Well a year has passed since I last updated this thread, so I thought I would at least record my latest winter project. I have just sent off an article about rebuilding my steering box to the magazine editor, which may be in the April edition. I wasn't planning to repeat it all here, but if anyone is interested in particular details, I'm happy to share what I've learnt. Like most jobs I suppose, it is actually fairly straightforward as long as you have the right tools. In particular, a puller to get the pitman arm off and a very low range torque wrench (3Nm full scale) to make the necessary adjustments. Here's what the innards of my box looked like when taken out of the box.
