Is the ABS system working properly?
 

So did a brake fluid flush on the Q7 yesterday. Did the flush using a vacuum to pull the new fluid, Pentosin SUper DOT 4, thru. Anyways so after I got done with the flush took the car out for a little drive. While out I decided to test the ABS. Straight flat road, did an emergency style stop, brakes grabs as normal but as I pushed down harder the pedal dived towards the floor and I believe I felt the ABS engage. My concern is that I have never had a car that the pedal dived when the ABS engaged. I am used to feeling the pulsing in the pedal when the ABS kicked in. Is the pedal drop normal for Audis?

yep.. you wont feel it pulse in the pedal, just hear it and feel it in the chassis..

I frequently trigger ABS on steep descents on dirt trails w/traction control off.. this enables downhill descent mode and the ABS will fire off almost constantly, nothing in the pedal.. I just ignore the ruckus and keep on going and it does its job of keeping me pointed in the direction I'm aiming it.

Its dependent on ABS for much of its traction control, electronic lockers, etc.. if the driver got their foot rattled each time those engaged it'd probably be annoying at best, or distracting safety issue worse.

Thanks for the response Dread. So when your ABS kicks in, the pedal goes down farther (by a significant amount) in a quick motion? Not the same downward motion/rate as the normal breaking before the ABS kicks in.

yeah it feels like there's a check valve or something that takes the load off the pedal when its in over-ride.. thats probably why none of the hydraulic action makes its way back to the pedal.. i think its more pronounced in an emergency stop with all the abs active at once than a traction control situation where its just one or two of em firing off.. but usually I'm not paying too much attention to pedal feel when things gone pear shaped and im braking hard.

Ive overheated brakes towing down some steep ass grades (teton pass), those got spongy feeling real bad until they cooled down, but it was not really comparable in pedal feel to the pressure relief during abs activation.