（1）The way water enters the hydraulic system

There are roughly three ways that water enters the hydraulic system:

①Mechanical failure, such as poor sealing, cooling coil leakage so that water into the oil.

② in the hot and humid climate, the oil tank breathing and brought in.

③Working environment humidity, rain, snow, melting ice produced by water contamination

（2） The Hazards of Water in Hydraulic Systems

Water can react with hydraulic oil, forming acids, colloids, and sludge. Water can also cause the precipitation of additives from the oil. The primary impact of water is a reduction in lubricity. Even trace amounts of water dissolved in hydraulic oil can accelerate the wear of high-stress components. Research on fatigue life of mineral oil rolling bearings with water content (100-400) × 10-6 shows a 30%-70% reduction in bearing life. Water can cause sticking of control valves, cavitation damage at the pump inlet or other low-pressure areas, and corrosion or rusting of metal components.

（3） Solutions

Strengthen the monitoring of water content in oil. For hydraulic equipment used outdoors, it is best to use weatherproof tents and strengthen system sealing measures to prevent water from entering. A dryer is installed in the breathing hole of the fuel tank, and a "super adsorption type" drying filter can be installed on the system if conditions permit.