T M 9 - 2 8 1 5 - 2 0 2 - 34 (3) (4) (5) (6) (7) (8) (9) (10) Install shims (44) and back plate (43) on  center  housing  assembly  (12). Using  fabricated  back  plate  torquing tool, torque back plate to 25-30 Ib-ft (34-41 N-m). Lubricate bearing (42) with engine oil. Install  bearing  in  turbine  side  of center  housing  assembly  (12).  Install snap ring (41 ) in center housing assembly. Turn  center  housing  assembly  (12)  so compressor  side  is  up.  Install  second bearing  (42). Lightly coat seal ring (47) with silicone  lubricant.  Install  ring  in  center housing  assembly  (12). CAUTION Do not scuff or score inner surface of bearings while pushing shaft through bearings. Turbocharger will not operate long with damaged bearing  surfaces. Lubricate  bearing  journals  of  rotor assembly (31 ) with engine oil. Lower center  housing  assembly  (12),  with back plate (43) down, over rotor assembly. Install thrust washer (39) on shaft of rotor assembly (31 ). Position holes and cutout in thrust washer over pins (48).  Seat  thrust  washer  flat  against center  housing  assembly  (12). Install piston ring (40) on thrust collar (38). Install thrust plate washer (37) and thrust collar (38) in thrust plate (36). 6-49