1995–1997 Hitachi EX300-3 / EX300LC-3 Excavator Technical & Workshop Manual (P/N 140T-01–01 / 140T-02–01)

This combined technical and workshop manual covers 1995–1997 Hitachi EX300-3 and EX300LC-3 excavators, with specifications for serial numbers 15K 07001 and higher.

The 860-page PDF contains English-language scanned pages. The technical content is image-based and cannot be searched as PDF text.

• Hydraulic repair: Main pump, regulator, pilot pump, control valve, and solenoid valve disassembly and assembly, with component inspection standards.

• Swing and travel: Reduction-gear and hydraulic-motor overhaul, brake-valve service, parking-brake operation, and swing and travel performance checks.

• Undercarriage and attachments: Swing-bearing and center-joint service, track-adjuster and roller repair, front-attachment removal, and boom, arm, and bucket cylinder rebuilding.

• Engine repair: Isuzu 6SD1-TPD disassembly, cylinder-head and crankshaft inspection, piston and bearing service, timing-gear installation, and compression testing.

• Electrical diagnosis: Dr.EX fault codes, engine controller (EC) and pump and valve controller (PVC) checks, live-data monitoring, connector pin layouts, and wiring diagrams.

• Operational performance: Pilot and main relief pressure tests, pump flow measurement, motor drainage checks, actuator cycle times, and hydraulic drift testing.

This manual is written for experienced technicians performing machine maintenance and repair.

Hydraulic Controls and Pump Testing

It details the interaction between the Isuzu 6SD1-TPD engine and the HPV145D hydraulic main pump system. Chapters define main relief valve parameters, flow combiner operation, and pilot-actuated control valve operation.

Control descriptions explain E-P regulation, speed sensing, work modes, and automatic travel-motor swash-angle changes. The main-pump test specifies portable tester ST 6299, speed-corrected flow calculations, adjustment data, and a Pump P-Q Curve.

Dr.EX Troubleshooting and Electrical Circuits

Troubleshooting A addresses signal-system fault codes; B covers machine symptoms without a displayed code; C covers gauges and indicators. This separation helps technicians choose the appropriate diagnostic checks when a machine travels slowly or loses a function without logging a fault code.

Harness checks cover continuity, voltage, resistance, and simulated signals. EC sensor positioning and voltage adjustment are also documented. The Electric Wiring Diagram, Engine Harness, and Cab Harness sheets support circuit tracing, alongside the hydraulic section's Hydraulic Circuit drawings.

Undercarriage and Cylinder Service

Exploded assemblies and maintenance standards support inspection of swing and travel devices, center joints, front idlers, rollers, and track links. Front-attachment coverage includes pin and bushing wear limits, cylinder seal inspection, and piston-rod straightness checks.

The floating-seal precautions explain how incorrect seal seating can cause oil leakage or damage in the front idler assembly.

Engine, Fuel, and Cooling Repairs

The engine chapters cover cylinder-liner removal and installation, crankshaft-bearing measurements, piston and ring inspection, reassembly, and engine tuning. The Timing Gear Train Explanatory Diagram shows the gear relationships. The Tufftride crankshaft has a specific repair restriction: regrinding and undersize bearings are not permitted.

Fuel-system coverage includes injection timing, nozzle testing, inspection, and reassembly. The engine reassembly notes warn that incorrect injection-pipe clip positioning can cause pipe breakage and fuel-pulsing noise.

Water-pump and oil-pump repair, thermostat inspection, oil-cooler checks, and IHI RHC7 turbocharger shaft-play inspection are covered separately. Engine specification notes distinguish standard-engine data from installation-dependent items and refer injection settings to the engine's maintenance data plate.

Fitment References and Service Specifications

The EX300-3/EX300-2 interchangeability tables identify shared components, new solenoid valves, and pump-system changes. References to earlier models concern component interchangeability and attachment fit, rather than extending the repair procedures to those machines.

Service data include component torque tables, fluid capacities, wear limits, engine performance curves, and electrical switch and sensor specifications. Engine tooling references include cylinder-liner remover 1-85231-016-0 and installer 1-85221-073-0.

The safety sections address high-pressure fluids, supported attachments, heavy-component lifting, and electrical isolation before welding.

File Contents and Readability

Page breakdown: Technical Manual, 373 pages (PDF pages 1–373), including three large-format electrical and harness diagram sheets; Workshop Manual, 487 pages (PDF pages 374–860), including the engine and accessory chapters. Introduction, safety, divider, and blank pages are already included in the 860-page total.

Navigation: 417 embedded PDF bookmarks provide access to the technical and workshop sections.

Scan quality: The large-format diagrams require zooming. Some small, densely printed labels remain difficult to distinguish at higher magnification. Scanned pages carry third-party promotional headers and footers.