Rubber Vibration Assembly
(1) Crankshaft. (2) Hub. (3) Rubber (4) Ring. (5) Alignment marks. If the damper is damaged, or if the bolt holes in the damper are loose fitting, replace the damper. Replacement of the damper is also needed at the time of a crankshaft failure due to torsional forces.
The vibration damper has alignment marks on the hub and the ring. These marks give an indication of the condition of the vibration damper. If the marks are not in alignment, the rubber part (between the ring and the hub) of the vibration damper has had a separation from the ring and/or hub. If the marks are not in alignment, install a new vibration damper.
A used vibration damper can have a visual wobble (movement to the front and then to the rear when in rotation) on the outer ring and still not need replacement, because some wobble of the outer ring is normal. To see if the amount of wobble is acceptable, or replacement is necessary, check the damper with the procedure that follows:
1. Install a dial indicator, contact point and other parts necessary to hold the dial indicator stationary. The contact point must be perpendicular (at a 90 degree angle) to the face of the outer ring of the damper, and must make contact approximately at the center of the outer ring.
2. Push on the front end of the crankshaft so the end play (free movement on the centerline) is removed. Keep the crankshaft pushed back until the measurements are finished.
3. Adjust the dial indicator to zero.
4. Turn the crankshaft 360 degrees and watch the dial indicator. A total indicator reading of 0.00 to 2.03 mm (.000 to .080 in) is acceptable.