My 1999 E55 brake pedal has always required upwards of 2 inches of pedal
travel before braking power is felt. I had the brake booster replaced
and the brakes bled as well as new pads. Recently, I pulled the wheel to
inspect. I noticed that I could spin the front rotor without any pad
pressure whatsoever on the disk. Normally, in our cars, when spinning
the rotors, a certain amount of friction is sensed by basis of a slight
pad pressure being exerted. This is because, after a normal braking
operation, the caliper pistons move back only so slightly, but
essentially keep the pad up tight against the rotor. My E55 seems to
retract the piston after a braking operation. Thus, when I press the
pedal, it has to make up that distance, first, before brake activation.
 What could be the remedy for this? Is it possible that the booster is
reversing fluid pressure after a braking operation and causing the
pistons to retract slightly? I'm baffled. Thanks for your help
JB
88 300E
99 E55