SHAFT AS-IDLER 1458503 - Caterpillar

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 be administered either before or after a failure. In either case the decision whether to apply the Program is made by the dealer. When reporting the repair, use "PS4987" as the Part Number and "7755" as the Group Number. If administered before failure, use "56" as the Warranty Claim Description Code and use " T" as the SIMS Description Code. If administered after failure, use "96" as the Warranty Claim Description Code and use "Z" as the SIMS Description Code.
Termination Date
June 30, 1994Problem
The timing advance mechanism on certain 3406B and 3406C Truck Engines may not always operate properly causing complaints of low power, high fuel consumption, or unusual engine noises.
Affected Product
Model & Identification Number
3406B (4CK1-10008, 4CK10010-10014, 4CK10016-10019, 4CK10021-10026, 4CK10028-10062, 4CK10064-10070, 4CK10072-10075, 4CK10077-10260, 4CK10262, 4CK10265, 4CK10267-10271, 4CK10273-10277, 4CK10279, 4CK10283, 4CK10286, 4CK10288, 4CK10290-11219, 4CK11221, 4CK11223-11354, 4CK11356-11456, 4CK11458-11938, 4CK11940-11942, 4CK11944-12081, 4CK12083-14613, 4CK14615-15434)
3406B & 3406C (2EK1-Up)
Check SIMS serial number data to determine if the engine timing advance mechanism has previously been reworked in accordance with a marketing program. If the timing advance has been reworked, this program does not apply.
Parts Needed
1 - 8C4304 Ring1 - 2H3931 Seal2 - 8N4524 Gasket4 - 5S2671 Bolt (as required)1 - 2W0459 Gasket1 - 2W3621 Housing Assembly (as required)1 - 2W3624 Cover Assembly (as required)2 - 1072961 Washer1 - 1084511 Clamp AssemblyAction Required
See attached rework procedure.
Service Claim Allowances
Parts Disposition
Handle the parts in accordance with your Warranty Bulletin on warranty parts handling.
Attach. (1-Rework Procedure)Rework Procedure
1. Remove the timing solenoid (BTM). Remove the timing advance housing, bellcrank assembly, and timing sensor as a unit. See the Disassembly and Assembly module of the Service Manual.2. Remove the 3P3547 Retaining Ring, the 4P3500 Sleeve Assembly and the two 2W3632 Support Washers from the 4P3384 Spool. The retaining ring and the two washers will not be reused. If access is tight due to the chassis configuration, the 4P3384 Spool and 2W3636 Retainer Sleeve can be removed from the carrier assembly. If you elect to do this, clean the threads in the carrier assembly and use four new 5S2671 Bolts and 9S3263 Thread Lock when installing the spool and retainer sleeve. Tighten these bolts to 2.5 N m (22 lb. in.).
3. Remove the two 2S9255 Bolts from the 1084511 Clamp Assembly.4. Sparingly apply 9S3263 Thread Lock to the threads of the 2S9255 Bolts to prevent it from getting between the mating surfaces of the clamp halves or on the spool when assembled.5. Loosely assemble the 1084511 Clamp Assembly.6. Install a 1072961 Support Washer, the 4P3500 Sleeve Assembly and then the other 107-2961 Support Washer on the 4P3384 Spool.7. Slide the 1084511 Clamp Assembly over the end of the 4P3384 Spool. After applying the thread lock to the bolt threads, install the clamp assembly on the spool within 5