Hitachi EX120-2 Hydraulic Excavator Technical Manual (PI2N-1-7) – Complete 365 P. | Factory Grade

Hitachi EX120-2 Parts Catalog

This factory-direct reference provides the complete mechanical architecture for the Hitachi EX120-2, ensuring every repair or component replacement meets original equipment manufacturer standards. By utilizing the exact exploded views and engineering indices found in this technical volume, fleet managers and technicians can eliminate part-ordering errors and significantly reduce machine downtime. Relying on verified technical documentation is the only way to preserve the operational integrity and resale value of your hydraulic excavator.

Workshop Reference Standards

• Page Count: 365 Pages
• Document ID: PI2N-1-7
• Format: High-Resolution PDF
• Language: English / Japanese Dual-Language Reference

Precision Fleet Compatibility

This technical archive is specifically engineered for the Hitachi EX120-2 Excavator series. It covers the following regional configurations and serial breaks:

• Standard (STD) Specification Models
• Northern Europe (N. EUROPE) Regional Models (Finland, Sweden, Norway)
• Equipment Serial Number: 30001 and up
• Engine Reference: Isuzu 4BD1T Diesel (Cross-reference provided)

Long-Term Operational Benefits

• Parts Accuracy: Instant identification of superseded components to prevent ordering incorrect or obsolete hardware.
• Cost Mitigation: Detailed assembly views allow for "repair-not-replace" strategies by identifying individual sub-components.
• Assembly Integrity: Visual guides ensure that complex multi-part systems are reassembled in the precise factory-ordered sequence.
• Communication: Standardized part numbers facilitate clear communication with global logistics and hardware suppliers.

Visual Schematic Fidelity

The document features ultra-high-definition exploded view diagrams designed for maximum zoom capability on workshop tablets or high-scale printouts. Every pin, seal, and bushing is rendered with mechanical precision, accompanied by an alphanumeric indexing system that links directly to the parts list. This visual clarity is essential for identifying micro-components in high-pressure hydraulic circuits and complex undercarriage assemblies.

Critical Service Benchmarks

• Hydraulic Seal Integrity: Precise identification of O-ring and seal kit groupings to maintain system pressure at the required 350 kgf/cm².
• Engine-Chassis Interface: Detailed mapping of the Isuzu 4BD1T mounting and cooling connections to ensure thermal stability.
• Undercarriage Tolerances: Comprehensive layout of track links and rollers to monitor wear patterns and schedule preventative maintenance.
• Bucket Linkage Geometry: Breakdown of bushings and dust seals to minimize play and maximize digging precision.

Systems Integrity & Diagnostics

This manual facilitates deep-system diagnostics by mapping the relationship between the pilot control valves and the primary hydraulic pumps. Technicians can trace the logic of the variable flow control system through the physical layout of hoses and manifold blocks, allowing for rapid isolation of pressure drops or mechanical failures within the 12N series platform.

Comprehensive Component Index

• Superstructure: Frame, counterweight, and cab assembly breakdown.
• Undercarriage: Track frames, idlers, sprockets, and shoe groups.
• Hydraulic System: Main pump, control valves, swing motor, and travel device.
• Work Equipment: Boom, arm, bucket, and cylinder seal kits.
• Electrical & Tools: Wiring harnesses, lights, and operator controls.
• Numerical Index: Full part number cross-reference list for rapid searching.

FAQ

How do I confirm if this catalog covers my specific Hitachi EX120-2 regional variant? This technical reference is engineered for the 12N series and covers both the Standard specification and the specialized configuration for Finland, Sweden, and Norway. It specifically supports machines starting with Serial Number 30001 and higher, ensuring that regional variations in cab hardware or hydraulic plumbing are accurately identified for precise parts procurement.

What engine data is provided for the EX120-2 power unit? The documentation focuses on the integration of the Isuzu 4BD1T Diesel engine within the 12N chassis. While chassis-specific mounting and cooling hardware are detailed here, the 4BD1T is a 3.856L turbocharged unit with a rated output of ~88 HP at 2200 RPM; having this specific catalog allows you to cross-reference these power specs with the correct Hitachi-specific auxiliary components like the 24V starter and 40A alternator.

Where can I find the hydraulic pressure settings and pump configurations? The manual provides exploded views of the primary hydraulic system, which is designed to operate at a main relief pressure of 350 kgf/cm² (4,980 PSI). It details the internal components for the variable displacement axial piston pumps and the pilot system which regulates flow at 40 kgf/cm² (570 PSI). Accessing these schematics allows technicians to identify the exact seal kits required to maintain these high-pressure benchmarks during a rebuild.

Is this guide detailed enough for undercarriage and track maintenance? Yes, it contains high-resolution breakdowns of the lower rollers, idlers, and track link assemblies. It is essential for verifying the tolerances of the 5.5 km/h high-speed travel motors and ensuring the planetary reduction gears in the final drive are serviced with the correct 4.0L fluid volume per side. This level of detail prevents premature wear on expensive undercarriage components by ensuring every shim and dust seal is accounted for.

How does the high-resolution digital format improve field diagnostics? The digital archive features high-scale schematics that maintain clarity at 400% zoom, allowing shop mechanics to read small alphanumeric part codes on complex manifolds or wiring harnesses that are often illegible in greasy paper manuals. This instant access to the PI2N-1-7 document architecture means you can verify component locations directly at the machine, eliminating the need to travel back to a stationary office for technical verification.