Exploring the Hitachi EX135USR-5 Excavator

[MikePhua]

Hitachi’s Compact Excavator Evolution
The Hitachi EX135USR-5 is part of the EX series, a line of hydraulic excavators that helped define compact performance in urban and restricted job sites. Hitachi Construction Machinery, founded in 1970 as a division of Hitachi Ltd., became globally recognized for its precision engineering and hydraulic innovation. The EX135USR-5 was introduced in the early 2000s as a short-radius variant of the EX135UR, designed to meet growing demand for machines that could operate efficiently in tight spaces without sacrificing digging power.
The “USR” designation stands for “Ultra Short Radius,” indicating a reduced tail swing profile. This feature allows the machine to rotate within its own footprint, minimizing the risk of collision with nearby structures or vehicles. The dash-5 generation brought refinements in hydraulic control, emissions compliance, and operator comfort, aligning with global Tier 2 standards and expanding Hitachi’s footprint in North America, Europe, and Asia.
Sales of the EX135USR-5 were strong in regions with dense urban development, particularly Japan, South Korea, and parts of Western Europe. Its compact dimensions and robust undercarriage made it a favorite among contractors working on utility trenching, foundation excavation, and roadwork.
Comparing the EX135USR-5 to EX135UR and EX120-5
While the EX135USR-5 shares its core architecture with the EX135UR, the key difference lies in the tail swing and counterweight configuration. The UR model has a conventional tail swing, requiring more clearance during rotation. The USR variant reduces this radius by nearly 30%, making it ideal for alleyways, building perimeters, and roadside operations.
Compared to the EX120-5, the EX135USR-5 offers:

• Increased operating weight (approximately 13,500 kg vs. 12,000 kg)
  
• Higher bucket breakout force (around 9,800 kgf vs. 8,500 kgf)
  
• Longer reach and deeper digging depth
  
• Enhanced hydraulic flow capacity for faster cycle times
  

Terminology annotation:

• Tail Swing Radius: The distance from the center of rotation to the furthest rear point of the machine during swing.
  
• Bucket Breakout Force: The maximum force exerted by the bucket during digging, critical for penetrating hard soil or rock.
  
• Hydraulic Flow Capacity: The volume of hydraulic fluid moved per minute, affecting actuator speed and responsiveness.
  

Product Identification and Build Year Estimation
The Product Identification Number (PIN) for the EX135USR-5 typically begins with “1ENP,” followed by a six-digit serial. Based on production records and field data, units with serial numbers in the 001000–001500 range were likely manufactured between 2002 and 2004. Hitachi’s serial number system is not always linear, but regional distributors often maintain build year databases that can confirm exact dates.
In one case from New Zealand, a contractor acquired an EX135USR-5 with a PIN ending in 001014. After contacting a local Hitachi dealer, they confirmed the machine was assembled in late 2003 and shipped to Oceania in early 2004 as part of a municipal infrastructure fleet.
Hydraulic System and Operator Controls
The EX135USR-5 features a load-sensing hydraulic system with variable displacement piston pumps. This setup allows the machine to adjust flow and pressure based on demand, improving fuel efficiency and reducing heat buildup. The pilot controls are responsive and ergonomically positioned, with proportional thumb switches for auxiliary functions.
Operators report smooth joystick feedback and minimal lag during multi-function operations. The boom, arm, and bucket can be feathered precisely, making the machine suitable for grading and finish work.
Recommendations for hydraulic maintenance:

• Replace hydraulic filters every 500 operating hours
  
• Use ISO 46 hydraulic oil in temperate climates, ISO 68 in hotter regions
  
• Inspect pilot lines for leaks or abrasion quarterly
  
• Flush and refill the system every 2,000 hours or annually
  

Undercarriage and Structural Durability
The EX135USR-5 rides on a reinforced undercarriage with sealed track rollers and heavy-duty idlers. Track tension is maintained via grease-filled cylinders, and the sprockets are heat-treated for extended wear life. The boom and arm are constructed from high-tensile steel with internal baffles to resist torsional stress.
In a case from British Columbia, a contractor used an EX135USR-5 for riverbank stabilization. Despite operating in rocky terrain and submerged conditions, the undercarriage showed minimal wear after 1,800 hours, thanks to regular cleaning and tension checks.
Cab Comfort and Visibility
The operator cab is pressurized and equipped with climate control, adjustable suspension seat, and wide-angle windows. Visibility is enhanced by the short tail design, allowing better rearward awareness. Noise levels inside the cab average around 72 dB during full operation, making it one of the quieter machines in its class.
Suggestions for cab upkeep:

• Replace cabin air filters every 250 hours
  
• Lubricate door hinges and seat rails monthly
  
• Inspect window seals for dust ingress
  
• Calibrate monitor display brightness for changing light conditions
  

Conclusion
The Hitachi EX135USR-5 is a compact powerhouse engineered for precision and agility. Its ultra-short radius design, robust hydraulics, and operator-friendly controls make it a standout choice for urban excavation and utility work. With proper maintenance and attention to hydraulic and structural integrity, this machine can deliver thousands of productive hours—even in demanding environments. Whether you're grading a tight alley or trenching beside traffic, the EX135USR-5 proves that compact doesn’t mean compromised.