While we're on the topic, any ideas what can cause the brake pedal to not firm up even after 6-8 rounds of bleeding? I just replaced my booster/master cyl and I def introduced air into the system since I had to take everything off incl the 2 brake pipes that go to from the cylinder (E53 4.8is).

I have bled over two litres of fluid out of the system (I also use ISTA-D to cycle the ABS/DSC pump) - no bubbles coming out at this point however the pedal is still stupidly soft. The bleed pattern I used is rear right, rear left; front right, front left;

Also, is the pedal doesn't feel uniform to press down - about 1/3 of the way its kinda difficult the the last 2/3 of the way its VERY easy!

Is my master cyl busted?