A braking system includes a brake actuator which is moveable by pressurised hydraulic fluid fed to the actuator along a transmission line, in a first direction, to move a brake applying member to apply a braking force to a member to be braked, a master valve including an operating piston which upon operation of a brake operating member, moves in an operating cylinder, to direct the hydraulic fluid under pressure to the transmission line to apply the brake, the system further including a charging valve, the charging valve being operable when activated, to deliver a predetermined volume of pressurised hydraulic fluid to the master valve to move the brake applying member in the first direction towards the member to be braked to reduce the clearance between them, and the operating piston, when the charging valve is deactivated, being moveable in the operating cylinder to allow hydraulic fluid to pass from the transmission line thus to permit the brake actuator to move in a second direction opposite to the first direction to increase the running clearance between the brake applying member and the member to be braked.