Water in Hydraulics: Causes, Impact, and Solutions for Heavy Equipment

[MikePhua]

Water contamination in hydraulic systems is a common issue that can lead to a range of operational problems in heavy machinery. The presence of water in hydraulic fluids can result in reduced efficiency, corrosion, and even total system failure. This article will discuss the causes of water contamination in hydraulic systems, its effects on performance, and the steps that can be taken to resolve and prevent this issue.
Understanding Hydraulic Systems and Their Sensitivity to Water
Hydraulic systems are essential to the operation of many heavy machines, including excavators, bulldozers, and cranes. These systems rely on hydraulic fluid, which transfers power through the system to operate various components such as lifts, arms, and tracks.
Hydraulic fluid is designed to lubricate moving parts, transmit power, and dissipate heat. The introduction of water into the hydraulic fluid disrupts these processes and can lead to a wide variety of problems. As hydraulic systems are typically pressurized and require smooth and consistent flow of fluid, even small amounts of water can have detrimental effects.
Common Causes of Water in Hydraulic Systems

1. Condensation
   One of the most common causes of water in hydraulic systems is condensation. When equipment is exposed to varying temperatures, moisture can form inside the hydraulic reservoir. This is especially common in cold climates where machinery is stored outside or where there are significant fluctuations in temperature. As the hydraulic fluid cools, it can trap moisture in the system, leading to the gradual buildup of water.
   
2. Rain or Flooding
   In some cases, water may enter the hydraulic system directly from external sources such as rain or flooding. This often occurs when seals, gaskets, or covers on the hydraulic components are compromised, allowing water to seep into the fluid reservoir. If the equipment is used in areas prone to heavy rainfall or flooding, there’s an increased risk of water contamination.
   
3. Faulty Seals and Gaskets
   The seals and gaskets in a hydraulic system are designed to prevent contaminants, including water, from entering. Over time, these seals can degrade or become damaged, allowing water to enter the hydraulic fluid. Inadequate maintenance or the use of worn-out components can lead to leaks that allow water to mix with the hydraulic fluid.
   
4. Hydraulic Fluid Breather Contamination
   The breather valve of a hydraulic system is designed to allow air to enter and exit the system as it operates. However, if the breather valve is exposed to rain, humidity, or high levels of moisture, water can enter through the breather and mix with the hydraulic fluid. This is particularly problematic if the breather is not adequately sealed or if the system operates in an environment with high moisture content.
   
5. Improper Fluid Handling or Maintenance
   During fluid changes, the improper handling of hydraulic fluid can introduce water into the system. For example, if the fluid is stored improperly or exposed to moisture during transfer, it may become contaminated before it even enters the hydraulic system.
   

Impact of Water on Hydraulic Systems
Water contamination in hydraulic systems can lead to several detrimental effects:

1. Corrosion of Components
   One of the most significant risks posed by water in hydraulic systems is corrosion. The presence of water can cause rust and degradation of metal components, including the pumps, valves, and cylinders. Over time, this corrosion can lead to expensive repairs and replacements.
   
2. Decreased Lubrication and Efficiency
   Hydraulic fluids are formulated to provide lubrication to moving parts, but water disrupts this process. The presence of water causes the fluid to lose its lubricating properties, which increases friction and wear on components. As a result, the machine may experience reduced performance and efficiency, causing overheating and a shorter lifespan for critical components.
   
3. Reduced Heat Dissipation
   Water in hydraulic systems interferes with the fluid’s ability to dissipate heat. Heat is generated during the operation of hydraulic components, and the fluid is responsible for carrying this heat away from sensitive areas. When water is present, the hydraulic fluid’s heat-carrying capacity is diminished, which can lead to overheating and potential system failure.
   
4. Foaming and Cavitation
   Water in hydraulic fluid can cause foaming, which negatively impacts the system's performance. Foaming occurs when air becomes trapped in the fluid, causing bubbles to form. This disrupts the smooth flow of the fluid and can lead to cavitation, a phenomenon where air bubbles implode within the system. Cavitation can cause significant damage to components such as pumps and valves.
   
5. Increased Wear on Seals and Components
   The presence of water can cause the breakdown of seals, gaskets, and O-rings in the hydraulic system. These components are designed to provide a tight seal and prevent leakage, but the presence of water can degrade them, leading to further contamination and performance issues.
   

How to Detect Water in Hydraulic Systems

1. Visual Inspection
   The first step in detecting water contamination is a visual inspection of the hydraulic fluid. Hydraulic fluid that contains water may appear cloudy or milky in color, and may separate into different layers if left standing. A clear indication of water contamination is the presence of small droplets or an unusual color of the fluid.
   
2. Water Content Test
   A water content test, such as the crackle test, can be used to confirm the presence of water in hydraulic fluid. In this test, a small sample of the hydraulic fluid is heated, and if the fluid crackles or produces steam, it indicates the presence of water. Another method is to use a water-in-oil sensor, which measures the percentage of water in the fluid.
   
3. Performance Issues
   If the hydraulic system experiences a loss of power, irregular movement, overheating, or unusual noise, it may be a sign that water has contaminated the hydraulic fluid. These performance issues can often serve as a warning that water is present in the system.
   

Steps to Remove Water from Hydraulic Systems

1. Draining and Flushing
   If water contamination is detected, the first step is to drain the contaminated fluid from the system. Once the old fluid is removed, the system should be thoroughly flushed to remove any residual water and debris. It is essential to follow the manufacturer’s guidelines when performing this procedure to ensure that all contaminants are eliminated.
   
2. Replacing the Hydraulic Fluid
   After flushing, the hydraulic system should be filled with fresh, clean hydraulic fluid. Make sure to use the recommended type of fluid for your equipment to ensure optimal performance and protection.
   
3. Replacing Damaged Seals and Gaskets
   Check the seals, gaskets, and filters for signs of wear or damage. Replace any components that have been compromised to prevent further water entry into the system.
   
4. Using a Desiccant Breather
   To prevent moisture from entering the hydraulic system in the future, consider installing a desiccant breather. These breathers are designed to absorb moisture from the air, preventing condensation from forming inside the hydraulic reservoir.
   
5. Regular Maintenance
   Routine maintenance is crucial for preventing water contamination. Regularly check for signs of water in the fluid, inspect the breather, and maintain seals and gaskets to ensure that they remain intact and functioning properly.
   

Conclusion
Water in hydraulic systems is a serious issue that can lead to significant damage and performance issues in heavy machinery. Understanding the causes, impact, and solutions for water contamination is key to maintaining the longevity and efficiency of hydraulic systems. Regular inspections, proper fluid handling, and routine maintenance can help prevent water contamination and ensure that hydraulic systems continue to operate at peak performance. By addressing water contamination early and taking proactive measures, equipment owners can avoid costly repairs and downtime.