1999–2002 Hitachi EX40U, EX50U Excavator Technical Manual (P/N T585E-00, T585E-NA)

• Two-file factory manual set, 937 PDF pages total — a 467-page EX40u/EX50u edition and a 470-page EX50u North America edition. The technical volume identifiers printed with the attached schematics are T585E-00 and T585E-NA; both files repeat the same 122-page engine section.
• Coverage separates EX40u Type A, EX40u Type B, EX50u, and the EX50u North American configuration, with canopy/cab specification tables and EX40u schematic breakouts for serial numbers 101–1000 and 1001 and later.
• Hydraulic-system material explains the PG/P1/P2 pump circuits, pilot circuits, boom anti-drift and flow-combiner valves, main and overload relief valves, swing and travel devices, center joint, track adjuster, and the North American SAE/ISO rotary control-pattern valve.
• Factory diagnostics cover engine compression, valve-clearance, nozzle, and injection-timing checks; travel, swing, drift, and leakage tests; hydraulic-cylinder cycle times; pilot and relief-pressure testing; monitor and electrical fault tracing; and the North American travel-alarm circuit.
• Workshop repair procedures include removal, installation, disassembly, assembly, inspection, and maintenance standards for pump devices, control valves, swing motors and reduction gears, pilot and solenoid valves, travel drives, center joints, rollers, rubber tracks, front attachments, and hydraulic cylinders.
• Attached reference material includes serial-specific hydraulic and electrical circuits, engine/main/frame harness drawings, an air-conditioner harness, component section views, exploded assemblies, torque data, hydraulic test specifications, wear limits, and special-tool references.

Variant-Specific Systems and Diagnostics

When troubleshooting the Hitachi EX40u or EX50u, accurate variant data matters. These manuals divide the machine into general specifications, hydraulic-system operation, component operation, operational performance tests, troubleshooting, and workshop repair. Type A and Type B are not treated as interchangeable. The Type A pilot circuit releases the swing parking brake through the control-valve pilot signal, while Type B and EX50u use a pilot shut-off solenoid circuit. The attached EX40u drawings further separate serial numbers 101–1000 from machines numbered 1001 and later.

The North American EX50u edition contains configuration-specific material. Its component layouts identify the travel alarm, buzzer-cancel switch, separate front/swing and travel pilot valves, and the rotary valve used to select SAE or ISO lever patterns. Its troubleshooting section adds a dedicated travel-alarm diagnostic chart covering the controller, pilot-pressure inputs, cancel switch, buzzer, and related harness checks.

Workshop Repair and Engine Coverage

The workshop material goes well beyond system theory. It covers pump removal and internal assembly, plus control-valve service down to the relief and make-up valves, direct-acting and pilot-operated spools, and flow-combiner valve. Swing work includes the reduction gear, bearing preload, motor, and parking-brake switch valve. Undercarriage and attachment sections address the travel reduction unit, center joint, track adjuster, idlers, rollers, rubber crawler, front attachment, and boom, arm, bucket, boom-swing, and blade cylinders.

Special-tool callouts are tied to actual factory tests and repair work. Examples include ST6077 with ST6933 for main-pump pressure checks, ST6627 for swing and travel motor case-drain testing, and ST7924 for controlled pilot-valve disassembly and assembly. Related sections provide component-specific torque tables, piping-joint data, maintenance standards, inspection limits, and adjustment specifications.

The repeated 122-page engine section contains 4LE1-specific entries within its Isuzu engine-family tables. It covers internal engine disassembly, inspection and repair, reassembly, lubrication and cooling circuits, oil pump, water pump, thermostat, fuel circulation, governor, nozzle-holder service, troubleshooting, and special tools. This is internal engine repair coverage; the machine workshop contents do not include a dedicated excavator engine removal/installation chapter. Canopy removal is documented, but there is no separate cab-removal chapter.

Schematics, Repair Notes, and Safety

Key attached drawings include the EX40u serial 101–1000 hydraulic circuit, the EX40u 1001-and-later hydraulic circuit, the EX50u hydraulic circuit, the early EX40u electrical circuit, the later EX40u/EX50u electrical circuit, and the North American EX50u electrical circuit.

The manual flags several repair traps that matter in the shop. Air must be bled after pump, hydraulic-motor, or cylinder work to avoid component damage. The swing-motor brake piston is installed with a press rather than driven in, and pilot-valve spools, shims, and related parts must remain matched to their original ports.

Hydraulic pressure, spring-loaded valves, suspended structures, and heavy components create serious hazards. Follow the manual’s pressure-release, lifting, blocking, and assembly precautions, and use a qualified technician when the repair exceeds your tools or experience.