CYLINDER HEAD GP 1152323 - Caterpillar

--------------- END SUPPLEMENT ---------------Description of Change: This article supersedes the article with the same title on Page 17 of the May 17, 1993 issue. 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 Illustration 5. The new clamps and brackets will help prevent vibrations from damaging the fuel injection lines. The correct clamp and bracket hardware and locations are very important for improved fuel line durability.
Adaptable To: The new components in the 3408 (48W) Machine Engine fuel injection lines groups are identified in Illustration 1 and Chart E. The new components in the 3408 Industrial (67U), Marine (99U), and Generator Set (78Z) Engines fuel injection lines groups are identified in Illustration 2 and Chart F. All the new components are in effect as shown in Chart A. The new components in the 3412 (73W, 1DB) Machine Engine fuel injection lines groups are identified in Illustration 3 and Chart G. The new components in the 3412 Industrial (38S), Marine (60M, 7HG), and Generator Set (81Z, 5AG) Engines fuel injection lines groups are identified in Illustration 4 and Chart H. The new fuel injection lines are in effect as shown in Chart B. The new clamps and brackets are in effect at later serial number breaks than the fuel injection lines.
The new 3408 components are adaptable as shown in Chart C. The new 3412 components are adaptable as shown in Chart D.
Illustration 1. Location of 3408 Machine Engine (48W) fuel line group components.
Illustration 2. Location of 3408 Industrial (67U), Marine (99U), and Generator Set (78Z) Engine fuel line group components.
Illustration 3. Location of 3412 Machine Engine (73W, 1DB) fuel line group components.
Illustration 4. Location of 3412 Industrial (38S), Marine (60M, 7HG), and Generator Set (81Z, 5AG) Engine fuel injection line group components. New wider [19.0 mm (.75 in) versus 12.0 (.47 in) fuel line clamp assemblies are used on 3412 engines. See Illustration 3 and Chart G, and Illustration 4 and Chart H for the locations and identification of 4P3677, 4P3678, 7C6591, and 7C7747 Clamps. The wider clamps are required for additional fuel line support.
Illustration 5. Location of Undercut Hex (A) and Collar (B) on the new fuel lines.
Illustration 6. Section B-B. Components of 6I4813 Clamp Kit. (31) 1022731 Spacer Bar. (32) 6I4811 Damper. (33) 6I4812 Clamp. (34) 7M2931 Screw. (35) 6D3848 Washer.A new formed viton damper clamp (3412 ONLY) is used on the fuel line assemblies for the number 4 and 6 cylinders. See Illustrations 3 and 4 (Section B-B) for the location and Illustration 6 for the new clamp component identification.
Illustration 7. Section C-C. Location of