Hitachi EX135UR Excavator 1997 Service & Repair Manual (P/N TO191-00)

• Official OEM technical manual in PDF format (Publication No. KM-191E, Vol. No. TO191E, TT191E, W191E) for the 1997 Hitachi EX135UR Cab Mounted excavator
• Covers operational principles, system logic, and component operation diagnostics across 949 pages
• Includes 36 detailed electrical system diagrams and 24 hydraulic circuit schematics documenting flow and control paths for complex troubleshooting and repair reference
• Documents 4BG1T Isuzu engine performance data alongside electrical sensor reference values
• Provides foundational logic for the electronic control and auto-MARCCINO systems
• Unit identification parameters covered: 2490 mm overall width and a 14000 kg operating weight
• Details the center joint, track adjuster, swing bearing, pilot shut-off valve, and shockless valve
• Features essential wiring diagrams, base machine dimension drawings, engine performance curves, main pump P-Q diagrams, electrical system component layouts, and hydraulic system layouts

Operational Systems Documentation

This publication provides an in-depth look at core machine operating principles. It covers the electronic control system, breaking down engine management, Auto-Idle functionality, and Noise Reduction protocols. Hydraulics are mapped out extensively. The document details the circuit logic for main pump operation and control valve spool mapping. It also explains the integration of the blade circuit within the primary hydraulic system. By offering precise step-by-step diagnostic and testing procedures—such as valve clearance adjustments, fuel injection timing calibration, engine compression pressure tests, nozzle checks, and main pump flow tests—this manual gives technicians a massive shop advantage. Instead of resorting to expensive dealership labor or blind parts swapping, mechanics can verify system health by comparing real-time operational data directly against factory specifications.

The front attachment control logic is fully documented. The auto-MARCCINO control unit manages movement restrictions, cabin collision prevention, and arm locus tracking. Every subsystem is described functionally. You see exactly how sensor inputs influence output signals for pumps and solenoid valve units, which is critical when analyzing systemic faults during a repair assessment. When diagnosing the EX135UR, mechanics frequently fall into a specific repair pitfall regarding the Auto-MARCCINO system: if a boom, arm, or offset angle sensor is replaced without performing the mandatory initial setting procedure, the system will trigger Fault Codes 60, 61, or 62 and lock out all front movements, often leading to a misdiagnosed hydraulic failure. Similarly, failing to run the engine learning operation after an EC motor replacement will cause the governor lever to default to an incorrect idle position, resulting in severely reduced engine speeds across all ranges. Always verify system pressure states and consult certified safety protocols before interacting with high-pressure hydraulics or live electrical systems.

Specification Highlights

Critical performance thresholds for the 62.5 kW Isuzu 4BG1T engine are thoroughly outlined. The manual provides exact baseline figures, such as the 18.1 MPa injection pressure and valve clearances set at 0.4 mm. Hydraulic data covers the HPV050FW-RH18D main pump, detailing a theoretical maximum flow of 95 L/min per pump section. System pressure limits are exact. The main relief pressure operates at 34.3 MPa, while overload relief settings reach up to 41.2 MPa for blade operations.