Hydraulic braking system with slip control

A hydraulic braking system with slip control, for automotive vehicles, comprising:

• at least one working piston guided in a brake pressure generator, a booster piston of a hydraulic brake force booster for actuating the working piston,
• at least one wheel brake connected to the brake pressure generator and an electrically actuable auxiliary pressure source connected to the booster piston,
• a control and regulator electronic assembly for detecting the wheel rotating pattern of a wheel attached to said at least one brake and for controlling the wheel brake pressure by means of pressure modulating valves,
• an electronic sensor means for detecting the relative movement between a pressure rod attached to the brake pressure generator and the booster piston, the output signals of which are input to the control and regulator electronic assembly, wherein the electrically actuable auxiliary pressure source is formed of a floating piston and a servo drive, wherein the auxiliary pressure source is provided with a locking means for maintaining a holding force, wherein the locking means includes a fluid-filled, blockable pressure chamber the internal pressure of which generates the required holding force, wherein the locking means establishes a first hydraulic connection between the pressure chamber and an intake reservoir in which said first connection is inserted a check valve opening toward the pressure chamber and a second hydraulic connection established between the pressure chamber and the intake reservoir by means of an electrically actuable shut-off valve.