E55 Brake Question

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

No... brake booster has no effect on retracting the piston. Brake booster makes it easy to stop the car via vacuum. Master cylinder is responsible for holding brake fluid and exerting pressure when braking along with ABS.

I would first check the master cylinder... with engine off... press the brake pedal ever so slightly to see if you feel 'free play' before you contact resistance... use your hand to feel this.

If you don't sense this free play then I would check your brake hoses... have car running... someone pressing pedal and you grab the brake hoses with a fist... one at a time... and feel the expansion of the hose... if one is worse than other... I'd change the hoses. This is what I am suspecting... one of your hose expands too much...