How do I flush my brake fluid on a 2001 A6 quattro 2.8. I topped it off with bad fluid..

 

Why do you think it is bad?

 

By bad fluid, I assume you mean wrong DOT spec. Not sure on the specifics of if you fucked anything up, but just do it like a brake bleed and just keep running fluid through the system. Make sure you don't run the master cyl. dry too. Or you can pick up a power bleeder, hook it up to your air compressor and suck the fluid out. Brake bleeder is a little extreme for one time use, but its great when you bleed/flush brakes all day like I used to.

 

Replace/flush brake fluid every 3 years. Regardless of miles.