Usage:
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 "PS4349" 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
February 28, 1999Problem
The drive plates in certain generator sets have been assembled using an incomplete 2N7025 Plate Assembly. A complete plate assembly will need to be installed.
Affected Product
Model & Identification Number
3304B (9HK332-379)
Parts Needed
Action Required
See the attached rework procedure.
Service Claim Allowances
NOTE: This is a 4-hour job.
Parts Disposition
Handle the parts in accordance with your Warranty Bulletin on warranty parts handling.
Attach.
- (1-Rework Procedure)
Rework Procedure
NOTE: This rework procedure requires moving the generator backwards to allow support by the base crossmember. Therefore, all pipe work and wiring not shown in this procedure must be given adequate slack or be disconnected. Make sure all Safety procedures are followed and disconnect electrical power to the system by removing the battery negative cable from the batteries.
Preparation Prior To Disassembly
1. Remove the bulkhead panel by removing the bolts securing the bulkhead panel to the enclosure.
2. Remove the bolts securing the generator barrel guard to the generator and remove the guard from the enclosure.
Disassembly Of Generator From Engine
1. Remove the bolts securing the generator screen and remove the screen.
2. Remove the earth ground bolt from the pad on the generator base.
3. Turn the engine over to Top Dead Center (TDC). Remove the top flywheel to generator drive plate bolt and install a guide bolt. Remove the remaining flywheel to generator drive plate bolts.
4. Remove the generator foot bolts on each side. Using hydraulic jacks, properly supported underneath by base crossmembers to prevent damage to the base, one under each side on the flywheel housing mounting pad, raise the generator a maximum of 13mm clearance at the generator foot. Place supports under the flywheel housing to support the weight of the engine and avoid supporting the engine on the plug in the bottom of the flywheel housing.
5. Fit slings around the underside of the generator just in front and in back of the foot.
6. Take up slack in the slings.
7. Remove the flywheel housing bolts and take up the weight of the generator using the slings. The generator can now be guided away from the engine. Provide support at the base crossmember for the generator foot.
Remove And Install New Drive Plates
NOTE: Prevent rotor from turning during this sequence.
1. Remove bolts on drive plate to generator rotor and discard.
2. Remove flex plate and discard. (Retain shims on shaft)
Reassemble
1. All contact surfaces of the engine, the coupling, and the generator must be completely clean.
2. Install new 2N7025 Plate Assembly (this assembly has six individual plates) and shims. Refer to Special Instructions SEHS7259-02 to assure proper crankshaft endplay and generator bearing position.
3. Install 9S1366 Bolts and 5P8245 Washers and tighten bolts to 70 N·m.
4. Move the generator gently towards the engine until the guide bolt engages the TDC hole in the drive plate and fan, raising the generator to center the generator rotor and continue to gently move the generator toward the engine completely engaging the generator housing into the engine flywheel housing bore.
5. Install the flywheel housing to generator housing bolts and tighten after assuring there is no gap between the housings before final tightening to a torque of 70 N·m.
6. Install the drive plate to flywheel housing bolts after removing the guide bolt and apply a standard torque of 105 N·m.
7. Remove the slings and lower the jacks under the flywheel housing and insert the generator foot bolts. Check to make sure that the generator feet are aligned properly with the mounting holes. Install the nuts and washers and tighten to a torque of 370 N·m using a 1- inch universal socket.
NOTE: This is a critical torque.
8. Install the generator screen. Install the earth ground bolt and strap to the pad on the base and tighten. Return any wiring harnesses to their original positions and ty-wrap them in place. Install the generator barrel guard and tighten the ten bolts to 18 N·m. Install the bulkhead panel and tighten the ten bolts to 8 N·m.