Komatsu WA400-1 Wheel Loader Shop Manual, 1990–2005 (P/N SEBM04240106)

Komatsu shop manual P/N SEBM04240106, bearing print code 08-90(03)05501, covers the WA400-1 wheel loader, serial 10001 and up. Detailed internal engine repair requires the separate 110 Series Engine Shop Manual referenced on the cover; that publication is not included.

PDF Bookmarks and Diagram Detail

Search, navigation and drawings: PDF text search is not available. Embedded bookmarks provide chapter and procedure navigation. Small wiring labels, connector identifiers and pin numbers require zooming; some lines in the air-conditioning circuit drawing are faint.

The ZIP download contains one printable English-language PDF with 780 pages total, including 14 original cover, contents, revision-list and introductory/reference pages. These pages are already included in the total.

Drivetrain, Hydraulic and Electrical Workshop Coverage

The following selected workshop topics are a preview rather than a complete contents list. Further examples include wheel lock-ring fit checks and replacement speedometer-module adjustment.

• Engine testing: Compression and injection-timing checks, valve-clearance adjustment, lubrication and blow-by testing, and fuel-system adjustments for the SA6D110-1 installation.

• Power-train repair: TCA37-1A torque converter and KTM4422 transmission diagnosis, clutch repair, differential setup, axle service and planetary final-drive overhaul.

• Steering and articulation: Steering pressure and linkage checks, steering-gear and cylinder repair, center hinge-pin replacement, and optional emergency-steering system documentation.

• Brakes and air system: Service-brake and parking-brake testing, brake bleeding, disc-wear measurement, and overhaul of valves, brake chambers and related components.

• Work-equipment hydraulics: Pressure and drift tests, lift and dump cylinder repair, control-valve overhaul, bucket-positioner adjustment and boom kick-out setting.

• Electrical diagnosis: Wiring diagrams, connector views, starting and preheat circuits, transmission and parking-brake controls, plus EVMS fault-isolation charts.

Written for workshop service personnel, this manual calls for pressure-testing equipment, lifting gear and component repair stands appropriate to the procedures being performed.

Engine Installation, Fuel System and Cooling

The engine chapters address the water-cooled, direct-injection, turbocharged and aftercooled SA6D110-1 installation, including its mounts, controls, fuel tank and piping.

Removal and installation procedures cover the cylinder head, turbocharger, aftercooler, air compressor, radiator, oil cooler and complete engine assembly. Separate procedures address the starter, alternator, injection pump, nozzle holders and water pump.

Testing also includes engine-oil temperature, exhaust color, fan-belt tension, accelerator-pedal force and travel, and fuel-cut solenoid adjustment.

Transmission Diagnosis and Bench Repair

Stall-speed and oil-pressure tests accompany symptom tables for no travel, low power or speed, delayed engagement and shifting, and excessive torque-converter oil temperature. A dedicated fault-isolation chart separates transmission electrical-control problems from faults in the transmission or hydraulic control valve before disassembly.

Hydraulic explanations follow the converter charging pump, relief and priority valves, modulating and quick-return valves, accumulator valve, pilot reducing valve, solenoids and emergency manual spool.

Step-by-step procedures cover removal of the combined converter, transmission and transfer assembly, followed by bench disassembly and reassembly of the converter, clutch transmission, control valve, transfer, differentials, drive shafts, axles and final drives.

Assembly details: Clutch seal-ring orientation is specified for correct pressure application. Differential instructions treat the ring gear and pinion as a matched set and preserve total shim thickness during tooth-contact correction to maintain bearing preload. The final-drive assembly procedure warns that excessive bearing-cap press force can damage the retaining snap ring.

Steering, Center Hinge and Brake Service

Steering checks cover wheel play, operating force, turning time, linkage adjustment and hydraulic pressure. Repair sections extend to the recirculating-ball steering gear, steering valve, cylinders and center hinge pins.

Linkage drawings distinguish serial 10001–10300 from 10301 and up. Upper hinge-pin mounting-bolt specifications also distinguish serial 10001–10405 from 10406 and up. Optional emergency-steering documentation includes the pump, diverter valve and security valve.

The air-operated hydraulic wet-disc brake sections combine braking-performance, oil-pressure and disc-wear checks with bleeding and component repair. Coverage includes the air governor, brake valves, brake chambers and master cylinders, slack adjusters, spring cylinder, caliper and drive-shaft parking brake.

Loader Hydraulics and Gear-Pump Overhaul

Work-equipment procedures address the hydraulic tank and filters, hydraulic/switch/steering pump assembly, main control valve, relief and suction valves, lift and dump cylinders, and bucket linkage.

Lever settings, lift-arm and bucket operating checks, hydraulic-drift diagnosis, bucket-positioner and boom kick-out adjustments accompany removal and installation of the work equipment and counterweight.

Circuit drawings distinguish the two-spool arrangement from the optional three-spool attachment circuit, including an emergency-steering configuration. The SA Series gear-pump section adds bench testing, disassembly, reassembly, side-clearance inspection and post-assembly delivery testing.

Electrical Circuits, Connectors and EVMS

Electrical coverage follows engine starting and stopping, manual and automatic preheating, transmission cut-off and neutralizer control, and electrical parking-brake operation.

Connector terminal numbering, harness and sensor locations, connector-handling precautions and YES/NO diagnostic charts support fault tracing. The E-1 through E-15 charts address electrical-system faults; M-1 through M-33 cover the Electronic Vehicle Monitoring System, including warning lamps, gauges, buzzer, speedometer, service meter and monitor-panel faults.

Drawings include the Hydraulic Circuit Diagram for Power Train, Hydraulic Circuit Diagram for Steering, Work Equipment Hydraulic Circuit Diagram, Electrical Transmission Control Diagram, electrical connector-location views and Air Conditioner Wiring Diagram.

Cab, Air Conditioning and Workshop References

Cab removal and installation are included, along with removal and refitting of the air-conditioning unit, condenser, dry receiver and compressor on equipped machines.

Standard-value and maintenance-standard sections provide torque tables, pressure-test data, fluid capacities, wear and clearance limits, bearing-preload specifications and gear-contact guidance.

Tool references include tachometer 799-203-8000, hydraulic tester 799-101-5000, thermistor kit 799-101-6000, engine-pressure measuring kit 799-203-2002, brake hydraulic tester 793-520-1801 and unit repair stand 790-501-5000.

For testing and repair, the manual specifies machine restraint, the frame safety bar, supported work equipment and suitable lifting equipment. Hydraulic and air pressure must be released before opening pressurized connections.

A Preview of Valve-Clearance and Compression Specifications

For SA6D110-1 valve adjustment, the manual specifies 0.25 mm intake and 0.45 mm exhaust clearance with the engine cold.

The compression-test table gives a minimum standard pressure of 28 kg/cm² and a permissible minimum of 22 kg/cm² at 300–350 rpm, with coolant at operating temperature and valve clearances at specification. These procedures appear on PDF pp. 34–35.