SERVICE MANUAL TIMING, GEAR TRAIN & FRONT COVER Section 7 Inspect the Vibration Damper as follows: Vibration Damper with Rubber Insert - 1. Visually inspect for abrasion, cracking or tearing of rubber at the inner or outer diameter of the rubber member. a. Replace the damper if the cavity depth is 3 mm  (0.12 in.) or more through 360. b. Replace the damper if voids 6.35 mm (0.25 in.) deep through 900 are found. 2. Inspect  alignment of Inertia Member (outer Iron Ring) with Hub: a. Locate alignment marks (made with a punch or chisel) on MOST "RUBBER" dampers. b. Measure   the   movement   between   the   hub and the inertia member. c. The marks normally fall on a radial line from the center of the damper hub.  If more than 1.5   mm   (0.06   in.)   misalignment   is   found, replace the damper. 3. Measure  wobble  on  the  front  face  of  the  inertia member as described earlier in this section. Inspect Vibration Damper The viscous type vibration damper consists of an inertia mass   (flywheel)   enclosed   in   a   fluid-tight   housing   but separated   therefrom   by   a   thin   wall   of   viscous   fluid (silicone    oil).        Any    movement    of    the    inertia    mass, therefore,  is  resisted  by  the  friction  of  the  fluid;  which tends  to  dampen  excessive  torsional  vibrations  in   the crankshaft. Damper   failure   can   lead   to   a   broken   crankshaft   and extensive  engine  damage.    Certain  guidelines  can  be followed    which    will    diminish    the    chance    of    damper failure: Figure 18. 1. Check the viscous damper visually for:   a. DENTS-Even   small   dents   can   cause   the inertia    mass    (flywheel)    which    floats    in silicone  fluid  to  contact  the  outer  housing. Such contact can cause damper malfunction.  Replace dented dampers. b. LEAKS-Clean damper thoroughly and inspect for silicone fluid  leaks.    Such  leaks can    possibly    occur    at    cracks    or    seam openings  in  housing.    Replace  damper  if any leaks are found. NOTE:  The damper cannot be repaired. 2. Check for housing distortion with a micrometer as follows: a. Remove paint off damper at the four points shown in Figure 19. b. Measure depth of damper housing at each point. c. If any of the points (A, B, C, D) vary more than .002 in., it is necessary to replace the damper. NOTE:      Housing   distortion   can   result   in   damper leakage   or   improper   damper   functioning   if   outer housing contacts inertia mass (flywheel). CGES-185-3 PRINTED IN UNITED STATES OF AMERICA Page 10