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

A pump body for governing hydraulic actuators of disk brakes for bicycles or motorcycles, comprising:

• a cylinder with a chamber for compression of the fluid, communicating with the actuator;
• and
• a piston assembly, mobile with respect to the cylinder and provided with a stem and a primary gasket, wherein a movement of downstroke of the piston determines a reduction of the volume of the compression chamber and the displacement towards the actuator of a corresponding volume of working fluid, and wherein, in said movement of downstroke, the piston is mobile between a first position upstream, a second, intermediate, position downstream, and at least one third position downstream, wherein given the same extent of the movement of the piston the reduction in volume of the compression chamber is greater upstream of the second, intermediate position with respect to the volume displaced downstream of said second, intermediate position.