BOLT 8T7008 - Caterpillar

Inspect the bearing of the turbocharger if any unusual sound or vibration is noticed.A quick check of the bearing condition can be made without disassembling the turbocharger. This can be done by removing the piping from the turbocharger and inspecting the following items.
The compressor impeller
The turbine wheel
The compressor coverRotate the compressor and the turbine wheel assembly by hand and observe by feeling excess end play. The rotating assembly should rotate freely. There should be no rubbing or binding of the rotating assembly. If there is any indication of internal damage to the rotating components of the turbocharger, replace the turbocharger.
Illustration 1 g00320945
Checking turbocharger rotating assembly end play (typical example)End play is checked with a dial indicator. Attach a dial indicator with the indicator point on the end of the shaft. Apply forward and backward force to the shaft of the turbocharger. Make a note of the total indicator reading.If the end play is more than the maximum end play, rebuild the turbocharger or replace the turbocharger. A measurement that is below the minimum specification could indicate that there is carbon on the turbine wheel. The turbocharger should be disassembled for cleaning and inspection.A more reliable check of the bearing conditions can be made only when the turbocharger is disassembled. The bearings, the shaft journal, and the housing bore diameters can actually be measured.Note: Do not cock the shaft. This could result in a false reading.