Nowadays, the mining loader is an indispensable working tool in various engineering projects, but it often encounters many faults when in use. Once there is a fault, it will give customers a headache. The following are the reasons for the automatic falling of the boom of the mining loader:

1、动臂操作滑阀的操纵机构调整不当，使动臂滑阀未能完全处于中位，应检查操纵机构是否调整在中。

1. The control mechanism of the boom operating spool valve is not adjusted properly, so that the boom spool valve cannot be fully in the middle position. Check whether the control mechanism is adjusted in the middle position.

2、动臂油缸活塞密封圈损坏或油缸缸筒损坏，造成油缸内泄严重，应更换密封件或更换动臂油缸。

2. If the piston seal ring of boom cylinder is damaged or the cylinder barrel is damaged, resulting in serious internal leakage of the cylinder, replace the seal or replace the boom cylinder.

3、分配阀动臂滑阀阀杆磨损过度，密封不严，应更换分配阀。

3. The valve rod of the boom slide valve of the distribution valve is excessively worn and the seal is not tight. The distribution valve should be replaced.

4、分配阀上的阀损坏，引起内泄。

4. The safety valve on the distribution valve is damaged, causing internal leakage.

以上是对小型装载机大臂下落原因的分析，希望对广大客户有所帮助，还有就是判断是分配阀还是油缸的原因引起动臂自动下降的方法为：将动臂举高位置，将动臂阀杆致于中位，听动臂油缸处有无响声，如果有嘭、嘭的响声，则为分配阀有故障，如果没有响声，则可能是油缸的问题，应拆检油缸。

The above is the analysis of the reasons for the fall of the boom of the small loader. I hope it can be helpful to our customers. Also, the method to judge whether it is the distribution valve or the oil cylinder that causes the boom to drop automatically is: lift the boom to the high position, turn the boom valve rod to the middle position, and listen to whether there is a sound at the boom oil cylinder. If there is a bang and bang, the distribution valve is faulty. If there is no sound, It may be a problem with the oil cylinder, and the oil cylinder should be disassembled and inspected.