The vacuum pump (2) has a suction valve (3). It has a connection part (5) inserted in the mounting orifice (4) of the pump with an O-ring (6) and secured to prevent axial movement by a clip member (7), which is formed by two clip arms (9) projecting beyond the connection part and spreading over and latching on to steps (10) on the vacuum pump. Preferably, a groove containing the O-ring within the opening of the connection (1) forms a valve seat (13) for the suction valve. The closing body (14) of the valve is loaded by a spring (15) which is supported by a spring star (16).
