The slow solution of the excavator arm

Published by HuiTong 2023-04-04

In winter, the temperature drops sharply, and most of the excavators in the north are basically in a state of shutdown except for the mines, while the south can still operate, but the sudden drop in temperature will still have a certain impact on the performance of the excavators, such as excavators. The right arm - the excavator arm.


We often encounter the situation that the excavator suddenly becomes very slow in the movement of the excavator arm during the operation, which is a typical failure caused by low temperature. And how do we deal with this situation?


excavator arm


Fault phenomenon

The most obvious phenomenon of this fault is that all the movements of the excavator are normal, and there is no abnormality in terms of speed or strength. Only when the forearm is retracted, it becomes very, very slow, but it is normal to release the forearm.


From this phenomenon, it can basically be determined that the fault point is on the forearm of the hydraulic system, and which component it is, we still need to continue to check.


excavator arm



Step 1: We first measure the pilot pressure of the machine with a pressure gauge. If the pressure value is about 35Kg/cm2, the control oil circuit problem from the operating handle to the main control valve forearm recovery valve stem can be basically eliminated.


The second step: We start to check the forearm holding valve, which is installed on the pilot oil circuit of the forearm recovery valve stem on the main control valve. Its main function is that when the forearm joystick is in the neutral position, the holding valve can prevent Under the action of its own weight, the forearm oil cylinder returns to the fuel tank through the main spool of the forearm, which means that it prevents the forearm from falling naturally.


Step 3: If we check the forearm holding valve and find that the poppet valve needle is broken, other parts are intact, and the forearm valve stem is also normal without any signs of wear, then it can be determined that the fault is caused by the breakage of the valve needle.


excavator arm


Cause of issue

So what is the cause of the failure? The main reason is that the optimal working temperature of hydraulic oil is around 50 degrees. In winter, the weather is cold and the temperature drops. If the hydraulic oil is too cold, it will become viscous and the lubricity will decrease, which will cause the hydraulic components to wear and even break. 


After the valve needle of the excavator arm holding valve is broken, the locking valve cannot be fully opened, so it will cause the excavator arm to recover slowly due to insufficient hydraulic oil flow when the forearm is recovered.



For the above fault phenomenon, the solution is actually very simple. After it is determined that the spool of the excavator arm holding valve is damaged, we only need to replace the new forearm holding valve, so that the fault is completely solved.


However, in order to maintain the good working performance of the hydraulic system in winter, whether in the south or the north, the hydraulic system should be replaced with special hydraulic oil in winter, which can greatly reduce the wear of hydraulic components and prevent the failure from happening again.