A rotary vane suction pump that includes a housing that defines a pump chamber. A shaft is rotatably mounted to the housing. A rotor is fixed to the front end of the shaft to rotate in unison with the vanes. The vanes that form the fluid cavities, into which the fluid is drawn into and discharged from, are seated in radially directed slots that extend longitudinally, end-to-end along the length of the rotor. Discs located at the opposed inboard and outboard ends of the rotor are mounted to the shaft and rotor to turn in unison with the rotor. The discs have diameters greater than that of the rotor and the pump chamber. The discs thus close the ends of the pump chamber and the ends of the slots in which the vanes are seated.