audis4fun

I believe it was around 30k miles that I started to notice that the brakes on my '00 S4 didn't feel right. When I press the pedal they come on slow (long pedal travel) and then apply very agressively, hard to modulate. Further, if I pump the pedal once the travel decreases and the application is more progressive and easier to modulate. The rear brakes had new pad at 24k when I bought the car (used "Assured"). I spoke with the dealer about this (while still under factory warranty), thinking to myself that perhaps there was air in the lines. At my request they flushed and bled the system, not once but twice, and said nothing could be done. I went to another dealer just before the 3 yr factory warranty was up and they replaced the rear rotors/pads and bled/filled the system, but I still noticed the symptoms. Finally at 36k I went back to the 2nd dealer and they spoke w/ Audi and the solution was to replace the front pads and rotors -- this time at my expense, they were kind enough to split the cost with me. The symptom was gone for a few months and miles, but... Now at 39k I am experiencing the same symptoms. What could the problem be? More importantly, how can I get the dealer to diagnose and fix it -- I'm still covered by the Assured warranty.

George @ BostonAudi

Its entirely likely you've got a problem, but the S4 brakes aren't terribly linear from the factory. Some bite more quickly than others, but they've all seemed "wrong" to me.

Its possible there's a problem with the master cylinder, or ABS pump, as well.

Once the pedal has firmed up, does it stay firm if you don't release the pressure? If it engages firmly low, and then after pumping engages firmly higher, but doesn't sink under pressure, thats consistent with what I've seen a number of S4's do. Seems wrong to me, too, but "normal".

I'd compare yours to another car...

audis4fun

Thanks. Yes it appears to stay firm. The part that has me puzzled is that the problem is progressive, appearantly tied to brake wear (?). Replacing rotors/pads was such an improvement!

I haven't driven other cars so I'll have to try that. Although in speaking with the 2nd dealer's service rep he noted a symptom and indicated that it is not a typical behavior he's seen.