lower ball joint on wheel knuckle
 

Has anyone replaced this ball joint? If so, what new part did you use?
Thanks in advance.

This lower front ball joint on the suspension upright is a pressed-in fitting and is exceptionally difficult to replace without the correct tooling. Many shops will not replace these due to the difficulty. In fact the design was later changed to move the ball joint onto the wishbone, and it then becomes a lot simpler and easier.

No doubt somebody will now say its easy !

So, do you replace the whole assembly? Is this what they call the knuckle? Does the knuckle include this joint?

Unfortunately, yes, you have to replace the whole knuckle, (UK=Hub carrier), which comes complete with new ball joint. I was at a seminar in 2011 on the X350 and the head of an independent mentioned the great difficulty in replacing this very joint. Of course it was later redesigned to put the ball joint onto the wishbone, which makes replacement a lot easier.