Abstract: A vehicle brake system includes a source of fluid pressure adapted to supply a braking force to at least one brake actuator and a modular valve unit fluidly coupling the brake actuator to the source of fluid pressure. The modular valve unit includes a plurality of valve modules. Each of the plurality of valve modules includes a housing in which working elements of the valve module are contained and at least one port in the housing adapted to be an input port or an output port, the at least one port being adapted to cooperate with and be directly fluidly connected to at least one port of another of the plurality of valve modules, thereby obviating the need for tubing or piping. Each of the plurality of valve modules is self-contained and defines a stand-alone unit capable of operating independently of any other of the plurality of valve modules.

Abstract: A vehicle brake system includes a source of fluid pressure adapted to supply a braking force a brake actuator including a parking brake chamber, and a combination valve fluidly coupling the brake actuator to the source of pressure, the combination valve having an inlet fluidly coupled to the source of pressure and an outlet fluidly coupled to the brake actuator. The combination valve includes within a single housing (i) a solenoid responsive to electrical signals to move from one position in which the parking brake chamber is fluidly coupled to the source of pressure in order to pressurize the parking brake chamber and release the parking brake, and another position in which the parking brake chamber of the brake actuator is vented in order to exhaust pressure within the parking brake chamber so that the parking brake is applied, and (ii) at least one of a manifold, an inversion valve, a double check valve and an anti-compounding valve.