PLATE 6T9272 - Caterpillar

TECHNICAL INFORMATION BULLETIN August 8, 2005
Off-Highway Trucks 769B (99F1-UP)
769C (01X1-UP)
769D (5SS1-UP, 5TR1-UP, BBB1-UP)
770 (BZZ1-UP)
771 (3BJ1-UP)
771D (6JR1-UP, 6YS1-UP, BCA1-UP)
772 (80S1-UP, RLB1-UP)
773 (63G1-UP)
773B (63W1-UP)
773D (7CS1-UP, 7ER1-UP)
773E (BDA1-UP)
775 (7XJ1-UP)
775D (6KR1-UP, 8AS1-UP)
775E (BEC1-UP)
777 (84A1-UP)
777B (4YC1-UP)
777C (4XJ1-UP, 8JL1-UP)
777D (3PR1-UP, AGC1-UP, DCB1-UP)
777D HAA (2YW1-UP, AGY1-UP)
SMCS CODE 4312SUBJECT: Troubleshooting Procedures Required on Off-Highway Trucks Steering System Before Removing and Repairing the Hand Metering Unit (HMU).
PROBLEM:
Metering pump 129-2372 was replaced by 192-4286. Metering pump 129-2366 was replaced by metering pump 195-6617. Some Off-Highway Truck operators are still experiencing "hard-steer" during the operation of the machinery with the new metering pumps.
SOLUTION:
Before removing the HMU, verify that the system settings are correct by troubleshooting the steering system. Troubleshoot the steering system by performing the test and adjust procedures provided below for your machine. Perform the procedures in the order that they appear below.
Steering System, Test and Adjust, "Relief Valve (Primary Steering Backup) ? Test and Adjust"
Steering System, Test and Adjust, "Piston Pump (Steering) Pressure ? Test and Adjust"
Performing these procedures should correct the steering problem. Before removing the metering pump, please call Nate Weber, Caterpillar Hydraulics and Hydraulic Systems, at 815-729-5730 or Tyrone Jungjohann, at 815-729-5621 in order to provide additional feedback.
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