Hitachi EX200LC-2 Erratic Hydraulic Controls: Diagnosis and Solutions

[MikePhua]

Introduction to the Hitachi EX200LC-2
The Hitachi EX200LC-2 is a mid-size hydraulic excavator widely used in construction, demolition, and landscaping projects. Known for its durability, efficiency, and powerful hydraulic systems, the EX200LC-2 has earned a reputation as a reliable workhorse on demanding job sites. However, like all complex machines, the EX200LC-2 can encounter issues, particularly with its hydraulic controls. One common problem reported by operators is erratic hydraulic control behavior, which can significantly impact machine performance and productivity.
Hydraulic controls are integral to the smooth operation of the excavator, allowing the operator to control movements such as the boom, bucket, and swing. When these controls become erratic, it can be frustrating and potentially dangerous, as it affects the operator’s ability to move materials or perform tasks with precision. Understanding the potential causes of erratic hydraulic behavior and knowing how to diagnose and resolve these issues is crucial for maintaining the excavator’s performance.
The Hydraulic System in the Hitachi EX200LC-2
Before diving into troubleshooting, it’s important to understand how the hydraulic system in the Hitachi EX200LC-2 works. The hydraulic system is responsible for providing the force needed to power the various functions of the excavator, including lifting, digging, and swinging. It operates using pressurized fluid that is pumped through various lines and valves to actuators that move the machine's components.
The key components of the hydraulic system include:

1. Hydraulic Pump: The pump generates the hydraulic pressure needed to power the system.
   
2. Control Valves: These valves direct the flow of hydraulic fluid to different parts of the machine, such as the boom, arm, bucket, and swing.
   
3. Hydraulic Cylinders: These are used to convert hydraulic pressure into mechanical force to move the machine’s various components.
   
4. Hydraulic Fluid: The fluid serves as the medium through which pressure is transmitted to the cylinders and actuators.
   
5. Filters: Filters are essential for maintaining clean hydraulic fluid, preventing debris from clogging the system and causing damage to the components.
   

A malfunction in any of these components can lead to erratic hydraulic controls, causing slow or uneven movements, jerking motions, or a complete loss of control over specific functions.
Common Causes of Erratic Hydraulic Controls
There are several potential causes for erratic hydraulic controls in the Hitachi EX200LC-2. Understanding these causes is the first step in troubleshooting and resolving the issue.

1. Low Hydraulic Fluid Levels: One of the most common causes of erratic hydraulic behavior is low hydraulic fluid levels. Hydraulic systems rely on adequate fluid levels to maintain pressure and allow smooth operation. If the fluid level drops below the recommended range, the pump may not generate enough pressure to move the hydraulic cylinders properly, leading to jerky or slow movements.
   
2. Contaminated Hydraulic Fluid: Over time, hydraulic fluid can become contaminated with dirt, metal shavings, or other debris. This contamination can cause blockages in the hydraulic lines and valves, leading to erratic operation. Contaminated fluid can also cause excessive wear on the system's components, leading to more severe damage.
   
3. Worn Hydraulic Pump: A worn or damaged hydraulic pump may not be able to generate sufficient pressure, resulting in poor or inconsistent hydraulic control. Symptoms of a failing pump can include a noticeable decrease in power or sudden loss of hydraulic function.
   
4. Faulty Control Valves: The control valves direct the flow of hydraulic fluid to the appropriate cylinders and actuators. If the control valves are malfunctioning, they may send fluid to the wrong locations or restrict fluid flow, causing erratic movements. Sticking or clogged valves are common culprits for hydraulic issues.
   
5. Air in the Hydraulic System: Air trapped in the hydraulic lines can lead to erratic movements or a lack of power. When air enters the system, it compresses under pressure, causing a loss of efficiency and inconsistent control of hydraulic functions.
   
6. Leaking Hydraulic Hoses or Fittings: Leaks in the hydraulic system can cause a drop in pressure, leading to sluggish or erratic movements. Inspecting the hoses, fittings, and seals for signs of wear or leaks is an essential part of diagnosing hydraulic problems.
   
7. Electrical Issues or Faulty Sensors: The EX200LC-2’s hydraulic system is also governed by electrical sensors and control units that monitor and adjust the system's performance. If there is an electrical issue, such as a faulty sensor or a malfunctioning control unit, it can lead to erratic hydraulic behavior, as the system may not be receiving the correct data to regulate pressure and fluid flow properly.
   

Troubleshooting Hydraulic Control Issues in the Hitachi EX200LC-2
To diagnose the cause of erratic hydraulic controls in the Hitachi EX200LC-2, follow these steps:

1. Check Hydraulic Fluid Levels: Start by checking the hydraulic fluid levels. If the fluid is low, top it up with the manufacturer-recommended fluid. Low fluid levels can result from leaks, so it’s important to inspect for signs of leakage as well.
   
2. Inspect for Contaminated Fluid: Examine the fluid for any signs of contamination, such as dirt, water, or metal particles. If the fluid appears dirty or contaminated, perform a hydraulic fluid change and replace the filters. Contaminated fluid can cause blockages and wear down hydraulic components.
   
3. Test the Hydraulic Pump: Check the hydraulic pump to ensure it is generating the proper pressure. A pressure test can help identify if the pump is working efficiently. If the pump is found to be faulty, it may need to be repaired or replaced.
   
4. Inspect Control Valves: Inspect the control valves for any signs of damage or sticking. Valves can become clogged with dirt or debris, causing erratic control. If necessary, clean or replace the valves to restore smooth hydraulic operation.
   
5. Bleed the Hydraulic System: If air is suspected to be trapped in the hydraulic system, bleed the system to remove any trapped air. Follow the manufacturer’s guidelines for bleeding the system to avoid damage and ensure proper fluid flow.
   
6. Check for Leaks: Inspect all hydraulic hoses, fittings, and seals for leaks. Even small leaks can cause a significant drop in pressure, leading to hydraulic issues. Repair or replace any faulty hoses or fittings as necessary.
   
7. Test Electrical Sensors and Controls: Check the electrical sensors and control units to ensure they are functioning properly. Faulty sensors or control units can send incorrect data to the hydraulic system, leading to erratic behavior. Use a diagnostic tool to read any fault codes or test the sensors.
   

Preventive Maintenance Tips for the Hydraulic System
To avoid future hydraulic issues and ensure the long-term reliability of your Hitachi EX200LC-2, follow these preventive maintenance practices:

1. Regular Fluid Checks: Regularly check the hydraulic fluid levels and condition. Replace the fluid and filters according to the manufacturer’s recommended schedule to keep the system running smoothly.
   
2. Inspect Hydraulic Lines: Periodically inspect hydraulic hoses and fittings for wear, leaks, or damage. Replace any damaged hoses or seals before they cause a significant drop in performance.
   
3. Clean or Replace Filters: Ensure the hydraulic filters are clean and free of debris. Replace filters as needed to prevent contamination from affecting the hydraulic system.
   
4. Lubricate Moving Parts: Proper lubrication of moving parts, such as control valves and cylinders, can help prevent wear and ensure smooth operation. Regular lubrication also reduces friction and prolongs the lifespan of the components.
   
5. Monitor System Performance: Keep an eye on the performance of the hydraulic system. If you notice any changes in how the excavator operates, such as a decrease in power or responsiveness, investigate the cause before it leads to a larger issue.
   

Conclusion
Erratic hydraulic controls in the Hitachi EX200LC-2 can be caused by a range of issues, from low fluid levels to malfunctioning pumps or valves. By systematically diagnosing the problem and addressing the root cause, operators can restore the hydraulic system to full functionality and prevent further issues. Regular maintenance, including fluid checks, filter changes, and inspection of hydraulic components, can help prevent these problems from occurring in the future. Understanding the intricacies of the hydraulic system and performing routine upkeep will ensure that the EX200LC-2 continues to perform efficiently and reliably on the job site.