2003 Komatsu WB140-2N / WB150-2N Shop Manual (P/N CEBM009802)

• Exact machine coverage: Applies to Komatsu WB140-2N, serial A20001 and up, and WB150-2N, serial A60001 and up. This is the 406-page PDF of the May 2003 Komatsu America chassis Shop Manual, form number CEBM009802.

• Power-train and axle repair: Covers the torque-converter transmission, forward/reverse and 4WD drive sections, transmission control valve block, and front and rear axles. Factory procedures include transmission and converter removal/installation, planetary and wheel-hub service, brake-control work, differential carrier setup, ring-and-pinion assembly, bearing preload, and backlash checks.

• CLSS hydraulic testing and adjustment: Explains the piston pump, PC and LS valves, servo piston, working-mode solenoid, unloading, pressure cut-off, decompression, delivery-compensation, LIFD, and priority-valve functions. Test sections cover main and secondary relief settings, load-sensing adjustment, steering pressure, and brake-circuit leak checks, with pump-delivery specifications for the covered configurations.

• Loader and backhoe repair procedures: Includes removal and installation of the front work equipment, backhoe assembly, boom, arm, buckets, swing bracket, outriggers, and telescopic arm. The manual also covers cylinder removal plus disassembly and reassembly of the raise, tilt, boom, arm, bucket, outrigger, swing, and telescopic-arm cylinders.

• Operational diagnosis and adjustment: Provides engine and chassis standard-value tables, power-train clutch and converter tests, return-to-dig sensor adjustment, hydraulic-drift isolation, brake bleeding, pedal and microswitch adjustment, and air-conditioning pressure/temperature fault charts.

• Schematics and workshop references: Named drawings include the Diagram of the Power Train, Hydraulic Converter-Transmission Circuit Diagram, separate Hydraulic Circuit (WB140-2N) and Hydraulic Circuit (WB150-2N) sheets, the main Electrical Schematic, and the Air Conditioner Circuit. Standard torque charts, coating-material data, wire codes, component limits, and special-tool tables are also included.

What This Chassis Manual Covers

Komatsu prepared this shop manual for service-workshop personnel. Its pressure and flow testing, refrigerant recovery, heavy-component lifting, hydraulic-press work, and axle setup procedures make it suited to trained technicians or experienced mechanics with the required shop equipment.

Engine reference data is separated by configuration: the naturally aspirated WB140-2N uses the 4D106-1FA, the turbocharged WB140-2N uses the S4D106-1FH, and the WB150-2N uses the S4D106-1FA. Chassis-level engine coverage includes speed checks, valve-clearance adjustment, compression testing, injection-timing checks, belt adjustment, and removal/installation of the engine and transmission as an assembly.

This is not the internal engine overhaul volume. For cylinder-head, oil-pump, injection-pump, injector, governor, turbocharger, water-pump, oil-seal, and related internal engine procedures, Komatsu directs the technician to the separate Engine Shop Manual, WEBM4D9801.

Hydraulic configuration is also explicit. The front shovel uses two- or three-spool control-valve arrangements. Backhoe coverage includes six-spool, seven-spool versions for a telescopic arm or hammer, and the eight-spool hammer-plus-telescopic-arm arrangement. That distinction matters when selecting the correct circuit, test point, or repair procedure.

Diagnostics, Setup Data, and Repair Cautions

The manual supplies factory reference categories for control and pedal travel, brake and steering performance, transmission and converter pressures, hydraulic relief and load-sensing behavior, pump delivery, cylinder condition, and axle setup. Troubleshooting charts isolate front-axle, rear-axle, and transmission faults, while hydraulic-drift tests distinguish control-valve leakage from cylinder-seal leakage.

Special-tool listings identify the required measuring and assembly equipment, including the ATR201490 air-bleeding tank cap, ATR200620 / 960119000 cylinder service attachment, CA715023 front-axle false pinion, and CA715128 rear-axle false pinion.

The torque converter must seat in the transmission without being forced, or the front pump can be damaged. During hydraulic-cylinder reassembly, the seal rings must face the specified direction and the sliding surfaces must be protected; careless handling can damage the new seals and cylinder surfaces.

Raised loader or backhoe equipment must be securely supported and residual hydraulic pressure released before service. Refrigerant work requires recovery equipment, and heavy assemblies require correctly rated lifting gear.