液压缸一旦出现压力失常，液压系统的执行元件将很难执行正常的工作循环，可能出现始终处于原始位置不工作，动作速度显著降低，动作时相关的控制阀组常发出刺耳的噪声，导致机器处于非正常状态，影响整机的使用性能。
1、 Reasons related to hydraulic pumps and motors
1.液压泵、马达使用时间过长，内部磨损严重，泄漏较大，容积效率低导致液压泵输出流量不够，系统压力偏低。
2.发动机转速过低，效率不足，导致系统流量不足，液压系统压力偏低。
3. The directional control device of the hydraulic pump is in the wrong position or assembled incorrectly, the pump does not work, and the system has no pressure.
二、液压控制阀的原因
1.工作过程中，若发现压力上不去下不来的情况，很可能是换向阀失灵，导致系统持续卸荷或持续高压。
2. Blockage of the damping hole of the overflow valve, burrs on the main valve core, and dirt between the valve core and the valve hole and gap may cause the main valve core to get stuck in the fully open position. The hydraulic oil output by the hydraulic pump directly returns to the oil tank through the overflow valve, and the pressure oil circuit is short circuited with the return oil circuit, resulting in no pressure in the system; If burrs or dirt jam the main valve core in the closed position, there may be a phenomenon where the system pressure remains high and cannot be reduced; When the valve core of the overflow valve or directional valve is stuck, the valve core will not move flexibly, and the executing components will have intermittent movements. When detecting the system pressure, it will be manifested as unstable pressure.
3.有单向阀的系统，若单向阀的方向装反，也可能导致系统压力上不去。
4.系统内外泄漏，例如阀芯与阀体孔之间泄漏严重，也会导致系统压力上不去。
三、其他方面的原因
1.液压油箱油位过低、吸油管太细、吸油过滤器被杂质污物堵塞会导致液压泵吸油阻力过大，导致系统流量不足，压力偏低。
2.另外，回油管在液面上，吸油管密封不好漏气等容易造成液压系统中混入空气，导致系统压力不稳定。
GEO-CANARY-86EA1707