a controlled motor vehicle brake system including a first and a second piston which is displaceable in a housing and has a captive spring a first end of the spring bearing at least indirectly against the piston and a second end thereof against a sleeve which is displaceable with respect to the piston and the movement of which with respect to the piston is limited by a pin provided on the piston and by a stop washer the stop washer being arranged on a free end of the pin in order to avoid impact noise upon rapid release of the brake the stop washer of the first piston has a device for the damped abutment of the sleeve application_number US 201013384429 A description fig1 shows in longitudinal section a known master cylinder 1 which is used for example in a controlled brake system with anti slip control asr and or electronic stability program esp and has a plunger type tandem configuration the master cylinder 1 comprises a first and a second piston 3 4 which are displaceable in a housing 2 a circular sealing element 5 6 with a dynamically loaded inner sealing lip 26 27 and a statically loaded outer sealing lip 28 29 being provided in an annular groove 23 24 of the housing 2 the dynamically loaded inner sealing lip 26 27 bears with a first sealing face against the piston 3 4 and the statically loaded outer sealing lip 28 29 bears with a second sealing face against a base of the annular groove 23 24 an outer face 30 31 of the pistons 3 4 serves as a guide surface in an unactuated state of the master cylinder 1 shown in fig1 a first and a.