Play In Steering Wheel On Hard Lock (video added)
 

Recently i noticed an occasional minor flaw when driving round a corner or roundabout but i could not quite put my finger on it. Now it seems to have gotten worse. There is substantial play in the steering wheel when its on hard lock, there is none when the steering is straight, there is none when its turned to the opposite hard lock. There is no knocks or anything obvious but sometimes it feels a bit harsh when going over a bump. WHat do you guys think the problem is?

Guys i made a video of what play im getting, on hard lock there seems to be some more slack that there is when its aiming straight, when straight is feels quite normal.

Engage lift mode and get a helper to gently do that while you look at the steering and upper suspension joints above/behind the top of the tyre.
What can you see moving without the roadwheel moving? If you can't see anything moving it will be the steering rack, if you can see something moving find where the play is.

Armchair troubleshooting points to a broken cup in one of your tie rod ends.

Hi thanks for your reply, i did as you suggested and i did not find anything obvious. With the engine off there is a loud knock but it sounds like its further in from the strut area although i cant be sure.

What the best way to check if iy is the steering rack and can it be adjusted?

Hi thanks for your reply. I did not feel anything obvious on the outer tie rod ends, do the inner tie rod ends have a ball joint?

Yes, the inner tie rod has a ball type joint.

Yes, rack can be adjusted, but extremely tedious and barely documented. From my own experience, if there is play in rack it is present whether straight or turned. With front wheels off ground, ignition on but engine not running. move steering wheel quickly back and forth a tiny fraction of a turn from center--like 10 degrees. If you hear clicking and maybe a little slack before road wheels turn, rack adjustment is suspect. The clicking is more reliable as a diagnostic from my experience; the slack feel is very subtle.

Look at your front tires. If worn on inside, reason to suspect suspension wear (and alignment) in general. #1 most common = upper control arms #2 = front sway bar links Lower arms are not common until odometer/miles are quite high, and tie rods are typically higher mileage as well. If first two haven't been done in last 75-100K miles, major suspects. They are essentially wear parts needing periodic replacement on a D3.

Tunes in video made any sound based diagnostics a non-starter.

Hi many thanks for your reply it was very informative. I will do another test the was you have suggested. I will make a video too without the engine on or the music, sorry about that. Is there a jacking point where i can lift both front wheels off the ground at once. I have a heavy duty trolley jack and the standard audi jack . thanks again.

No single jack point unfortunately, at least AFAIK. Would involve the engine subframe, which is dubious as a preferred method, and you would have to take the belly pan off. What I do is jack up each side and then fit a jack stand underneath. Even that is not super intuitive. Using the factory jack point then gives you a better option for the jack stand, but then you should have the puck sort of adapter that fits in there well and can be placed on top of a flat floor jack head. Sold online if you search, though not remembering right now exactly where I got mine. I have a few--some Audis and VW's use a seam type cut one to lock in, others have a raised semicircular bump several inches/maybe 100mm long.

Many thanks for your informative reply. I will just have to jack it up on each side and use my jack stands as i dont have a puck adapter at the moment. I will make and other video without music and engine off and i will also check the tyre wear. Ill get back to you soon.

This is a bit hard to put into words but I will give it a try. As the steering angle increases towards full lock in either direction the angle between the tie rod and the steering arm on the hub becomes less acute. (closer to a 180° angle rather than a 90° angle.) This being on the inner side since the rack in our cars is behind the axle. This changes the effect of slack in the joint of either the inner tire rod end or the outer tie rod end. Any slack that occurs in either place will be amplified or at least more easily noticed because of the extreme steering angle. As stated earlier the easiest way to check it is with both wheels off the ground and rocking the wheel back-and-forth while watching for slack at the tire rod . It will be more difficult to see it at the inner end due to the accordion boot that covers that joint. Keep in mind that this slack can also be caused by worn control arm ends. Anything that allows the hub to move. Good luck!