[JimAB]

While bleeding brakes, the pump monkey said the pedal went straight to the floor without me opening bleeder valve. I opened up the bleeder valve while pedal was down and fluid, which had been spurting out, was now barely a trickle. I got in the car and pushed the pedal several times. Pedal goes straight to the floor with little resisitance. I can hear fluid swooshing around in the master cylinder. I don't see any leaks. Does this sound like problem with master cylinder, vaccum booster or both? Shouldn't the pedal get really stiff and not go down at all after pumping the brakes several times with the engine off if the vaccum booster is okay?

 

[284037]

http://www.benzworld.org/forums/w201-190e-d-class/1372325-brake-flush-step-step.html