Usage:
CONFIDENTIAL TIBU3672-00
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TECHNICAL INFORMATION BULLETIN |
SEPTEMBER 25, 2002 |
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PRODUCT FAMILY(S) |
D11R (7PZ1-610) D11R CARRYDOZER (AAF1-195) |
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Component Code(s) 4151 |
SUBJECT: PREVENTING CRACKS IN THE REAR TRACK ROLLER FRAME
PROBLEM:
Cracking has been reported near the pivot shaft housing on rear track roller frames equipped with wrapper plates. The cracks occur in the casting at the toe of the fillet weld at the rear of the wrapper plate.
SOLUTION:
Illustration 1
The welds along seam (A) between the casting and wrapper plate (B) should be checked for adherence to the weld criteria below. The area should also be inspected for cracks. Cracks that are ignored will eventually propagate through the casting and leak oil.
WELD CRITERIA:
Illustration 2a Illustration 2b Illustration 2c
Unacceptable Acceptable Preferred
Illustration 2 shows the cross section of the fillet welds along the seam between the roller frame and the wrapper plate:
Illustration 2a: Unacceptable. Weld toe less than 90 degrees (rollover/undercut).
Illustration 2b: Acceptable. Weld toe at 90 degrees.
Illustration 2c: Preferred. Weld toe greater than 90 degrees, radius at least 3 mm (1/8 inch).
REQUIRED ACTION:
If no cracks exist and weld is acceptable, no further action is required.
If no cracks exist and weld is unacceptable, an additional small weld pass is recommended to blend the weld into the casting. Maximum penetration is not required for this final weld as it is not structural in nature.
If cracks exist or an oil leak is evident, contact a Product Analyst for further repair recommendations.
COPYRIGHT 2002 CATERPILLAR
ALL RIGHTS RESERVED