WARNING: This page is about a different car, the 2005 Audi A4, 2004 Audi A4, 2003 Audi A4, and 2002 Audi A4. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Identifying Installed Position Of Breather
Courtesy of VOLKSWAGEN UNITED STATES, INC.
The breather must project 21 mm out of housing, after being pressed in.