Product Support Program For The Rework Of The Timing Advance Mechanism On Certain 3406B And 3406C Truck Engines Caterpillar

NOTE: 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.

NOTE: 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

Problem

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)

NOTE: 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 Ring

1 - 2H3931 Seal

2 - 8N4524 Gasket

4 - 5S2671 Bolt (as required)

1 - 2W0459 Gasket

1 - 2W3621 Housing Assembly (as required)

1 - 2W3624 Cover Assembly (as required)

2 - 1072961 Washer

1 - 1084511 Clamp Assembly

Action 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.

NOTE: 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.

NOTE: After applying the thread lock to the bolt threads, install the clamp assembly on the spool within 5 minutes before the thread lock hardens.

8. Make sure that the small lip in the bore of the clamp group goes into the groove in the spool for the 3P3547 Retaining Ring.

NOTE: Do not push the clamp group against the support washers and the sleeve assembly when tightening the bolts. The sleeve assembly must be free to rotate. Carefully lap/grind material from the sides of the sleeve assembly where it contacts the support washers if the sleeve assembly does not turn freely.

9. Tighten the 2S9255 Bolts to a torque of 1.2 ± .1 N·m (9 ± 1 in-lb) . It is acceptable for the installed clamp assembly to have a gap at each end.

NOTE: Steps 10 through 13 are a check of the pin depth of the 2W3624 Bell Crank Cover Assembly. Perform these steps before installing the parts removed in Step 1.

10. Remove the tool used to retain the bellcrank when the timing advance housing was removed.

11. Pull the bellcrank against its retaining ring and measure the endplay between the other side of the bellcrank and the bellcrank cover assembly. The end play must be no more than .635 mm (.025 in.).

12. If the end play is excessive, remove the bellcrank assembly from the 2W3621 Housing Assembly.

13. Set the bellcrank assembly on a flat metal surface with the pin facing up. Tap the pin into the cover until the endplay is between .127 and .635 mm (.005 and .025 in.).

NOTE: The pin has a tight press fit. Be careful NOT to drive the pin in too far. The bellcrank must be free to rotate. If the pin is driven too far, the 2W3624 Bellcrank Cover Assembly will have to be replaced since it is not possible to pull the pin back to the correct position without damaging the pin. Use a new 8C4304 Retaining Ring when assembling the 2W3623 Bellcrank Assembly.

14. Install the timing advance housing, bellcrank assembly, timing sensor as a unit. Then install the timing solenoid (BTM) as described in the Disassembly and Assembly module of the Service Manual. Seal the BTM, timing advance cover and bellcrank cover after final assembly.

15. Calibrate the timing sensor as described in the Testing and Adjusting module of the Service Manual.

16. Before removing the ECAP, start the engine and compare the Desired Timing Advance (DES TIM ADV) and Timing Advance (TIM ADV) readings on the status screen of the ECAP. The Timing Advance reading must be with ± .3 of a degree of the Desired Timing Advance reading.