mattc12

Hello everyone, yesterday I worked on replacing the front and rear brake pads on my 06 A6 Quattro. Worked with a family friend who has had a long life in mechanics and we were able to get through the front pads pretty easily after learning the differences between most other cars brakes and the Audi's. When we got to the rear pads, however, we hadn't realized that I needed the VCDS to properly retract the Piston head to allow replacing of the pads. After figuring that out we tried to put the old pads back on because they weren't that bad anyways, just replacing them because might as well if doing the front. Anyways, we found a tutorial on how to wind back the E brake to push the piston back, but before that could happen I accidentally triggered the parking brake itself which popped the cylinder out of the Piston we were working on and that was a whole ordeal to fix but eventually we did after most of the brake fluid on that side of the car emptied itself from the open piston. Eventually we got that side put together again with the new pads and went on to the opposite side for obvious reasons. In Hind sight I now realize that we probably should have just put the old pads back but it's whatever. Last brake was relatively simple, got the old pads out and were able to replace everything. Since I had first activated the E Brake, the car was giving off warnings that the parking brake was ****ed up, which I attributed to the fact that we had been disconnecting them before working on them. After we put the tires back on we bled the lines according to what Audi has specified, starting back right and ending front left. Brakes felt great and ready to go. But I was still getting the parking brake warning lights so I turned it on and off again and the warnings went away. However, after I did that I lost all response in my brakes. We tried bleeding them again multiple times, and fluid was clearly coming out of the bleed valve on all four brakes. The rear brakes though had a small dribble compared to the front though, constant but very small pressure compared to the front which basically squirted fluid all over my arms. Any idea of what's wrong? We're thinking it's the rear calipers but any insight from you all would be very much appreciated. Thanks!

mattc12

Extra info:

-wheezing noise heard from around the brake fluid tank in the hood when pumping brakes

-brake pedal will begin to feel firm after 5ish small pumps but will fully depress to the floor if you hold your foot on the brake. Can barely hold car in reverse from moving itself without pushing the gas pedal.

-have not tried disconnecting battery if that could be something that might help.

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kelisko

It sounds like your brake master cylinder is ****ed up. While bleeding, did you check the brake fluid level and made sure it never went below the MIN mark? If air gets into the cylinder, that's the end of it.

mattc12

I did not no, I was never at the front of the car during the bleeding process. We're going to try replacing the rear calipers and if that doesn't work I'll look into the master cylinder.

kelisko

Do not waste time and money on the calipers. Your master cylinder is gone for sure. You will find here a proper way to bleed your brakes. Read it carefully. https://www.audiworld.com/forums/a6-...05-c6-2760602/

mattc12

Thanks Kelisko, yeah that's what I am thinking now as well. Didn't mind replacing the calipers cause the old ones were grimy as **** and I like new shiny things. And I found that guide online the other day while I was working on it, thanks again though!