A centrifugal well pump assembly has a non-rotating diffuser between upper and lower rotating impellers. The upper impeller has a cylindrical skirt on a lower side that rotates within a diffuser receptacle. The lower impeller has a cylindrical balance ring on an upper side that rotates within a diffuser cavity. Impeller sleeves are bonded to the skirt and balance ring. Diffuser sleeves are bonded to the diffuser receptacle and cavity. The diffuser sleeves are of a harder material than the impeller sleeves. Each of the impeller sleeves has upper, intermediate and lower circumferential rows of inserts. Each insert has a face flush with the impeller sleeve and is in sliding engagement with one of the diffuser sleeves. The inserts in the intermediate row may be rotationally staggered relative to the inserts in the upper and lower rows to create serpentine flow paths for well fluid leakage.