09300-06661 PUMP ASSY, INJECTI Denso Cross

Caterpillar: Confidential Yellow
The information supplied in this service letter may not be valid after the termination date of this program. Do not perform the work outlined in this Service Letter after the termination date without first contacting your Caterpillar product analyst.
This Program can only be administered after a failure occurs. The decision whether to apply the Program is made by the dealer. When reporting the repair, use "PS0642" as the Part Number and "7755" as the Group Number. Use "96" as the Warranty Claim Description Code and use "Z" as the SIMS Description Code.
Termination Date
January 31, 1994Problem
The fuel injectors may fail on certain Challenger 75 Tractors and 3176 Truck Engines.
Affected Product
Model & Identification Number
Challenger 75 (4CJ1-406)
3176 (2YG1-Up; 7LG1-4822)
Parts Needed
Use the following parts in quantities needed to perform repairs. The application of each injector listed is noted. Use remanufactured injectors, unless it is not available.
0R3397 Injector Grp. (4P9510 if remanufactured is not available for 7LG 250-300 HP)0R3398 Injector Grp. (4P9520 if remanufactured is not available for 7LG 325 HP and Challenger 75 4CJ1-406)0R3399 Injector Grp. (4P9610 if remanufactured is not available for 2YG 250-275 HP)0R3400 Injector Grp. (4P9620 if remanufactured is not available for 2YG 300-325 HP)9X7317 Seal (injector tip O-ring)9X7557 Seal (injector upper O-ring)9X7722 Seal (injector lower O-ring)336044 Seal (injector thrust-pad-retaining O-ring)Action Required
See attached Rework Procedure.
Service Claim Allowances
Challenger 75 Tractors
This is a 2.5-hour job. Add 0.2 hours for 1st injector diagnostic test and 0.1 hours for each additional injector test. Add 1.2 hours for first injector sleeve replaced and 0.7 hours for each additional sleeve replaced.
3176 Truck Engines
Parts Disposition
Handle the parts in accordance with your Warranty Bulletin on warranty parts handling.
Attach. (1-Rework Procedure)Rework Procedure
1. Isolate the problem to the individual injector causing the problem. For this program only the failed injector(s) is covered so it is important to isolate the individual injector(s) causing the problem.A. For fuel dilution of the engine oil, first attempt to find the leak by pressurizing the low pressure system with the hand priming pump and the return line blocked off. Visually inspect each injector for leaks. It is also important to inspect the cylinder head casting for leaks around the injector bore, in the hold down bolt holes and along the gallery which crosses the camshaft compartment. If no leaks are found the injectors should be removed and leak tested using the 1U6661 Pop Tester. Drain the fuel manifold by removing the lower plug at the rear of the manifold. Remove the suspect injector(s). Test the injector(s) with the 1U6661 Pop Tester following the procedures in Special Instructions SEHS8867. Be sure to activate the solenoid valve and stroke the injector to create high pressure inside the injector when inspecting the high pressure plug for leaks. The plug is located at the base of the forged body.
The leak-down rate is a measure of plunger clearance leakage and should be checked when looking for fuel leaks.
Some small amount of leakage at the terminal post is permitted. Refer to Service Magazine September 21, 1991