SCREW-RECESS FLAT HEAD 3E6922 - Caterpillar

3408 ( 99U, 78Z ),
3408B ( 6NB ),
3412 ( 38S, 7DB, 60M, 81Z ) Industrial, Marine, And Generator Set EnginesDescription of Change: New power takeoff groups for the above engines use an adapter that has an added mounting bolt and new dowels. This allows the front power takeoff adapter to more easily meet SAE specifications for face and bore runout. The new adapter uses two sets of adjustable dowels that are bolted on with a socket head bolt through each set of dowels. An additional mounting bolt has been added to the top of the adapter. The dowels, one bolt-on and one threaded, replace the former one-piece dowels. See illustration.
Front Power Takeoff Adapter.Adaptable To: The new dowel and bolt set is a direct replacement for the former solid dowels used in earlier adapters on the above engines. Use the following procedure to check face and bore runout. On earlier engines, substitute two crankshaft flange bolts for the single mounting bolt. Procedure To Check Face And Bore Runout:
1. Mount the adapter housing.2. Tighten the dowels and mounting by hand.3. Check for face and bore runout (refer to Service Manual).4. Use a soft hammer to bump the adapter housing into final position.5. Tighten the dowels and mounting bolt. After the adapter housing is mounted and positioned initially, the housing can then be removed without disturbing the dowel location. To remove the housing, remove the mounting bolts but do not loosen the dowels. This will maintain the position of the housing when it is reinstalled.