Abstract: A pressure differentially controlled valve for use in a two stage servomotor to prevent reversion from the second stage to the first stage. A first valve initially moves to transfer the output of a servomotor from a first piston to a second piston. A pressure differential responsive second valve prevents the output of the second piston chamber from being communicated to the first piston chamber by moving thereafter with the first valve until an input force is terminated.

Abstract: A fluid pressure brake system for a bicycle or a motorcycle having a master cylinder which is provided with an excess portion extending from the end of the cylinder to have a given length more than a maximum pressure stroke of the piston of the master cylinder; this portion is provided internally thereof with an adjusting member controlling the inner volume thereof. Thus, the adjustment of the adjusting member keeps the brake action so as to be constantly responding to a predetermined swing of an operating lever at a handle bar despite leakage of fluid and wear of brake padding, thereby making it possible to perform consistent braking action.