Steering Knocking

a4 tdi 1998 avant.

If I rock my steering wheel gently back and forward I can feel a slight knock. During it's MOT it failed and I replaced a lower suspension arm due to a worn ball joint and a antiroll bar drop link, the car handled a lot better but I still have this slight knock. The car did not fail because of this. it's been like it for over a year and doesn't seem to get much worse, but I'm convinced its still not handling spot on!
Any tips
Thanks

Mike

Has the car been lowered? My steering knocked a little but mainly on full lock - im not an expert but have you got newer parts one side of the car and not the other? it could be that one side of your suspension is better than the other - i had this problem and although everything was ok i changed the parts and the knocking (and bouncing in the steering rack) went away