What Does EX120 Mean in Hitachi EX120 Excavator

[MikePhua]

The Naming Logic Behind Hitachi’s EX Series
Hitachi’s EX-series excavators follow a structured naming convention that reflects machine class, design lineage, and operational capacity. In the case of the EX120, the “EX” prefix stands for “Excavator,” a designation used across Hitachi’s hydraulic crawler lineup. The number “120” refers to the machine’s nominal class size—roughly corresponding to a 12-ton operating weight. This numeric system allows operators and fleet managers to quickly identify the machine’s scale and intended application.
Hitachi began using the EX prefix in the late 1980s as part of its global branding strategy. Earlier models like the UH-series were phased out in favor of the EX line, which introduced improved hydraulics, cab ergonomics, and structural durability. The EX120 was one of the most successful mid-size models in this transition, bridging compact maneuverability with serious digging power.
Terminology Notes

• EX: Excavator series designation used by Hitachi for hydraulic crawler models.
  
• Operating Weight: The total weight of the machine including fuel, fluids, and standard attachments.
  
• Class Size: A general category based on weight and bucket capacity, used to group excavators for comparison.
  
• Hydraulic System: The network of pumps, valves, and cylinders that powers the boom, arm, bucket, and travel motors.
  

Technical Profile of the EX120
The Hitachi EX120 was manufactured between 1988 and 1990 and quickly became a staple on construction sites worldwide. Key specifications include:

• Operating weight: Approximately 11.8 metric tons
  
• Engine: 4-cylinder diesel, typically rated around 90–100 hp
  
• Bucket capacity: 0.5–0.6 cubic meters
  
• Digging depth: Over 6 meters
  
• Track width: 600 mm standard
  
• Boom reach: Up to 8.5 meters horizontal
  

Its compact frame and powerful hydraulics made it ideal for trenching, foundation work, and utility installation. A contractor in Alberta used an EX120 for pipeline trenching in frozen ground, noting that its breakout force and fuel efficiency outperformed newer machines in similar conditions.
Design Evolution and Market Impact
The EX120 was part of Hitachi’s push to standardize excavator design across international markets. It featured:

• A reinforced undercarriage for better stability
  
• Improved cab visibility with larger windows
  
• Simplified hydraulic routing for easier maintenance
  
• Compatibility with a wide range of buckets and attachments
  

Hitachi sold thousands of EX120 units globally, with strong uptake in North America, Southeast Asia, and Europe. Its success paved the way for later models like the ZX120 and EX130, which added electronic control systems and emissions compliance.
Common Applications and Field Performance
Operators favored the EX120 for:

• Urban excavation where space was limited
  
• Roadwork and drainage installation
  
• Agricultural land clearing and grading
  
• Light demolition and material handling
  

Its balance of size and power allowed it to work alongside larger machines without becoming a bottleneck. A technician in Texas recalled using an EX120 to remove tree stumps and grade a rural driveway. The machine’s responsiveness and low fuel consumption made it a favorite among his crew.
Maintenance Insights and Upgrade Suggestions
To keep an EX120 running smoothly:

• Replace hydraulic filters every 500 hours
  
• Inspect track tension monthly and adjust as needed
  
• Clean radiator and oil cooler fins weekly in dusty environments
  
• Use high-quality diesel and monitor injector performance
  
• Upgrade lighting and cab insulation for modern comfort
  

Some owners retrofit their EX120 units with auxiliary hydraulic kits and quick couplers. A crew in British Columbia added a thumb attachment and joystick controller, improving material handling during rock wall construction.
Recommendations for Owners and Restorers
To preserve value and performance:

• Document serial number and production year for accurate parts sourcing
  
• Maintain a service log with fluid changes and component replacements
  
• Inspect boom and arm welds for fatigue or cracking
  
• Replace worn bucket pins and bushings to maintain breakout force
  
• Coordinate with Hitachi support or aftermarket suppliers for legacy parts
  

A restoration shop in Georgia rebuilt an EX120 with new hydraulic hoses, resealed cylinders, and a repainted frame. The machine returned to full duty and was later sold to a contractor for utility trenching.
Conclusion
The EX120 in Hitachi EX120 excavator stands for a 12-ton class hydraulic crawler built for versatility, reliability, and global deployment. Its naming reflects a legacy of engineering clarity and performance consistency. Whether digging trenches or grading slopes, the EX120 proves that behind every model number lies a machine built to work hard and last long.