At the heart of every heavy construction machine lies a powerful hydraulic system. These systems are responsible for transferring power and force to execute a wide array of tasks with precision and brute strength.

The nature of hydraulic systems allow for a seamless transmission of force, reduced mechanical wear and the ability to amplify power instantaneously. It is this hydraulic muscle that’s revolutionized the landscape of heavy construction, making it a fundamental aspect of modern heavy equipment machinery.

As the complexity of heavy equipment continues to advance, hydraulic systems evolve in parallel, embracing new technologies to meet the demands of a rapidly changing industry. Understanding these hydraulic systems and effectively maintaining them is a responsibility no fleet manager or heavy equipment operator can afford to overlook.

In this guide, we’ll delve into the inner workings of hydraulic systems found in heavy construction equipment. By understanding the function of hydraulic systems and implementing preventive maintenance practices, fleet managers can ensure optimal performance, an increased lifespan and enhanced safety for their fleets.

Benefits of Hydraulic System Maintenance

Like all intricate systems, hydraulic systems require attentive care to ensure their reliability and longevity. Implementing an effective preventive maintenance plan for your machine’s hydraulic system is key to keeping your fleet on the job and minimizing downtime.

A neglected hydraulic system will result in severe consequences for the health of your machine. Leaking seals, contaminated hydraulic fluid or worn-out components can cause a loss of power, decreased machine control and total system failure.

The cost of repairs and downtime resulting from such negligence can dwarf the expenses of routine maintenance, making a preventive maintenance plan a wise investment.

When your machine’s hydraulic system goes unmaintained, it may degrade and start to break down. Here are the most common signs that your hydraulic system is failing:

1. Abnormal Noises: Unusual knocking, banging or whining sounds during machine operation may indicate air in the hydraulic system, cavitation or damaged components. These noises should never be ignored and warrant immediate investigation.
2. Leaks and Fluid Contamination: Any visible leaks or signs of fluid contamination around hydraulic hoses, fittings or cylinders demand prompt attention. Leaking hydraulic fluid not only depletes the system's performance but can also lead to environmental hazards and potential safety risks.
3. Slow or Erratic Movements: Delayed or unpredictable responses to control inputs could signal issues with the hydraulic pump, valves or actuators. This not only hinders productivity but also poses safety concerns.

Key Areas of Hydraulic System Maintenance

Daily Maintenance Tasks for Heavy Equipment Hydraulic Systems

There are several steps operators can take each day to ensure that their machine’s hydraulic system is working properly. Here are some critical daily tasks for maintaining your machine’s hydraulic system:

1. Check Hydraulic Fluid Levels: Inspect the hydraulic fluid levels using the machine's sight glass or dipstick. Ensure the fluid is at the appropriate level and top up as needed with the recommended hydraulic fluid.
2. Inspect for Leaks: Thoroughly examine all hydraulic hoses, fittings and connectors for any signs of leaks. Address and repair any leaks immediately to prevent fluid loss and system damage.
3. Check Hydraulic Reservoir Breather: Ensure that the breather on the hydraulic reservoir is clean and functioning correctly. A clogged breather can cause pressure issues and lead to contamination.
4. Inspect Hydraulic Cylinders: Examine the hydraulic cylinders for any signs of damage, such as dents, scoring or leaks. Address any issues promptly to prevent further damage and maintain proper functionality.
5. Inspect Hydraulic Hoses for Wear: Regularly inspect hydraulic hoses for signs of wear, abrasion or damage. Replace any worn or damaged hoses to prevent leaks and ensure safety.

Maintaining the Hydraulic Fluid

Your machine’s hydraulic fluid, or oil, plays a vital role in the efficiency and longevity of the hydraulic system. Keeping this critical fluid clean is not only a matter of routine maintenance, it is the key to unlocking optimal performance in your machine.

One of the biggest threats to your machine’s hydraulic fluid is contamination. As you operate your machine, debris and other contaminants may make their way into the hydraulic system through small clearances around cylinders or hose fittings.

Once inside the hydraulic system, abrasive contaminants such as silica may begin to disrupt the function of the system and degrade vital components like seals and gaskets. Hence, it is extremely important to maintain your machine’s hydraulic fluid and filters.

Signs that your machine’s hydraulic fluid has become contaminated include:

1. Cloudy Appearance: Clean hydraulic fluid should be transparent and free from cloudiness or haziness.
2. Discoloration: Contaminated fluid may appear darker than usual or have an unusual color.
3. Foaming: Foaming in the hydraulic fluid indicates the presence of air, which can reduce the system's performance.
4. Unusual Odors: Foul or burnt odors can be an indication of degraded or contaminated hydraulic oil.
5. Increased Heat: Contaminated fluid can cause increased friction and heat in the system, leading to overheating issues.

To minimize contamination of your machine’s hydraulic fluid, there are a few important steps you can take:

1. Perform frequent visual inspections of the hydraulic system
2. Keep the work area clean and free from dust
3. Replace hydraulic filters according to the intervals in the machine’s service manual
4. Inspect seals and o-rings frequently, replace as needed
5. Store hydraulic fluid properly and in a clean location
6. Filter new hydraulic fluid before adding it to your machine
7. Use the recommended hydraulic fluid for your machine and conditions
8. Address leaks promptly
9. Perform regular fluid analysis to check for contamination

In addition to these maintenance practices, you may occasionally need to flush or bleed the hydraulic system. Flushing involves removing the old hydraulic fluid and replacing it with new fluid, while bleeding involves removing air from the system.

Final Thoughts

Ignoring initial symptoms or neglecting routine hydraulic system maintenance may seem like a cost-saving measure in the short term, but the consequences can be far-reaching and expensive down the road.

A neglected hydraulic system is a ticking time bomb that can lead to significant equipment downtime, costly repairs and, in the worst-case scenario, complete machine failure during critical operations.

By following maintenance best practices, operators and fleet managers can extend the life of their machines’ hydraulic systems and prevent costly breakdowns.

The MechLink Shop is a convenient place to solve all your hydraulic system needs. Our online parts catalog offers a wide range of OEM and aftermarket hydraulic system components, like filters, sealing components and more. Can’t find the part you’re looking for? Contact one of our parts experts and get personalized assistance.