ARMY TM 92815-256-24
AIR FORCE TO 38G1-96-2
MARINE CORPS TM 2815-24/5
There will be some play because bearings inside center housing are free floating.
Next, check shaft end-play by moving shaft back and forth while rotating. There will be some end-play but
not to extent that wheels contact housings.
3-13.3.1 Radial Bearing Clearance Test.
This test will give an indication of condition of radial bearings within center housing and rotating
Fasten a plunger-type dial indicator to turbocharger mounting base. Assemble an extension adapter and a
2.0 inch (51 mm) indicator extension rod onto dial indicator.
Position indicator tip (through center housing oil return) on center of shaft. Preload indicator tip and zero dial
Grasp rotating shaft at both ends and move shaft toward indicator then away from indicator. Use care to move
shaft in same direction as dial indicator tip travels and apply equal pressure at both ends of shaft.
Observe and record total indicator reading. Bearing clearance specification is 0.003 to 0.006 inch (0.08 to 0.15
If total indicator reading is not within specification, replace turbocharger.
3-13.3.2 Axial End Play Bearing Test.
This test will give an indication of condition of thrust bearing within center housing and rotating
Mount base dial indicator so that indicator tip rests on end of shaft. Preload indicator tip and zero dial on
Move shaft axially back and forth by hand.
Observe and record total dial indicator reading. Bearing end play specification is 0.001 to 0.004 inch (0.025
to 0.10 mm).
If bearing end play is not within specification, replace turbocharger.
If turbocharger failed because of foreign material entering the air intake system, be sure to examine
the system and clean as required to prevent a repeat failure.
Inspect the rubber hose at the end of the turbo oil return line for damage or cracks. Replace as
necessary. Since the greatest amount of suction occurs between the air cleaner and turbocharger, it
is essential that the hose connections are tight to prevent entry of dirt into the engine.