FRAME GP-TRACK ROLLER 4507091 - Caterpillar

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.
This Program must be administered as soon as possible. When reporting the repair, use "PI3736" as the Part Number, "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 "PI3736" as the Part Number, "7751" as the Group Number, "96" as the Warranty Claim Description Code, and "Z" as the SIMS Description Code.
Completion Date
September 30, 1995Termination Date
March 31, 1996Problem
The signal relief valves may fail as a result of system contamination on certain 350, 350L, 375 and 375L Excavators. Contaminants are caught on the seat of the valve causing leakage. Bleeding the pilot lines (on 350, 350L, 375 and 375L) and adjusting margin pressure (on 350 and 350L only) may improve performance.
Affected Product
Model & Identification Number
350 (2ZL139-159, 2ZL161-167 7RK144 , 7RK214-216, 7RK219, 7RK220, 7RK227, 7RK231)
350L (9DK120-123, 9DK130, 9DK138, 9DK140, 9DK141 3ML94-177 , 3ML179-197, 3ML199-409)
375 (8XG130-131, 8XG136, 8XG141-142, 8XG150, 8XG155, 8XG160-162, 8XG165, 8XG171 8WJ58-84 )
375L (1JM37-117 6RL36-38 , 6RL40, 6RL44)
Parts Needed
Action Required
See the attached procedure.
Owner Notification
U.S. and Canadian owners will receive the attached Owner Notification.
Service Claim Allowances
This is a 5 hour job.
U.S. and Canadian Dealers Only - Eligible dealers may enter a Type 2 SIMS Report.
Parts Disposition
Handle the parts in accordance with your Warranty Bulletin on warranty parts handling.
MAKE EVERY EFFORT TO COMPLETE THIS PROGRAM AS SOON AS POSSIBLE.
Attach.(1-Owner Notification)(2-Rework Procedure)Copy Of Owner Notification For U.S. And Canadian Owners
Rework Procedure
Rework Procedure for 350 and 350L Excavators
1. Remove both signal relief valves. These valves should be replaced with new 1170478 Signal Relief Valves. Maximum tightening specification for the valve is 50 Nm (37 lb/ft). See Illustration 1.2. Replace the 6E1761 or 1116873 Travel and Auxiliary (Heavy Lift) Signal Relief Valves and replace with 1175270 Signal Relief Valves. See Illustration 1.3. After installing the signal relief valves:A. Adjust line relief valves per the Service Manual.B. If the customer has been dissatisfied with modulation (implement response time), see the section at the end of this rework procedure on "350/350L Margin Pressure". Skip to Step C if there are no modulation complaints.C. Adjust the signal relief pressures per the Service Manual.D. Bleed the pilot system per the attached procedure. If the machine is equipped with a heavy lift circuit, adjust it per the Service Magazine dated May 16, 1994.
350/350L Signal Relief Valve Chart
Illustration 1Rework Procedure for 375 and 375L Excavators
1. Remove both signal relief valves and replace with a new 1170478 and a 1175269 Signal Relief Valve (see Illustration 2). Maximum tightening specification for the valve is 50 Nm (37 lb/ft).2. Replace the 6E1761 Valve (Travel Relief) at the same time. This valve should be replaced with a new 1175270 Valve (see Illustration 2).3. After installing the signal relief valves, adjust the line relief valves per the