Pump body for governing hydraulic actuators of disk brakes for bicycles and motorcycles

A pump body for governing hydraulic actuators (6) of disk brakes for bicycles or motorcycles, comprising a cylinder (1) with a chamber for compression of the fluid (5) communicating with the actuator (6), and a piston assembly (2), which is mobile with respect to the cylinder and is provided with a stem (3) and a primary gasket (4), wherein a movement of downstroke of the piston (2) brings about a reduction of the volume of the compression chamber (5) and displacement towards the actuator (6) of a corresponding volume of working fluid (1).