a cylindrical retaining wall 79 that receives of lip 75 of thrust washer 71 a skirt 81 depends from impeller 67 surrounds the inlet of impeller 67 and slidingly engages an outlet portion of diffuser 69 deformed portions 83 are formed in the rim of retaining wall 79 adjacent each flat 77 deformed portions 83 bear against each flat 77 to prevent rotation of thrust washer 71 flats 77 avoid having to deform any portion of the tungsten carbide washer 71 to create an interference fit the staking operation for deformed portions 83 may be as described in connection with the first embodiment the plan view of fig8 discloses shallow recesses 87 formed in the mating surface of impeller thrust washer 71 these recesses assist in lubrication and do not form a part of this invention similarly diffuser 69 has a retaining wall 85 that closely receives the lip of diffuser thrust washer 73 it has deformed portions also that engage flats on the outer diameter of diffuser thrust washer 73 the same procedure as described in connection with the first embodiment may be used for performing the staking operation referring to fig1 portions of two pump stages 89 are shown these stages being a third alternate embodiment impellers 91 93 are located within diffusers 95 96 respectively each diffuser 95 96 has an outer wall or shell 97 that is stationarily mounted within a housing not shown each diffuser has a central hub 99 that provides radial support for one of the impellers.