Excavator Komatsu PC160-7 PC160-8 PC180-7 Main Control Valve Assembly 723-57-16100 723-57-16103 723-56-16101 Common Faults & Symptoms Slow and weak machine movements Weak operation of single actuator (boom / arm / bucket / swing / travel) Jerky and vibrating movement Interference during combined operation, poor flow merging External leakage of main control valve, oil seepage and oil leakage on valve body Severe internal leakage, rapid pressure drop and poor pressure retention