When a hydraulic system fails, it is a challenge to find the root cause of the problem. Any component in the hydraulic system may be the source of the failure, and human operating errors and improper maintenance practices can also cause hydraulic system failures. If a hydraulic system fails, we need to understand the cause, locate the fault and solve it to ensure that the system can operate smoothly.

1. Failures caused by air and oil contamination

(1) Failures caused by air entering the hydraulic system

When air enters the hydraulic system, it may cause cavitation. When cavitation occurs, air bubbles in the high-speed fluid burst, generating local high temperature and high pressure, causing damage to the surface of the hydraulic components, especially the surface wear of the pump and valve. It will also cause obvious noise when the hydraulic system is running, especially in the pump and actuator. The air in the system will affect the flow and pressure changes of the hydraulic oil and produce the sound of bubble bursting. The presence of air will reduce the rigidity of the hydraulic system, causing the actuator to respond more slowly, and even cause the hydraulic cylinder to move unsteadily or inaccurately.

(2) Failures caused by oil contamination

Contaminants in hydraulic oil, such as particles and metal debris, can easily enter the interior of hydraulic components, causing wear on the surface of components, especially key components such as hydraulic pumps, valves and cylinders. Contaminants may cause blockage of hydraulic valves or oil circuits, affecting the normal operation of the system or even causing system failure. Chemical substances or particles in them may corrode or wear seals in the hydraulic system, causing leakage, pressure drop, and affecting system performance. Moisture, oxides and other contaminants can cause the hydraulic oil to deteriorate, changing its viscosity, lubricity and corrosion resistance, thereby affecting the efficiency and life of the hydraulic system.

2. Failure caused by temperature

(1) Failures caused by high temperature

Under high temperature, hydraulic oil will accelerate oxidation and decomposition, resulting in decreased viscosity and weakened lubrication performance, which will increase component wear. Degraded oil may form sediments, block pipes and filters, and cause unstable system pressure, reduced control accuracy of actuators, slower response speed or inaccurate action. High temperature can easily increase the number of bubbles in hydraulic oil, leading to cavitation problems in the hydraulic system, noise and component damage.

(2) Failures caused by low temperatures

At low temperatures, the viscosity of hydraulic oil increases and its fluidity deteriorates, resulting in difficulty in starting the hydraulic system, slow response speed, and inflexible movement of actuators. Hydraulic oil with too high viscosity cannot provide effective lubrication at low temperatures, resulting in increased wear of components such as hydraulic pumps, valves, and cylinders. It also increases the pressure loss of the system and the workload of the pump, which may cause excessive pressure inside the system, damage components, or cause the safety valve to operate frequently. The brittleness of metal components increases at low temperatures, especially hydraulic cylinders and connectors, which may crack or be damaged under load and low temperature conditions.

3. Failures caused by operational errors

(1) Failures caused by improper component installation and incompatibility:

① Failures caused by incorrect component installation

The incorrect installation position, angle or direction of key components such as hydraulic pumps, valves, and hoses may cause the system to fail to establish correct fluid flow and pressure.

② Failures caused by component incompatibility

The use of parts that do not meet system requirements or poor compatibility between parts of different brands may cause abnormal operation of the hydraulic system or direct damage to the system. For example, the use of mismatched hydraulic oil or seals may accelerate system wear and leakage.

(2) Failures caused by improper operation:

① Overload operation

Operating the hydraulic system under conditions that exceed the equipment design load will accelerate component wear, resulting in equipment performance degradation or hydraulic pump damage.

② Incorrect operation sequence

If the operator does not start and stop the system according to the correct steps, it may cause sudden pressure fluctuations in the system, affecting system stability and even causing damage to the hydraulic cylinder or pump.

③ Lack of training or lack of experience

The operator does not understand the working principle of the system or the troubleshooting method and may aggravate the fault due to wrong judgment.

(3) Failures caused by improper maintenance:

Hydraulic systems require regular inspection and maintenance to ensure efficient and stable operation. Improper maintenance often causes failures in hydraulic systems. Hydraulic systems require regular inspection, lubrication, and cleaning. Neglecting these tasks may cause moving parts to get stuck, friction to increase, or even seal failure of the hydraulic cylinder. Failure to regularly check important parameters such as pressure, temperature, and oil level may turn a small problem into a major failure. If the hydraulic oil is not replaced on time or the filter fails, contaminants will enter the hydraulic circuit, wear the pump and valve parts, and reduce the life and performance of the system.