws (1), the lock nut (4), and turn the screw (3) on the "Seven", the nut (4) on the "Big Seven", clockwise to take up play. Tighten the screws and lock nut and test for mesh. This adjustment should be carried out with the road wheels in the straight-ahead position. On this type of steering there is a minimum back-lash in the straight-ahead position, the back-lash increasing towards full lock.