CARTRIDGE GP-TURBOCHARGER 4W2277 - Caterpillar

3408 (67U),
3412 (38S) Industrial Engines;
3408 (99U),
3412 (60M) Marine Engines;
3408 (78Z),
3412 (81Z) Generator Set EnginesDescription of Change: Improved fuel injection line assemblies, clamps, and brackets are used. The improved lines are manufactured from a stronger material that is more resistant to cracking caused by vibration and high injection pressures. A new stepped washer (collar) is used at each end of the improved line assemblies. The collars provide more support to each end of the lines. The improved fuel line assemblies can be identified by the undercut on the hex nut at each end of the line. See the illustration. The new clamps and brackets will help prevent vibrations from damaging the fuel injection lines.Adaptable To: The latest fuel injection line groups and there components are identified in the microfiche. See the microfiche for the applicable product.
(A) Undercut Hex. (B) Collar.New fuel line support brackets are used on engines that do not include aftercoolers. On 3408 engines these are the 4P8261 and 4P8385 Brackets. On 3412 engines this is the 6I0348 Bracket.
Before removing any clamps, mark their location with tape or some other non-damaging method. This will help insure that the clamps are reinstalled in the correct locations. Use a 6V6069 Torque Screwdriver or similar tool to tighten the clamp screws to a torque of 2.25 N m (20 lb in). Do not force fuel injection line ends into position and then begin to tighten the nuts on the ends of the lines. The result will be added strain on the lines. If needed, gently bend the lines by hand until the lines are the correct shape for the nuts to be easily started. Before tighten the nuts on the ends of the fuel injection lines, use the fuel priming pump to purge air from the fuel system. Tighten the fuel injection line nuts to a torque of 40 7 N m (30 5 lb ft). After starting the engine and checking for leaks, tighten the fuel injection line nuts again to a torque of 40 7 N m (30 5 lb ft).