Abstract: The invention relates to a piston, through which a fluid can flow, for a piston pump, which piston has a longitudinal bore into which a spring-loaded inlet valve body is inserted. In order to be able to bring a helical compression spring, which loads the inlet valve body, to bear against an annular shoulder in the longitudinal bore and to be able to check and if necessary improve its seating after installation, the invention proposes to produce the inlet valve body in two parts comprising the inlet valve disk and the inlet valve stem and to join these two parts to one another after the helical compression spring has been correctly inserted into the piston. The inlet valve disk can for example be joined to the inlet valve stem by ultrasonic welding, thermoplastic riveting or screwing.