PRODUCT IMPROVEMENT PROGRAM FOR REPLACING THE GENERATOR SET COUPLING 5N-3765 WITH A 296-8050 ON CERTAIN G3520C GENERATOR SETS WHEN THE MAXIMUM AMBIENT TEMPERATURE NEAR THE DAMPER GROUP IS LESS THAN 50C. Caterpillar

PRODUCT IMPROVEMENT PROGRAM FOR REPLACING THE GENERATOR SET COUPLING 5N-3765 WITH A 296-8050 ON CERTAIN G3520C GENERATOR SETS WHEN THE MAXIMUM AMBIENT TEMPERATURE NEAR THE DAMPER GROUP IS LESS THAN 50C.

Usage:

REBE1391-01

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07Jun2007

(Revised 29Jun2007)

U-239

A-196

D-204

O-220

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*Priority*	PRODUCT IMPROVEMENT PROGRAM FOR REPLACING THE GENERATOR SET COUPLING 5N-3765 WITH A 296-8050 ON CERTAIN G3520C GENERATOR SETS WHEN THE MAXIMUM AMBIENT TEMPERATURE NEAR THE DAMPER GROUP IS LESS THAN 50C.
3252 4450 4456		PI31278

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NOTE:

This Program must be administered as soon as possible. When reporting the repair, use "PI31278" as the Part Number and "7751" as the Group Number, "56" as the Warranty Claim Description Code and "T" as the SIMS Description code. Exception: If the repair is done after failure, use "PI31278" as the Part Number, "7751" as the Group Number, "96" as the Warranty Claim Description Code, and "Z" as the SIMS Description Code.

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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.

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NOTE:	This Revised Service Letter replaces the June 7, 2007 Service Letter. Changes have been made to the Required Parts.

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COMPLETION DATE	TERMINATION DATE
31Dec2007	30Jun2008

PROBLEM

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Generator Set Coupling 5N-3765 needs to be replaced with Generator Set Coupling 296-8050 on certain G3520C 1500rpm Generator Sets. The existing Generator Set Coupling can get damaged because of excessive torsional vibration levels.

AFFECTED PRODUCT

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Model	Identification Number
G3520C	CWW00256-00258, 262-264, 277, 283-286 GZK00151-00166 GZN00218-00220, 227, 229, 231-232

PARTS NEEDED

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Qty	Part Number	Description
8	4M6953	WASHER-HARD
12	8D7942	BOLT-12 POINT HD
8	9X2119	BOLT-12 POINT HD
1	2490059	COUPLING-INNER
1	2968049	COUPLING-OUTER

ACTION REQUIRED

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Prior to performing this update, the ambient air temperature around the damper must be measured or known. Measure the ambient air temperature within 3-6 inches of the front face of the damper guard at the 12, 3, 6, and 9 o'clock positions. The average ambient air temperature should not exceed 50C at full rated conditions. Temperature measurements should be taken only after the engine and surrounding temperatures have stabilized over an 8-10 hour period.

For customer sites with higher than 50C ambient air temperature around the damper, the customer must improve the air flow around the damper, or reduce the overall air temperature in the engine room. The air temperature around the damper should be measured again, as explained above, whenever system changes are made. If the air temperature around the damper cannot be reduced below 50C, please work through your Dealer Technical Communicator to contact the DSN (Dealer Solution Network) for availability of options to compensate for high ambient temperature conditions. Do not proceed with implementation of this Service Letter until ambient conditions are reduced below 50C, or if a component option is approved.

NOTE: Changes in the outside ambient air temperature will affect the air temperature around the damper. If the outside ambient air temperature is below the maximum expected temperature for your region, then the difference between the maximum expected outside ambient temperature and the current outside ambient air temperature must be added to the air temperature measured around the damper. This adjusted temperature value will represent the maximum ambient air temperature expected around the damper when the outside ambient air temperature reaches the maximum expected level.

If the ambient temperature around the damper is less than 50C, proceed with the attached rework procedure to complete the requirements of this service letter.

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Image1

OWNER NOTIFICATION

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U.S. and Canadian owners will receive the attached Owner Notification.

SERVICE CLAIM ALLOWANCES

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Caterpillar		Dealer Suggested		Customer Suggested
Parts %	Labor Hrs%	Parts %	Labor Hrs%	Parts %	Labor Hrs%
100%	100%	0%	0%	0%	0%

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NOTE: This is a 5.0-hour job

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PARTS DISPOSITION

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Handle the parts in accordance with your Warranty Bulletin on warranty parts handling.

MAKE EVERY EFFORT TO COMPLETE THIS PROGRAM AS SOON AS POSSIBLE.

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COPY OF OWNER NOTIFICATION FOR U.S. AND CANADIAN OWNERS

XYZ Corporation
3240 Arrow Drive
Anywhere, YZ 99999

PRIORITY - PRODUCT IMPROVMENT PROGRAM FOR REPLACING GENERATOR SET COUPLING 5N-3765 WITH 296-8050

MODELS INVOLVED - CERTAIN G3520C GENERATOR SETS

Dear Caterpillar Product Owner:

A new coupling need to be installed on the products listed below. The coupling is being replaced to improve the reliability of the driveline. You will not be charged for the service performed.

Contact your local Caterpillar dealer immediately to schedule this service. The dealer will advise you of the time required to complete this service.

Please refer the dealer to their Service Letter dated 07Jun2007 when scheduling this service.

We regret the inconvenience this may cause you, but urge you to have this service performed as soon as possible to prevent unscheduled downtime.

Caterpillar Inc.

Identification #(s)

Attached to 07Jun2007 Service Letter

Rework Procedure

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Instructions for replacing the Caterpillar coupling with a new high inertia coupling.

1. Refer to the appropriate Service Manuals for safety instructions and additional details. Reference SEBU7681, RENR5980, & REHS0177.

2. Remove the generator set from operation by locking out the circuit breaker(s) and by removing battery power from the controls and the starter motor(s).

3. Make sure that the power cables and control wires connected to the generator have sufficient slack to allow the generator to be moved back from the engine. In most cases it will not be necessary to disconnect anything.

4. Unbolt the rubber boot retaining ring.

5. Remove the rubber boots.

6. Unbolt the generator from the rails and the engine flywheel housing.

7. Slide the generator back approximately 40 cm from the engine to gain access to the coupling components. Take care not to damage or mix up the shims under the generator feet.

8. Unbolt and remove the outer coupling element from the flywheel. Discard.

9. Unbolt and remove the inner element from the generator hub. Discard.

10. Clean any grease or dirt from the flywheel.

11. Install the new rubber element on the generator hub using the 9X2119 bolts with 4M6953 washers. Rotate the rubber element to line it up for insertion with the coupling ring. Tighten the bolts in a clockwise opposing pattern before using the same pattern to torque the bolts to 620 Nm (+/- 80 Nm).

12. Install the new coupling ring on the flywheel. Use the new washers supplied with the coupling ring and the 8D7942 bolts. Tighten the bolts in a clockwise opposing pattern before using the same pattern to torque the bolts to 215 Nm (+/- 40 Nm)

13. Slide the generator forward inserting the rubber element into the coupling ring.

14. Insert the original stack of shims at each generator mounting foot.

15. Align the generator set. If the generator set was properly aligned before starting on the coupling replacement only minor adjustments, if any, will be needed.

16. Check engine crankshaft deflection.