ENGINE AR 7N3199 - Caterpillar

This Program can only be administered after a failure occurs. The decision whether to apply the Program is made by the dealer. When reporting the repair, use "PS50105" as the Part number and "7755" as the Group Number. Use "96" as the Warranty Claim Description Code and use "Z" as the SIMS Description Code.
This Revised Service Letter replaces the August 15, 2000 Service Letter. Changes have been made to the Service Claim Allowances.
Termination Date
August 31, 2001Problem
Under certain conditions when the bucket cylinder is fully retracted, the top pin joint of the bucket may go over center with the mating link assembly. The bucket may then become locked in this position and inoperable.
Affected Product
Model & Identification Number
M312 (6TL1-755)
M315 (7ML1-548, 7ML550-794, 7ML796-824, 7ML806-1270)
M318 (8AL1-138, 8AL140-1079, 8AL1081-1347, 8AL1349-1827, 6ES1-236, 8SS1-458)
Parts Needed
M312
3 - 5W2817 Fitting-Grease2 - 0931434 Seal-Lip Type2 - 1144850 Seal-Lip Type1 - 1665449 Linkage As-Bearing2 - 1691360 Pin As1 - 1691366 Link AsM315
2 - 1R6229 Pin As3 - 5W2817 Fitting-Grease2 - 0931433 Seal-Lip Type2 - 0931434 Seal-Lip Type1 - 1507779 Linkage As-Bearing1 - 1660530 Link AsM318
2 - 1R6229 Pin As3 - 5W2817 Fitting-Grease2 - 0931433 Seal-Lip Type2 - 0960854 Seal-Lip Type1 - 1616551 Linkage As-Bearing1 - 1616555 Link ASAction Required
Linkage over centering may be caused by either excessive pin play in the bucket linkage group or an attachment component (bucket or quick coupler) that does not comply with the design requirements of the linkage. This program will address only excessive pin play within the two link assemblies of the bucket linkage group.
To determine if this program should be applied to resolve linkage over centering proceed as follows:
During disassembly and assembly of the components addressed in the following instructions, follow "Remove and Install Bucket Linkage Group" instructions in the Disassembly and Assembly (D&A) section of the Service Manual.
Measure the center-to-center distance between the two pins of the bucket (or quick coupler). This distance is shown as dimension 'A' in Illustration 1.
Compare the distance measured to the corresponding value given in Table 1. If the distance measured is less then the value in Table 1, the bucket (or quick coupler) does not comply with the design requirements of the linkage and should be replaced with one that meets the Table 1 specification.
If the distance measured is either equal to or greater then the value in Table 1, link assemblies B and C in Illustration 1 should be replaced using parts with the specified Repair Kit.
Excessive wear in the pin joint between the bucket cylinder and stick bracket may also contribute to the over center condition. (Reference Pin D, Illustration 1) The suggested allowable diameter of the bore