Hitachi EX60-2 Hydraulic Swing System: Troubleshooting and Solutions

[MikePhua]

The Hitachi EX60-2 is a popular model of mini-excavator that has been widely used in various industries for its impressive capabilities, compact size, and durability. However, like all machinery, it is not immune to issues, especially with critical components like the hydraulic swing system. In this article, we will explore the common issues related to the hydraulic swing of the EX60-2, provide a detailed troubleshooting guide, and discuss preventive measures to maintain the system in peak condition.
The Hitachi EX60-2 Excavator: A Quick Overview
The Hitachi EX60-2 is part of Hitachi's series of compact hydraulic excavators, built to provide high performance in tight spaces and on smaller construction sites. It features a powerful engine, excellent digging capability, and efficient hydraulics, making it ideal for urban construction, landscaping, and utility work.
Key Specifications:

• Operating Weight: Approximately 6,000 kg (13,200 lbs)
  
• Engine Power: 48 kW (64 hp)
  
• Max Digging Depth: 4,180 mm (13.7 feet)
  
• Swing Speed: 9.4 rpm
  
• Hydraulic Flow: 160 L/min (42.2 US gal/min)
  

The machine’s compact design and smooth operation make it a favorite for operators who need to navigate through narrow spaces, while its hydraulic system ensures powerful digging and swinging action for most tasks.
The Hydraulic Swing System: An Overview
The hydraulic swing system in the Hitachi EX60-2 excavator allows the machine’s upper structure to rotate on its undercarriage, providing operators with the flexibility to work in all directions. The swing mechanism is powered by hydraulic pumps, which supply oil under pressure to the swing motor. This motor drives a large gear or hydraulic motor that turns the upper structure.
Typical components of the hydraulic swing system include:

• Hydraulic Swing Motor: Powers the rotation of the machine’s upper structure.
  
• Swing Gear: Translates the power from the motor to the rotation of the upper structure.
  
• Swing Cylinder: Acts as a stabilizer and assists with the swinging movement.
  
• Hydraulic Pump: Delivers fluid to the swing motor at a high pressure.
  

Common Hydraulic Swing Issues in Hitachi EX60-2
Over time, operators may experience problems with the hydraulic swing system, ranging from slow or erratic movement to complete failure. Some common issues include:
1. Slow Swing Speed
A slow swing speed is one of the most common complaints about the hydraulic swing system in the EX60-2. This can make it difficult to complete tasks efficiently, especially when the operator needs to rotate the upper structure quickly to reposition the machine or avoid obstacles.
Common causes of slow swing speed include:

• Low Hydraulic Fluid: Insufficient fluid can result in low hydraulic pressure, leading to reduced swing speed.
  
• Clogged Filters: Dirty or clogged hydraulic filters can restrict fluid flow and reduce the overall performance of the swing system.
  
• Damaged Swing Motor: A malfunctioning swing motor can cause the swing speed to decrease. This may be due to worn-out seals or internal damage.
  
• Hydraulic Pump Issues: If the hydraulic pump is not generating the correct pressure, it can affect the swing system’s performance.
  

2. Erratic Swing Movement
Erratic or jerky movement during swinging can indicate an issue with the hydraulic system or a component failure. This issue can affect the precision of the operator’s movements, especially when working in confined spaces.
Common causes include:

• Air in the Hydraulic System: Air trapped in the hydraulic lines can cause jerky movements and inconsistent response. This can happen due to leaks in the system or improper fluid filling.
  
• Faulty Swing Motor Valve: The swing motor valve is responsible for controlling the flow of hydraulic oil to the swing motor. If the valve is damaged or malfunctioning, it can cause erratic movements.
  
• Worn Hydraulic Components: Worn or damaged components, such as seals or bearings in the swing motor, can lead to erratic performance.
  

3. Complete Loss of Swing Functionality
A total loss of swing functionality, where the machine’s upper structure will not rotate at all, is one of the most severe hydraulic swing issues. This can halt the machine’s ability to perform tasks effectively and may require immediate repair.
Potential causes include:

• Broken Hydraulic Line: If a hydraulic line is ruptured or cracked, the fluid may leak out, causing a complete loss of pressure in the system and preventing the swing motor from functioning.
  
• Failed Swing Motor: A total failure of the swing motor may result in an inability to rotate the upper structure. This is often due to internal mechanical damage or worn-out parts.
  
• Clogged or Dirty Filters: A severe clog in the hydraulic filters can restrict oil flow, cutting off supply to the swing motor and leading to a loss of function.
  
• Low Hydraulic Fluid: Inadequate fluid levels can reduce hydraulic pressure to the swing system, preventing it from operating.
  

Troubleshooting and Solutions
For operators experiencing any of the above issues, troubleshooting the hydraulic swing system requires a methodical approach. Here’s a step-by-step guide:
1. Check Hydraulic Fluid Levels
Start by checking the hydraulic fluid levels in the system. Low fluid levels can lead to low pressure, causing slow swing speed or a complete loss of swing function. If the fluid is low, top it off with the correct type of hydraulic fluid, and check for any visible leaks.
2. Inspect Filters and Hoses
Dirty or clogged filters can impede fluid flow and cause performance issues. Inspect the hydraulic filters and replace them if necessary. Similarly, check all hydraulic hoses for leaks or damage, as they can affect the pressure within the system.
3. Check for Air in the System
Air in the hydraulic lines can cause erratic swing movements. To remove air, it may be necessary to bleed the system by loosening certain connections, allowing trapped air to escape.
4. Examine the Swing Motor and Gear
If there is still no improvement after checking fluid levels and filters, inspect the swing motor and swing gear for any visible signs of wear or damage. A damaged swing motor may require replacement or overhaul, while issues with the swing gear may require adjustment or repair.
5. Test the Hydraulic Pump
If all other components appear to be functioning properly, the issue may lie with the hydraulic pump. Test the pump for correct output pressure and flow, as a malfunctioning pump can drastically affect the swing system’s performance.
Preventive Maintenance Tips
Regular preventive maintenance can help ensure that the hydraulic swing system on your Hitachi EX60-2 operates smoothly. Here are a few essential tips to keep in mind:

• Change Hydraulic Fluid Regularly: Change the hydraulic fluid according to the manufacturer's recommendations to prevent contamination and ensure smooth operation.
  
• Inspect Hydraulic Components: Regularly inspect the swing motor, swing gear, and other components for wear and tear. Replace parts before they fail to avoid costly repairs.
  
• Clean Filters Frequently: Clean or replace hydraulic filters regularly to maintain proper fluid flow and prevent system blockages.
  
• Monitor Fluid Temperature: Overheating hydraulic fluid can cause performance issues and damage components. Keep an eye on the fluid temperature, especially during heavy-duty operations.
  
• Use High-Quality Hydraulic Fluid: Always use the recommended type and grade of hydraulic fluid to ensure the system operates efficiently.
  

Conclusion
The hydraulic swing system is a critical component of the Hitachi EX60-2 mini-excavator. Proper maintenance, timely troubleshooting, and a keen eye for potential issues can ensure that the swing system remains reliable and functional. By addressing common problems like slow swing speed, erratic movements, and loss of swing functionality early on, operators can extend the life of their equipment and reduce downtime.
Remember, regular inspections, proper fluid management, and adhering to the manufacturer’s maintenance schedule are key to keeping the Hitachi EX60-2 running smoothly and efficiently for years to come.