M11 Series – Service Manual – 001-052   Vibration Damper, Viscous

Remove the fan drive belt. Refer to Procedure 008-002.

Remove the clamping plate, crankshaft pulley, and vibration damper. Refer to Procedure 001-022.

WARNING  When using solvents, acids, or alkaline materials for cleaning, follow the manufacturer’s recommendations for use. Wear goggles and protective clothing to reduce the possibility of personal injury.

Clean the damper with a solvent cleaner.

CAUTION  The silicone fluid in the vibration damper will become solid after extended service, which makes the vibration damper inoperative. An inoperative vibration damper can cause major engine or driveline failures.

Check the vibration damper for evidence of fluid loss, dents, and wobble. Inspect the vibration damper thickness for any deformation or raising of the damper front cover plate.

If any variations or deformations are detected, refer to the Shop Manual, M11 Series Engines, Bulletin 3666075, or contact a Cummins Authorized Repair Location for service.

Check the mounting web for cracks.

Check the housing for dents or raised surfaces.

Replace the damper if any of these defects are identified.

Examine the damper and record the vendor identification, date code, and part number.

Using the date code, determine the type of bearing material in the damper.

Date codes followed by a “P” represent dampers with P.T.F.E. (Teflon) bearing material.

Date codes not followed by a “P” represent dampers with nylon bearing material.

Fabricated vibration dampers are the most common type and can be identified by a weld bead on the front center section of the damper where the housing joins the mounting flange.

Remove the paint from four locations on either side of the damper.

Measure and record the vibration damper thickness at two points at each of the four locations.

• Measure the thickness at 3.18 mm [0.125 in] from the outer lip.
• Measure the thickness at 25.4 mm [1.0 in] from the outer lip.

This procedure will result in a total of eight measurements.

If the variations between any of the eight measurements exceed 0.25 mm [0.010 in], or if the thickness at any point exceeds 45 mm [1.772 in], replace the vibration damper.

WARNING  Use insulated gloves, Part Number 3823730, when handling heated parts. Hot parts can cause serious personal injury.

To check for oil leaks, spray the damper with crack detection developer, Part Number 3375434.

Heat the damper in an oven, rolled-lip side down, for a minimum of 30 minutes, but not longer than 2 hours.

Replace the damper if oil leaks are found.

Install the vibration damper, crankshaft pulley, and clamping plate. Refer to Procedure 001-022.

Install the fan drive belt. Refer to Procedure 008-002.

Clean the outside surface of the vibration damper.

To measure damper eccentricity (out of round), install the dial indicator gauge, Part Number 3376050, and extension Part Number ST-537-4, on the gear cover as indicated.

Rotate the crankshaft with the accessory driveshaft one complete revolution (360 degrees), and record the total indicator movement.

Replace the vibration damper if the eccentricity exceeds 0.28 mm [0.011 in].

To measure wobble (face alignment), install the dial indicator as shown.

Push the crankshaft to the front or rear of the engine and “0” (zero) the indicator.

Rotate the crankshaft with the accessory driveshaft one complete revolution (360 degrees) while maintaining the position of the crankshaft either toward the front or the rear of the engine.

Record the total indicator movement.

Replace the damper if wobble exceeds 0.28 mm [0.011 in].