1998 Kobelco SK70SR Hydraulic Excavator Shop Manual (P/N S5YT0001E(1)

This factory-issued Kobelco/Kobe Steel shop manual set covers SK70SR excavators in the YT00101-and-up serial range. Coverage includes the 1.65 m standard arm, 2.07 m long arm, 450 mm and 600 mm crawler-shoe arrangements, bucket combinations, dozer equipment, and standard or additional hydraulic configurations. Its repair depth and reliance on cranes, hydraulic gauges, electrical test equipment, and model-specific jigs make it best suited to experienced excavator technicians and equipped repair shops.

• Document identity: Book Code S5YT0001E(1), with 1998 core books and the S5YT6301E breaker/nibbler supplement issued in 1999. The 870-page PDF contains 4 pages of front index/safety material; 51 specification, 52 maintenance, 225 system, 247 disassembly/assembly, 49 troubleshooting, 191 engine, and 51 optional-attachment pages.
• Engine repair: Machine specifications identify the Isuzu A-4JB1. The included engine book covers the broader 4JA1/4JB1/4JC1 industrial-engine family, so the 4JB1-specific tables and procedures are the relevant set for this excavator. It covers disassembly, inspection and repair, reassembly, valve and timing work, fuel injection, lubrication, cooling, starter/alternator service, compression testing, and fault diagnosis.
• Hydraulic and mechatro diagnosis: Covers the pump/regulator, pilot and main control valves, swing and travel motors, swivel joint, cylinders, boom/arm safety valves, and standard, extra, dozer, and breaker circuits. Factory procedures include pressure testing, drain checks, performance measurement, controller service diagnostics, error codes, and Mechatro Controller A adjustment.
• Machine disassembly: Removal and installation coverage includes the front attachment and upper swing body - cab, counterweight, tanks, engine, pump, valves, swing motor, swivel joint, and upper frame. The travel-frame book handles the crawler, rollers, idler/adjuster, sprocket, travel reduction unit, and swing bearing, with component disassembly and reassembly where provided.
• Electrical and climate control: Includes the main electrical circuit, harness connection drawings, controller and instrument-panel connections, starting/charging equipment, lighting, and system-specific fault tracing. The R134a air-conditioning chapter covers component construction, unit-case removal/installation, refrigerant charging, functional checks, wiring/connectors, and troubleshooting.
• Optional attachment conversion: The dedicated field-conversion book covers breaker and nibbler/breaker builds. It documents additional-parts lists, the cab guard, control-valve and piping changes, 1.65 m/2.07 m arm and boom modifications, idler-link reinforcement, selector-valve use, flushing, hydraulic-oil and return-filter service, and operating precautions.
• Tools and shop data: Provides Kobelco jig drawings for counterweight and upper-frame lifting, boom-foot and cylinder-pin removal, engine support, and track-spring setup. The Isuzu tool list supplies part numbers such as compression gauge 5-8840-2008-1, 4JA1/4JB1 liner remover 5-8840-2039-0, and liner installer 5-8840-2040-0.

Specifications, Testing, and Diagrams

The specification books establish the correct build before repair parts or test procedures are selected. They include transportation and lifting data, working and lifting ranges, crawler and bucket types, attachment combinations, boom/arm/bucket/dozer dimensions, torque tables, SI/unit-conversion charts, approved compounds, component weights, capacities, pin-and-bushing clearances, wear limits, and standard labor times for machine and engine work.

Testing is organized around factory performance standards rather than isolated numbers. The manual covers engine-speed checks; pilot and main hydraulic pressure tests; travel speed, deviation, and drift; swing speed, overrun, drift, and motor drain; attachment cycle and cylinder drift; swing-bearing movement; and controller adjustment. Electrical service diagnosis and hydraulic/mechatro symptom charts support fault isolation before parts are removed.

Representative drawings include the Standard Spec. with Boom & Arm Safety Valve hydraulic circuit, the Extra & Breaker & Dozer circuit, the Electric Circuit Diagram, Harness Connection Drawing, Travel Straight Mechatro Control System, and Travel Motor construction views. Exploded assembly drawings accompany the attachment, upper-structure, undercarriage, and hydraulic-component procedures.

Repair Cautions and Scope

The hydraulic installation guidance requires bleeding after hydraulic-oil changes or service to suction-side piping, the pump, swing motor, travel motor, or cylinders; operating without oil or with trapped air can damage those components. The A/C material is specific to R134a and SP20 refrigerant oil and warns against substituting other refrigerants or oils because the cooling unit and circuit can be damaged or contaminated.

Major repair work also requires the lifting, blocking, pressure-relief, and electrical-isolation practices specified in the manual. Operating instructions and the full lubrication/maintenance program remain in the separate Operator’s Manual and Operation & Maintenance Guide; this PDF is the shop repair, systems, testing, and troubleshooting reference.