SPRING A07400129 - Caterpillar

TECHNICAL INFORMATION BULLETIN September 24, 2003
Wheel Skidders 515 (4LR1-99999)
517 (5WW1-99999, 6PW1-99999)
525 (1DN1-99999)
525B (3ZK1-99999)
527 (2RS-199999, 3DS1-99999,
4NS1-99999)
535B (AAE1-99999)
545 (2FZ1-99999)
Component Codes 5070-II 5084-QP 5455SUBJECT: ERRATIC HYDRAULIC SYSTEM OPERATION
PROBLEM: Erratic hydraulic system operation problems have been found on machines in the field. Erratic operation problems are difficult to troubleshoot. An erratic hydraulic system operation problem is an intermittent malfunction of the hydraulic system. Troubleshooting these problems often leads to replacing components that are not defective but will temporarily fix the problem. The symptoms of erratic system are:
Occasional loss of pump pressure when hydraulic oil is hot
2) Occasional slow down of implement function speed
3) Occasional inability to charge the brake accumulator
SOLUTION: Replace the pump control valve on the implement pump. Evidence has been found that the pump control on the implement hydraulic pump has caused erratic hydraulic system operation on wheel and track skidders. Replacing the pump control valve will correct many of the erratic system problems that are found on field machines.
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