Found in Audi world.
There is a 18 mm bolt that sticks out of the bottom of the steering rack near where the steering shaft connects to the rack.
This 18mm bolt is the rack Pre load adjustment and it can be turned in small increments to tighten up the steering response. If you have two people available, one person can turn the steering wheel back and forth from inside the car, while the helper tightens up this Pre load adjustment in small increments until no more rattling or popping sounds are heard. Turn the bolt clockwise 1/16 to 1/8 of a turn at a time until the noise goes away and then turn it an additional 1/8 turn.
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http://forums.audiworld.com/showthread.php?t=1759068