One problem related to power assist brake vacuum hoses, lines/piping, and fittings has been reported for the 2002 Audi S4. The most recently reported issues are listed below.
The brakes boost/vacuum assist line check valve cracks apart into two pieces. This causes the total loss of the power assisted brake system in the car and subsequently makes it very hard to stop the vehicle. There is no warning about the pending loss of brakes. One second you have brakes the next it feels like you are trying to push a brick thru the floor of the vehicle trying to get it to stop.
| Brake Disc problems | |
| Brake Disc Pads problems | |
| Power Assist Brake Vacuum Hoses, Lines/piping, And Fittings problems | |
| Brake Disc Rotor problems |