Method of manufacturing piston of pump for brake system and pump for brake system including the piston

A pump for brake system comprising:

• a piston disposed in a bore formed in a modulator block comprising a suction port and a discharge port, and having a hollow shape in which an inlet path communicating with the suction port is formed, wherein the piston is slidably disposed to be moved in a reciprocating manner within the bore;
• an inlet valve provided in the piston;
• a seat member provided in the piston, attached to the inlet valve, and having a communication hole opened or closed by the inlet valve;
• a valve seat provided in the bore, partially surrounded the piston at a predetermined distance from the piston to form the inlet path as a pressure chamber to press oil, and provided with an orifice;
• a piston spring disposed in the pressure chamber to press the piston;
• an outlet valve provided on the valve seat to open or close the orifice;
• and
• a cap coupled to the valve seat to support the outlet valve, fixed to the modulator block to open or close an open end of the bore, and forming, by coupling with the valve seat, a discharge chamber connected to the discharge port.