Abstract: A control valve for controlling the pressurisation of a power chamber of the booster comprises a spool working in a bore in a boost piston. The spool carries longitudinal spaced radial seals, a first one of the seals being disposed so as to prevent fluid from a radial high pressure supply port entering the power chamber through the spool at least when the booster is in an inoperative position. Movement of the spool in a forward operating direction, in response to an input force, causes the first one of the seals to uncover the port so that fluid can enter the power chamber through the spool. The other seal is adapted to uncover a radial return port connected to a reservoir when the input force is released.

Abstract: A liquid-immersed disc brake has a housing containing rotatable and stationary members operated by a wedge device for brake actuation from actuating means. The brake is supplied with cooling liquid, of which the flow is controlled by a valve, a portion of which is incorporated into the housing. The valve is closed by action thereon of the actuator means and opened so as to admit cooling liquid to the brake as a result of the actuator means performing an actuating movement.