Patrick, according to the Haynes manual, the master cylinder is withdrawn from inside the car. Here are the instructions: Remove driver's side facia panel. Unbolt crash bar from in front of the clutch pedal. Unscrew the securing nuts and remove clutch pedal mounting bracket. Note that the upper nut is difficult to locate. Squeeze together the tabs on the pushrod retaining clip and separate the pedal from the pushrod. Release the clip and withdraw the master cylinder from the mounting bracket by twisting it anti-clockwise. Note that there are no spare parts provided by Audi. The master cylinder should be replaced completely. Hope this helps a bit.