One problem related to power assist brake has been reported for the 1997 Audi A4. The most recently reported issues are listed below.
My 1997 Audi A4 has experienced almost non braking in cold/wet conditions. When brakes are initially applied during these conditions there is almost zero braking for 50 feet at 35 mph or less. I have come very close to rear ending a few cars that cut in front of you. I have contacted Audi of America and there response was that no known poor braking condition exists when brakes are cold/wet. Yet there is a news bulletin on Audi's own european web site indicating that there is a problem with brakes when wet. . Read more...