Komatsu WA70-1 Wheel Loader Shop Manual (P/N SEBM04150104)

• Covers Komatsu WA70-1 wheel loaders, serial numbers 10001 and up, with the Komatsu 4D95L-W engine and TORQFLOW transmission.
• Komatsu shop manual publication SEBM04150104, © 1993 Komatsu, printed in Japan 05-93.
• The supplied PDF contains 498 scanned pages covering testing and adjusting, troubleshooting, disassembly and assembly, component structure/function, and maintenance standards across the machine’s major systems.
• Serial-specific information is built into the manual. It distinguishes S/N 10001–11999 from S/N 12001 and up in areas including component weights, transmission maintenance standards, work-equipment controls, main-control-valve procedures, and fluid capacities.

Component Structure and System Functions

For drivetrain diagnosis, the power-train section maps the torque converter and TORQFLOW transmission, then breaks down the transmission control valve, main regulator valve, quick-return valve and accumulator, power-modulating function, clutch cut-off valve, accumulator valve, control linkage, drive shafts, axles, differentials, and final drives.

Named diagrams and circuit views include the Hydraulic Circuit Diagram for Power Train, Torque Converter and Transmission Piping, Hydraulic Circuit Diagram for Steering, Brake Piping, the work-equipment Hydraulic Circuit Diagram, and the Electric Wiring Circuit Diagram. The electrical section also covers the cluster gauge, engine starting circuit, engine stop circuit, and preheating circuit.

Steering coverage includes the flow divider valve, steering valve, steering cylinder, and center hinge pin. Brake coverage reaches the master cylinder, wheel brakes, parking brake, and brake caliper. The work-equipment section details the hydraulic tank, filter and breather, main control valve with relief, safety, and suction valves, hydraulic pump, lift and dump cylinders, lever linkage, bucket linkage, and bucket positioner.

Factory Procedures, Testing, and Repair Depth

The factory procedures cover jobs that normally require more than routine maintenance information: cylinder-head removal and installation, fuel-injection-pump and nozzle-holder work, engine removal and installation, torque-converter and transmission overhaul, clutch-pack disassembly and assembly, transmission-valve work, front and rear axle removal, differential overhaul, steering-valve and steering-cylinder repair, center-hinge service, brake master-cylinder and parking-brake work, hydraulic-pump removal/installation, main-control-valve repair, lift and dump cylinder work, and instrument-panel removal and installation.

Testing and adjusting sections give diagnostic routines for engine compression and injection timing, torque-converter and hydraulic stall speed, transmission pressures and shift linkage, steering-wheel play and steering relief pressure, brake performance and brake oil pressure, hydraulic main-relief pressure, lift-arm and bucket cycle times, cylinder drift, control-lever travel, and bucket-positioner adjustment. Troubleshooting tables are included for the power train, steering, brakes, and work equipment.

The tool tables identify factory test equipment by part number, including hydraulic tester 799-101-5000, thermistor kit 799-101-6000, push-pull scale 7A0-262-0020, compression gauge 795-502-1204 with adapter 795-502-1380, and brake hydraulic tester 793-520-1801 with pump assembly 790-101-1102.

The repair cautions are specific. In the transmission clutch pack, forcing a piston out while it is cocked can damage the cylinder, and the manual warns against damaging the piston seal or trapping clutch plates or springs in the housing ring groove during assembly. Transmission-control-valve oil seals must be pressed in straight; the manual also warns against damaging the seal lips. In the drive-shaft section, welding the bearing-cap strap is specifically prohibited because the heat can damage the bearing.

Specification Previews and Technical Depth

Hard numbers are provided for setup, diagnosis, and reassembly. For the 4D95L-W, cold valve clearance is 0.35 mm intake / 0.50 mm exhaust, and fuel-injection timing is 14 ±1° B.T.D.C. Cylinder-head bolts use a three-stage tightening sequence with target values of 8, 12, and 15 kgm, the final range being 14.5–15.5 kgm.

Power-train pressure specifications include 23 ±2 kg/cm² main-regulator pressure, 22 ±2 kg/cm² clutch pressure, and 4 +0.8/−0.5 kg/cm² torque-converter outlet pressure. Steering main-relief pressure is 120 ±5 kg/cm², while the work-equipment main-relief setting is 210 +7/0 kg/cm².

The lubricant and water chart lists 21 L specified / 12 L refill for the transmission case, 32.5 L / 19 L for the hydraulic system, and 8 L per axle. Serial-specific capacities matter: S/N 10001–11999 uses a 60 L fuel tank and 14 L cooling system, while S/N 12001 and up is listed at 63 L and 12 L. The weight table likewise shows the engine at 287 kg and the counterweight changing from 551 kg to 620 kg across that serial break.

Engine coverage is focused on testing/adjusting and removal/installation of major engine-related assemblies; it is not a full 4D95L-W bottom-end overhaul section. Before pressure testing or repair work, the manual repeatedly calls for the machine to be secured, the bucket lowered or properly supported, the parking brake applied, the tires blocked, and hydraulic pressure released before lines, plugs, or gauges are opened.