In a hermetically sealed motor pump unit for pumping a fluid, in combination, a rotor comprising an impeller and an elongated shaft, a sealed housing enclosing said rotor and having a fluid-tight well encasing an end portion of said shaft, a thrust bearing near the open end of said well for supporting the axial thrust of said shaft, said thrust bearing comprising a thrust plate mounted in said housing and a thrust collar mounted on said shaft, said thrust plate having a central opening the peripheral portion of which is hermetically sealed to said housing at the open end of said well, a pair of journal bearings located within said well at spaced points along said shaft for supporting the radial load of said shaft, means formed in said housing for supplying a lubricant to said thrust bearing, and electric motor means operable to apply a driving torque to said shaft at a point between said journal bearings, said motor means comprising an armature mounted on said shaft and an electrical field element mounted in said housing, said armature and said field element cooperating to rotate said shaft, and said impeller and casing cooperating to pump said fluid and said thrust bearing having a lubricant-conducting path connecting said lubricant-supplying means with the space between the confronting thrust bearing surfaces intermediate the peripheries thereof, the surfaces of said thrust plate and collar being constructed and arranged to inhibit radial flow of lubricant and, on rotation of said thrust collar, to draw lubricant through said path between the confronting thrust bearing surfaces and to increase the pressure between the confronting bearing surfaces and in said well and thereby exert an axial supporting force on said end portion of said shaft and supply lubricant under pressure to said journal bearings.