Abstract: An anti-lock hydraulic brake system with a hydraulic brake power booster (3) and two static brake circuits (I, II) is provided. Connected to one brake circuit (I) are the two rear wheels (HR, HL), while to the other the two front wheels (VR, VL) are connected by way of multi-directional control valve (11 to 16) which sever for the braking pressure modulation and/or the slip control. In the event of slip control, controlled dynamic pressure out of an auxiliary-pressure supply system (4, 5) is introduced by way of the brake power booster (3) into the static brake circuits (I, II) through the intermediary of two hydraulically isolated circuits with main valves (31, 32) which are independent of each other. A positioning device (42) for limiting the pedal travel communicates hydraulically with the main valve (31) of the rear wheel brake circuit (I). The main valve (31) controlling the dynamic fluid flow into the rear wheel brake circuit is equipped with an additional pressure monitoring switch (35).