What we should make sure is that there is no action in the whole vehicle. This type of fault is mainly caused by the blocked pump, safety locking lever and pilot oil circuit.
1. First determine whether there is really no action. Shut down the engine, restart and experiment again.
2. If there is still no action. Next, connect the manometer in "F" mode to check the pump pressure. It is found that the left and right pump pressures are above 330 kg, so the pump problem is eliminated temporarily.
3. Then, a spring piece at the hydraulic safety locking lever of the machine is broken. It is suspected that the switch at the start and stop lever can not be turned in place. Directly short circuit the switch and act, but there is still no response. Check the line and directly measure the two wires of the hydraulic lock solenoid valve with a multimeter. The voltage is more than 25V. It is normal, and the resistance of the solenoid valve is also normal. After the solenoid valve is directly removed and powered on, it is found that the solenoid valve core acts in place, and the problem of hydraulic lock solenoid valve is eliminated.
4. Finally, check the pilot system. The measured pilot pressure is about 35kg, which is normal. The problem of pilot pump is eliminated. Test drive again, still no action. At this time, it is suspected that there is a problem with the pilot pipeline. Directly disassemble the pilot pipeline of the bucket control valve on the main control valve, move the bucket arm, and no hydraulic oil flows out. It is determined that there is a problem with the pilot pipeline. The following work is to check the pilot oil circuit from the pilot pump. It is found that a pilot oil pipe behind the pilot multi-channel valve is blocked. After dredging, everything is normal.
