What is an excavator missing arm?

Excavator arm drop is also called: boom, self-falling, drop pump, etc. Simply speaking, arm drop is actually a manifestation of the weakness of the excavator arm. When the boom is raised, it is controlled without the joystick. In some cases, the boom or forearm will automatically drop

When the excavator has a failure of the arm, it will also appear in different forms. The failure phenomenon can be roughly divided into the main arm, the small arm, the middle arm, the cold car and the hot car and so on.

7 common causes of arm drop failure:

1. Arm drop caused by hydraulic oil failure. If the car is cold and the car is hot, it is likely that there is a problem with the hydraulic oil.

2. The hydraulic cylinder of the excavator is faulty, especially when the oil seal of the oil cylinder is damaged or aged, resulting in internal leakage of the oil seal.

3. The valve hole of the distribution valve is blocked, the valve core is worn, the gap between the valve core is too large, and the main safety valve of the distribution valve is worn and damaged, resulting in large and small arms.

4. When the oil seal of the safety relief valve of the large and small arms is damaged, a certain leakage will be caused, which will also lead to the phenomenon of arm drop.

5. It is caused by poor sealing of the distribution pump, also known as "oil unloading". At this time, the sealing ring of the distribution pump needs to be replaced.

6. Poor contact of the hydraulic pump proportional solenoid valve connector will also cause the phenomenon of arm drop of the large and small arms.

7. Severe arm drop (the oil temperature is about 45°C, and the bucket teeth drop by more than 95mm in 5 minutes), most likely caused by the main valve being stuck.

Excavator dropped arm processing method:

1. Check the operating environment temperature of the excavator, whether there is improper selection of hydraulic oil type, and whether inferior hydraulic oil is used.

2. In the event of an arm drop failure, you can first reduce the pressure of the boom and carefully observe whether the boom falls quickly.

3. Check whether the hydraulic cylinder and the oil seal of the oil cylinder are faulty. If the oil seal is not well sealed, oil will leak. The oil seal should be replaced in time.

4. After replacing the oil seal, if the arm is still missing, check the distribution valve and the oil return safety valve of the arm.

5. Check whether the working pressure and pilot pressure of the main hydraulic pump of the excavator meet the requirements.