PRODUCT SUPPORT PROGRAM FOR IMPROVING THE SERVICE LIFE OF THE WELD ON THE FRONT FRAME HITCH BOSS ON CERTAIN 120M AND 12M MOTOR GRADERS Caterpillar

PRODUCT SUPPORT PROGRAM FOR IMPROVING THE SERVICE LIFE OF THE WELD ON THE FRONT FRAME HITCH BOSS ON CERTAIN 120M AND 12M MOTOR GRADERS

Usage:

REBE7893-00

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20Dec2011

D262
U060
U062
U070
U135
U139
U143

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Before/After (Limited distribution)	PRODUCT SUPPORT PROGRAM FOR IMPROVING THE SERVICE LIFE OF THE WELD ON THE FRONT FRAME HITCH BOSS ON CERTAIN 120M AND 12M MOTOR GRADERS
7051 1273		PS43468

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NOTE:

This Program must be administered either before or after failure. In either case the decision whether to apply the Program is made by the dealer. When reporting the repair, use "PS43468" as the Part Number and "7755" as the Group Number. If administered before failure, use "56" as the Warranty Claim Description Code and "T" as the SIMS Description code. If administered after failure, use "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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TERMINATION DATE

31Dec2013

PROBLEM

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The existing front frame hitch boss weld can fail on certain 120M and 12M Motor Graders. If the existing weld fails it can lead to cracks in the parent material of the frame and ultimately cause a complete frame failure.

AFFECTED PRODUCT

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Model	Identification Number
120M	B9C00373
12M	B9F00013, 87, 95, 154, 224, 381

PARTS NEEDED

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No parts needed for this program

ACTION REQUIRED

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Refer to the attached Rework Procedure.

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SERVICE CLAIM ALLOWANCES

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Product smu/age whichever comes first	Caterpillar		Dealer Suggested		Customer Suggested
Product smu/age whichever comes first	Parts %	Labor Hrs%	Parts %	Labor Hrs%	Parts %	Labor Hrs%
0-12000 hrs, 0-72 mo	100.0%	100.0%	0.0%	0.0%	0.0%	0.0%

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NOTE: This is a 11.0-hour job
An additional 80 hours of labor are allowed for machines that need to have cracks repaired.

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PARTS DISPOSITION

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

Rework Procedure

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Required Tools List:

1. Suitable container to drain fuel into for reuse or disposal.
2. High speed pneumatic rotary pencil grinder - 20,000 rpm minimum
3. Compressed air - 620 kPa (90 psi)
4. Tungsten carbide burr (conical shape) - end diameter of 10mm
5. Radius gauges and bridge cam gauge for inspection
6. Dye penetrant for crack inspection
7. Appropriate personal protective equipment

1. Ensure that the machine is properly parked for service. Refer to RENR8459, Troubleshooting, "Machine Preparation for Troubleshooting". The machine frame will not need to be separated for this procedure. Also, the machine should not be articulated for this procedure.

2. Remove the fuel tank from the machine. Refer to KENR6418, Disassembly and Assembly, "Fuel Tank - Remove".

3. Ensure that the area around the front frame hitch boss and weld is clean and free of all debris and contaminants. All paint must be removed from the front facing half of the boss weld and the immediate area around the boss weld on the front frame parent material.

4. Using a dye penetrant inspect the boss weld for any sign of cracking. If there is any sign of cracking present, please contact Caterpillar through the Dealer Solutions Network (DSN) for the appropriate rework procedure. In the service request, please include photos of the crack and any details as to the size and depth of the crack.

If no crack is detected, proceed with the Rework Procedure in this Service Letter.

NOTE: The profile or geometry of the weld toe controls the fatigue performance of fabricated structures. These fabricated structures have attachments that are welded to highly stressed members. Fatigue performance improvement can be achieved through alteration of the original toe profile by several post weld treatment options. This procedure describes a method of using a mechanical means in order to remove adverse profiles and adverse stress risers. This method creates a smooth transition from one component to the next component.

Image1.6.1

Image1.6.2

5. Place the conical burr tip directly over the weld toe. The axis of the tool should be maintained at approximately 45 degrees to the base metal. The tip should also maintain a 45 degree angle to the direction of travel. Refer to Images1.7.1 and 1.7.2.

Image1.7.1

6. Grinding should extend to a depth of 0.5mm below the last visible traces of the weld toe. This should result in a grinding depth of 0.8mm to 1.0mm. The resulting ground surface should be smooth, and the grinding marks should be 90 degrees to the weld, not parallel. There should be no visible traces of the original weld toe when the area is viewed with a magnifying glass. Perform this grinding procedure to the front 1/3 to 1/2 of the boss weld. Refer to Image1.8.1 for recommended area to perform the procedure on. There is sufficient clearance to perform this procedure without separating the machine frame or articulating the machine.