1997 Hitachi EX135UR Excavator Service & Repair Manual Set (P/N KM-191E)

This 1997 Hitachi EX135UR service and repair manual set (Manual No. KM-191E) covers the cab-mounted excavator with offset-type front attachment. It combines the Operational Principle and Troubleshooting technical manuals with the Workshop Manual.

• Engine service: Isuzu 4BG1T disassembly, internal inspection, reassembly, valve-clearance adjustment, injection-timing checks, compression testing, and nozzle testing.

• Hydraulic repair: Main-pump and regulator overhaul, control-valve assembly, pilot-valve repair, pressure testing, and main-pump flow checks.

• Travel and swing: Removal, disassembly, and assembly of reduction gears, travel and swing motors, the swing bearing, and center joint.

• Undercarriage: Track-adjuster service, front-idler and roller repair, rubber-track replacement, and component-specific maintenance standards.

• Front attachment: Attachment and cylinder removal, cylinder disassembly and seal installation, and pin-and-bushing inspection standards.

• Electronic diagnosis: Dr.EX fault-code retrieval, controller monitoring, Auto-MARCCINO diagnosis, angle-sensor initialization, and engine-learning procedures.

• Electrical reference: Circuit inspection, connector views, cab and engine harness drawings, and electrical sensor reference values.

Hitachi wrote these volumes for experienced technicians performing machine maintenance and repair.

Electronic Control and Auto-MARCCINO Diagnosis

The operational sections explain engine management, Auto-Idle, Noise Reduction, arm regeneration, and travel-motor swash-angle control. Front-control coverage follows movement restrictions, bucket/cab collision prevention, and arm locus tracking through sensor inputs and solenoid outputs.

Dr.EX procedures cover live monitoring and service-mode attachment and bucket configuration. The front-attachment code table distinguishes standard, slide-arm, and long-arm settings; these entries describe controller configuration for the optional attachments.

Symptom charts connect weak or slow machine functions with suspected electrical, pump-control, and valve faults. This helps distinguish a control-system problem from a hydraulic component fault before parts are removed. Harness checks identify dedicated test equipment, including lamp harness ST 7126 (P/N 4283594) for single-wire circuit checks.

Fault codes 60–62 identify incorrect boom, arm, or offset angle-sensor initialization, with movement toward the cab stopped. The engine-control section also explains how omitted or incorrect engine learning can leave engine speeds below normal across the operating range.

Pump, Valve, and Machine Component Repair

Pump procedures include regulator assembly, seal installation, and maintenance-standard tables. Functional sections explain control-valve spool circuits, blade-circuit integration, the pilot shut-off valve, and the shockless valve. The workshop precautions warn that starting with air trapped in the hydraulic pump housing can damage the pump.

Component drawings and inspection tables support wear assessment during reassembly. Reference material includes the Base Machine Dimension Diagram, engine performance curves, Main Pump P-Q Diagram, electrical component layouts, hydraulic system layouts, and the EX135UR Electrical Circuit drawing.

Follow the manual’s hydraulic-pressure release and lifting precautions when opening circuits or handling heavy assemblies.

Isuzu Engine Overhaul and Fuel-System Scope

The engine section goes beyond performance data, covering cylinder-head, liner, piston, crankshaft, and timing-gear inspection and repair. Lubrication and cooling chapters include oil-pump, oil-cooler, water-pump, and thermostat service, alongside starter and alternator reference drawings.

Piston selection is tied to measured cylinder-liner bore size. The manual warns that an incorrect piston grade can cause piston seizure.

Engine-specific injection-pump calibration sheets are included, while injection-pump adjustment and repair are assigned to an authorized Bosch or Zexel service outlet. Detailed Mitsubishi TD-series turbocharger repair is referred to a separate publication.

A Preview of Engine and Hydraulic Reference Values

These examples represent a small selection of the engine and hydraulic specifications in the set.

For the 4BG1T engine, the test data specify 0.4 mm intake and exhaust valve clearance with the engine cold, plus a standard nozzle injection pressure of 18.1 MPa. The HPV050FW-RH18D main-pump specifications list a theoretical maximum flow of 95 L/min per pump section.

Control-valve data specify main relief pressure at 34.3 MPa with 80 L/min flow. The blade-raise overload relief specification is 41.2 MPa at 50 L/min.

Search Coverage, Bookmarks, and PDF Contents

Search and diagram detail: Text search is available through most of the two technical volumes; the Workshop Manual pages do not contain searchable text. Embedded bookmarks cover all three volumes. Small wire, pin, and connector labels on the large-format circuit and harness sheets require zooming.

The set is supplied as one printable, 949-page PDF containing the following publications:

These totals already include three volume covers, 51 blank pages, 27 memo pages, and three revision-request forms. The five large-format circuit and harness sheets are included in the Troubleshooting volume’s page count.