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 "PS4053" 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
May 31, 1998Problem
The rear hub may wear against the housing due to the increased duo-cone face load on certain 789, 789B, 793, and 793B Trucks equipped with the 116-5241 Retainer (789) or 118-8395 Retainer (793). Orifice plates have been added to the rear brake cooling return lines. This modification will increase the internal pressures and reduce the amount of brake hub wear on the housing.
Affected Product
Model & Identification Number
Group 1
789 (9ZC1-677)
789B (7EK1-282)
Group 2
793 (3SJ1-56)
793B (1HL1-204)
Parts Needed
Group 1
Group 2
Action Required
Remove the brake cooling lines at the hydraulic tank and install orifice plates and longer bolts.
Reference Service Magazine dated August 19, 1996, Page 9 "New Orifice Plate To The Rear Brake Cooling Return Oil Line Significantly Reduces Hub Wear".
Service Claim Allowances
NOTE: This is a 2-hour job. If there has been a previous repair, Part age/hours apply.
Parts Disposition
Handle the parts in accordance with your Warranty Bulletin on warranty parts handling.