What is excavator arm drop?

Excavator arm drop is also referred to as boom, self fall, drop pump, and so on. Simply put, arm drop is actually a manifestation of the weakness of the excavator boom. When the boom is lifted, the upper or lower arm will automatically fall without the need for joystick control.
When an excavator experiences arm failure, different manifestations can also occur. The fault symptoms can be roughly divided into arm failure of the upper arm, arm failure of the lower arm, arm failure of the middle arm, arm failure of a cold or hot car, and so on.

7 common causes of arm failure

1. Arm drop caused by hydraulic oil malfunction. If the arm falls off when the car is cold or hot, it is very likely that there is a problem with the hydraulic oil.

2. The hydraulic cylinder of the excavator malfunctions, especially the oil seal of the cylinder is damaged or aged, causing internal leakage of the oil seal.

 3. Blockage of the distribution valve hole, wear of the valve core, excessive clearance between the valve core, and wear and damage of the main safety valve of the distribution valve, resulting in the suspension of the large and small arms.

4.When the oil seal of the safety overflow valve of the large and small arms is damaged, it can cause certain leakage and also lead to arm drop phenomenon. 

5. If it is caused by poor sealing of the distribution pump, also known as "oil unloading", the sealing ring of the distribution pump needs to be replaced.

6. Poor contact of the proportional solenoid valve joint of the hydraulic pump can also cause the phenomenon of large and small arms falling off.

 7. Severe arm falling (oil temperature of about 45 ℃, tooth drop of more than 95mm in 5 minutes) is most likely caused by the main valve being stuck.

What should I do if an excavator loses its arm?

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

2.When an arm failure occurs, you can first reduce the pressure on the boom and carefully observe whether the boom falls quickly.

3. Check if there are any faults in the hydraulic cylinder and cylinder oil seal. Poor sealing of the oil seal can cause oil leakage, so it is necessary to replace the oil seal in a timely manner.

4.After replacing the oil seal, if the arm still falls off, check the distribution valve and the boom return oil safety valve.

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