A vehicle antilock braking system having an operator controlled master cylinder for developing a first source of pressurized fluid and a second source of pressurized hydraulic fluid for selectively supplying rebuild pressure after an antilock event to simultaneously provide for actuation of each wheel braking device. A solenoid operated first flow control valve for each wheel controls communication of either the first source or second source of pressurized hydraulic fluid to the braking device and the braking device to a low pressure return. A hydraulically operated second control valve has a first inlet port connected to receive the first source of hydraulic pressurized fluid and a second inlet connected to receive the second source of hydraulic fluid and an outlet port connected to the first flow control valve. A bypass pressure regulator responsive to the first source of pressurized fluid and the second source of pressurized fluid supplies pressurized hydraulic fluid from the second source to each of the hydraulically operated second control valve when the operator controlled master cylinder supplies the first pressurized hydraulic fluid to the braking device. The pressure of the second source is directly proportional to the pressure of the first source and when sufficient to overcome a resilient member in the second control valve is supplied to the first valve to independently operate braking device.