Two problems related to brake disc pads have been reported for the 1997 Audi A4. The most recently reported issues are listed below.
The brakes don't grab when driving in rain, snow, sleet etc. There's a "lag" of a second or two before the car begins to stop. This happens every time you attempt to stop the car in these conditions regardless of speed. There are no brake backing plates on the front rotors from the factory. The rotors are obviously getting glazed with water and the pads are ineffective until the rotors are cleared of water. Makes for a very dangerous driving condition in inclement weather!.
Lack of stopping when brakes are wet. At 1000 mi replaced all pads with german spec oem pads. Wet braking problems neglable. Did not need to wash underware as often.