[jim sewell]

Hi Tony
As Phil mentioned a heavier lubricant should stop the leak which is usually past the threads of the bolts and the worm adjustment nut.

Suggest you clean it down thoroughly, remove one bolt at a time and allow the box to drain and then seal the threads with some gasket sealer or tape.
The traditional type greases were frowned upon for use in steering boxes because as they became less fluid over time the steering mechanism cut a path through the hard grease and moving parts were starved of lubricant.

Refill the steering box with a grease containing molidium ( 5% ) which is a very sticky grease and will not move away from the moving parts.

This will be an easier fix than dismantling and having to reset the steering box bearing preloads.
Regards
Jim S.