(EN) An improved mechanical seal (40) for a pump includes a seal cartridge (42) slidably received inside an end plate (14). The cartridge (42) includes an outer cylindrical stator member (46) which is slidably received in the end plate (14) and an inner cylindrical rotor (44) which is rotatable within the stator member (46). The stator member is prevented from rotation in the end plate. The stator member includes a shoulder (98) which extends outwardly over the end plate and is captured between the end plate and the housing of the pump. A clinching collar (5) is fixed to the rotor member (44) and retains the rotor member of the cartridge to the pump shaft (70). The clinching collar (5) may pass through the end plate while attached to the rotor member and pump shaft (70). Lubricating passageways (41) in the end plate (14) allow lubricants to circulate past the seal cartridge bearing surfaces.