Pressing master cylinder operating rod into retaining clip - A - (in direction of - arrow -).

WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2008 Audi S4, 2008 Audi RS 4, 2007 Audi S4, 2007 Audi RS 4, and 2006 Audi S4. However, it is still accessible from the selected car via links, so may be relevant.