Check Valve

Check valve controls brake fluid flow into piston chamber. System brake pressure is limited to pressure generated by master cylinder when ABS is activated. If brake pressure at wheels becomes greater than master cylinder pressure, check valve unseats and brake fluid returns to master cylinder until pressure is equalized. If ABS was activated during low brake pressure, such as on ice, pressure control piston on front brakes will be driven to top of chamber. Check valve will be unseated and system returned to base braking pressure until wheel lockup occurs again.