Hydraulic braking system for an automotive vehicle

A hydraulic braking system for an automotive vehicle having a power source for generating a hydraulic power pressure, a reservoir, a master cylinder, a regulator and a plurality of wheel brake cylinders for braking respective road wheels, which are divided into a first group of wheel brake cylinders communicated with the master cylinder and a second group of wheel brake cylinders communicated with the regulator. The regulator has a housing defining therein a regulator chamber for introducing the hydraulic power pressure thereinto from the power source and regulating the hydraulic power pressure into a regulated hydraulic pressure in response to the hydraulic braking pressure generated in the master cylinder, and which is positioned in substantially coaxial relationship with the master cylinder and responsive mechanically to depression of a brake pedal. Accordingly, the regulator normally generates the regulated hydraulic pressure in response to the hydraulic braking pressure generated in the master cylinder, whereas it generates a hydraulic pressure in response to depression of the brake pedal when the hydraulic braking pressure is less than a predetermined value.