Five Common Problems and Fault Analysis of Komatsu Excavator

01. The failure of working device, walking and turning speed of Komatsu excavator hydraulic system is low or weak, which may be caused by the following reasons:

◉ PC valve is poorly adjusted.

◉ LS valve assembly is poor.

◉ PC valve assembly is damaged.

◉ The hydraulic components of the output circuit of the pressure reducing valve are in fault

◉ Plunger pump failure.

◉ The servo piston of the plunger pump is faulty.

◉ The adjustment of the main overflow valve is not correct.

◉ The unloading valve does not operate properly.

◉ The main overflow valve is damaged.

Through fault analysis, the following solutions are obtained:
◉ Adjust or repair PC valve

◉ Check and repair LS valve

◉ Repair PC valve

◉ Repair the hydraulic components of the output circuit of the pressure reducing valve or replace the hydraulic components of the output circuit of the pressure reducing valve

◉ Overhaul the plunger pump

◉ Repair or replace the servo piston of the plunger pump

◉ Readjust the main overflow valve

◉ Adjust or repair the unloading valve

◉ Maintenance of main overflow valve

02. There are three common causes of oil burning failure of Komatsu excavator:

◉ Air filter of excavator is dirty

◉ Blowby of excavator engine

◉ The excavator oil is not replaced or used as normal

Solution to oil burning problem of Komatsu excavator:

◉ Clean and replace the air filter of excavator regularly

◉ Maintenance of excavator engine

◉ Use excavator oil according to regulations and match with excavator oil

03. Running deviation of Komatsu excavator

Cause 1: the possible causes of deviation during normal walking are:

◉ Pressure reducing valve failure.

◉ The valve element of the main operating valve acts badly.

◉ The travel motor assembly is faulty.

◉ LS valve is damaged.

◉ PPC valve is damaged.

◉ The travel pressure compensation valve is faulty. 

According to reason 1, the following solutions are obtained:

◉ Overhaul the pressure reducing valve

◉ Overhaul the main operating valve spool

◉ Overhaul the walking motor

◉ Service LS valve

◉ Repair the PPC valve

◉ Repair the traveling pressure compensation valve

04. Komatsu excavators after a period of time, the machine will have "in the process of use can not walk"

Causes:

◉ The oil filling valve in the main operating valve is not working properly.

◉ Safety valve failure of walking motor.

◉ Poor terminal transmission.

◉ Damaged walking motor.

Solutions:

◉ Repair the oil valve.

◉ Check the safety valve of walking motor.

◉ Overhaul and adjust the terminal drive.

◉ Overhaul the walking motor.

05. Komatsu excavators after a period of time, there will be "walking fatigue (or slow speed)" failure.

Causes:

◉ The CO valve is out of order.

◉ CO cancellation solenoid valve has a fault.

◉ Setting pressure drop of main overflow valve.

◉ Class 2 overflow solenoid valve has a fault.

Solutions:

◉ Overhaul the CO valve.

◉ Check the CO cancel solenoid valve.

◉ Check whether the setting pressure of the main overflow valve drops.

◉ Overhaul the level 2 overflow solenoid valve.