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To determine if repair of the vibration damper is possible or replacement is necessary, perform the following procedure. See Figure 31647 . ‪

Repair or Replacement of Crankshaft Vibration Damper Flowchart

To determine if repair of the pulley is possible or replacement is necessary, perform the following procedure. See Figure 21774 . ‪

Repair or Replacement of Crankshaft Vibration Damper Pulley Flowchart

Removal of Vibration Damper

Remove the vibration damper assembly as follows: ‪

  1. Prior to pulley damper removal, inspect the damper for wobble as follows:
    1. Remove paint from the face of the damper at four (4) points 90 degrees apart.
    2. Clamp/attach a dial indicator to the front cover. Position the indicator point on an unpainted surface and "zero" the indicator.
    3. Pry the crankshaft pulley forward and read the indicator.
    4. Record readings and repeat at each unpainted surface. If wobble exceeds specification, replace the damper.
    5. Note: Do not pry the crankshaft pulley back and forth. Pry only in one direction, to eliminate the possibility of replacing a damper for excessive wobble when the crankshaft end play was really excessive from any readings taken.

  2. Remove the pulley damper assembly as follows:
    1. Remove three (3) bolts and retainer.
    2. Install a universal puller using bolts long enough to hold the puller in place. Turn the forcing screw and remove the pulley damper assembly. See Figure 32281 .
    3. Vibration Damper Removal

    4. Remove bolts securing the front engine mounting bracket. Remove bracket. See Figure 32021 .
    5. Front Engine Mounting Bracket Removal

Inspection for Vibration Damper Streaking

A condition known as streaking may be observed on the vibration damper; see Figure 31541 . Detroit Diesel has established guidelines for replacement of the vibration damper when this condition occurs. ‪

Vibration Damper Showing Rubber Streaking

Rubber streaking may become evident as the rubber, found between the inertia ring and the damper pulley, begins its normal life cycle. see Figure 31542 . This process is caused by high temperatures generated within the damper as it absorbs the energy of the rotating crankshaft. The time required to generate this condition varies greatly due to differences in engine ratings and vehicle applications. ‪

1. Vibration Damper Pulley (Inner Member) ‪

3. Inertia Ring (Outer Member) ‪

2. Rubber Compound ‪

Vibration Damper Cross-Sectional View

Streaking generally occurs on both front and rear surfaces of the vibration damper. A damper showing signs of streaking does not require replacement and can remain in operation for some time. To determine when the vibration damper should be replaced, use the following guidelines: ‪

  1. Replace the damper when the rubber compound has recessed more than 10 mm (3/8 in.) depth across a 51 mm (2 in.) radius on both sides of the damper, see Figure 31543 .

    Vibration Damper Requiring Replacement

  2. Replace the damper if rubber member "chunking" occurs. Chunking is defined as the occurrence of deep splits within the rubber member, resulting in the loosening or breaking off of "chunks" of rubber.

Installation of Vibration Damper

Install the vibration damper assembly as follows: ‪

  1. Place damper directly on a hot plate. Mark damper with a thermomelt crayon, 388F (198C), and heat. When the crayon melts, use welding gloves and install damper on crankshaft nose. Be sure that keyway on damper aligns with key on crankshaft. Do not install damper when cold (room temperature).
  2. Install the damper retainer using the correct bolts.
  3. Prevent the crankshaft from turning and torque the bolts to specifications. Refer to Specifications in Section 1.A.