The front hub attaches to the steering rack mechanism with a ball joint at each end. The 17 mm nut was easy enough to remove, but even with a ball joint separator, and some hammering on the relevant steel part, I have been unable to separate the ball joint, in six out of six cases.

One thing that I know to be a no-no is to hit the bottom of the ball joint, in the direction that removing it would go. Such hammering, I’m told, doesn’t just damage the thread, but it makes the ball joint expand within the housing and makes it harder yet to remove.