It's part # 116 589 06 21 00.
I believe it is an 8 X1.0 bolt with the end sharpened. Can't be 100% sure of the dimensions; maybe 85% sure?
Length doesn't matter; maybe an inch and a half. It just stops the steering nut/working piston in a midway position by the sharp end sticking into a "dimple" inside.
See 46-412 in the manual. Good luck
Where (anatomically; not geographically) did that tick bite you?