Nine problems related to brake disc have been reported for the 1998 Audi A4. The most recently reported issues are listed below.
In wet conditions (rain or slush), brakes intermittently fail to respond for several seconds, then grab normally. Been this way since I took delivery of car. This is not normal wet weather braking force reduction. More like no brakes at all for a few seconds. I believe the brakes are getting wet internally due to lack of proper shields, but dry themselves off after a few seconds of application, which would explain the several second delay followed by normal braking. The dealer has inspected all braking system components twice for me and found nothing unusual. Lots of other Audi A4 owners complain about the same problem. No other car I have ever owned or driven has behaved like this in wet weather. Especially at highway speeds the braking delay is extremely dangerous, paticularly since it is intermittent. You just never know when the car will decide not to stop when you need it to! the only way I have found to deal with the problem is to apply the brakes every ten or fifteen seconds to k eep them dry. But that, too, is dangerous, since following traffic goes bananas seeing my brake lights come on all the time for no apparent reason. I have complained to Audi of America, which claims they know nothing about this problem and have not had other complaints about it. They are lying, because I know other A4 drivers who have also complained bitterly to Audi of America and their dealers about this problem. Please help us!.
During wet weather, the brakes takes several seconds to catch after the pedal is depressed. This has caused many near accidents since this behavior is not normal nor expected. Dry weather braking is just fine. I am very concerned about this problem and have contacted Audi of America and my dealer. They do not have a solution for the problem yet. I need help!!.
Brakes ineffective for 1-2 seconds during heavy rain.
There is a 2 sec. Delay for brake response when wet. Much worse than any other vehicle I have driven. This will cause accidents. Vehicle will not stop in published distance when brakes are wet. New brake pad material is required . There are already many other reports of this same problem in your data base.
In heavy rain or after washing car brakes do not work for about 1-2 seconds after application. It is very scary and dangerous imo.
Brakes do not "grab" in the wet/rain. There appears to be a one to two second delay between stepping on the brakes and the car slowing done. I have noticed this same delay, in dry weather, at highway speeds of 50-60 mph.
Brakes noisey and showing excessive wear.
During or after raining, initial braking has no response for about 1 - 2 seconds. Then the brakes slowly build up friction to engage stopping power. I realize that wet roads cause some brake performance loss, but this exceeds the norm. There are also many other A4 owner complaints about the same problem on the A4. Org forums.
Brake performance poor when wet. Unsafe in a panic stop.