Vehicle braking system having devices for controlling fluid flows between the pressurizing and assisting chambers of a master cylinder , a pressure source and a reservoir

A vehicle braking system including a master cylinder (64, 360, 510) having a pressurizing piston (80) fluid-tightly and slidably received in a cylinder housing (70) and cooperating with the cylinder housing to define a pressurizing chamber (88) and an assisting chamber (90) on opposite sides of the piston, a brake operating member (60) for applying a pressurizing force to the piston, a wheel brake cylinder (132) connected to the master cylinder for activating a brake (128, 130, 148, 159) for braking a wheel (6, 8, 10, 12), a hydraulic pressure source (188) for pressuring a working fluid, a reservoir (120), a first flow control device (194) for controlling flows of the fluid between the assisting chamber, and the hydraulic pressure source and reservoir, and a second flow control device (256) for controlling flows of the fluid between the pressurizing chamber, and the hydraulic pressure source and reservoir.