pdisme

Is it just me or is the master cylinder reservoir in a really stupid location and very hard to actually see the fluid level? I just did my first brake flush on my Q7 last night and found it very difficult to see where the fluid level was. I used a flash light, direct, indirect, and it still didn't make it any easier since the reservoir is wedged down in there. Are there any tricks to make this part easier? I'm still just guesstimating that I ended it up between the MIN and MAX markers.

Also, while doing the flush, I seemed to only use about 1/2 liter of new fluid total, which is half as much as the Audi service manual says to expect to remove from the system. It's been over three years since the last change (new car) so it was fairly obvious when the new fluid made it out of each caliper. I got a couple air bubbles out total, and the feel was much better afterward, so I feel like it was successful, but perhaps I should have bled more out regardless of the fact that it seemed to change from old to new? I did have someone helping on the brake pedal, rather than using a pressure bleeder (which the service manual also uses), so perhaps that's more efficient?

B490MTL

Did you bleed starting with the outside bleeder and then the inside?

pdisme

Yep went by service manual; drivers front, inside-outside, passenger front same, drivers rear inside/outside, passenger rear same. Service manual was specific though; should get 0.2L out of the fronts, each, and 0.3L out of the rears, each.

pdisme

Oh, just to confirm; the way I posted it is what I did, inside bleeder screw, then outside, as that's what the manual said: "If there are two bleeder screws on each brake caliper, first bleed the inner, then the outer bleeder screw."

B490MTL

Usually to bleed the brakes you start at the rear with the caliper the farthest from the master cylinder.

pdisme

That would contradict what the service manual says to do; Audi must have a reason for specifying the order they did.

J. Patterson

Tradition dictates rears first but that originated when cars had a single brake line from the master cylinder that branched off to each wheel. Today with ABS and individual lines for each wheel, that is not necessarily the best procedure. It WILL work though. I still do it out of habit. Also,On four or six piston calipers bleeding the outer first will also bleed the inner too except for any air bubbles trapped at the top. Just be sure to bleed enough total to get to new fluid. Whichever caliper you do first, bleed more there as you are clearing the old from the reservoir. I use a turkey blaster to remove as much of that as I can before I refill with new and hook up my pressure bleeder.

B490MTL

I just re-read the procedure I had taken for my 2007 and it is quite different from yours. Where did you take your technical info because you have a pre-bleeding to do, here's what I have.

pdisme

Here's the 2014 service manual steps (pdf)