[Vetracr]

If you push pedal down several times with engine off pedal should become harder as vacuum boost is lost. If it does not get harder you still have air in lines.

I had similar problem when installing 330 front brakes and rotors on my Z4. Look at front brake lines. The lines go up and over suspension. at the top of the loop air can get trapped. When I pressure bled the brakes I had to keep tapping the brake line at the top of the loop to free trapped bubbles. It took awhile but it worked. BMW design problem.

Another thought. Have you checked the slide pins on your calipers to see if they are properly lubricated or are worn. A stuck pin could cause a caliper to lock up causing the ABS to actuate.