Komatsu WB91R-2 / WB93R-2 Backhoe Loader Shop Manual (P/N WEBM000404)

Komatsu Utility shop manual P/N WEBM000404 covers WB91R-2 and WB93R-2 Avance backhoe loaders, starting at serial numbers 91F20145 and 93F23453, respectively.

PDF Search, Bookmarks and Wiring Detail

Finding text and diagram details: Text search is available across the main technical sections, with embedded bookmarks for component navigation. Most cover lettering is not searchable; small wiring labels require zooming.

One printable PDF contains 504 pages. This total includes the cover, two revision-list pages, four section dividers, 22 blank or near-blank pages, and the 14-page control valve repair insert.

Drivetrain Overhaul and Load-Sensing Hydraulic Diagnosis

These selected workshop topics give a snapshot of the manual; further subjects include engine-speed checks under load and brake-pedal/microswitch adjustment.

• Engine testing and component service: Compression testing, injection timing and valve-clearance adjustment, plus cylinder-head, injection-pump and turbocompressor removal and installation.

• Transmission overhaul: Step-by-step disassembly and reassembly, clutch-pack service, synchronizer inspection, converter checks, and forward/reverse clutch pressure testing.

• Axles and brakes: Front and rear axle overhaul, planetary reduction gears, differential setup, pinion-bearing preload, and brake-system testing and bleeding.

• Hydraulic diagnosis: Variable-flow pump and CLSS operation, LS and unloading-valve tests, hydraulic drift diagnosis, and serial-specific control valve repair.

• Working equipment: Boom, arm, bucket, outrigger and swing-cylinder service, telescopic/jig arm work, and return-to-dig sensor adjustment.

• Electrical systems: Machine wiring diagrams, connector identification, wire-color and thickness tables, and starter-motor and alternator removal and installation.

• Air conditioning: R134a system diagrams, operating pressure and temperature diagnosis, refrigerant evacuation, and compressor and condenser removal and installation.

Suited to workshop mechanics familiar with heavy-equipment service, with access to lifting equipment, pressure gauges and the specified assembly tools.

Engine and Cooling-System Work

Cylinder-head coverage includes removal, installation and fastening details. Cooling-system procedures address the thermostat, water pump and radiator.

Repair scope: Engine coverage centers on testing, adjustments and component removal/installation; it does not provide a complete internal engine overhaul. The injection pump, turbocompressor and steering unit have removal/installation procedures rather than internal rebuilding chapters.

Transmission and Axle Bench Repairs

The transmission overhaul chapter follows the input, secondary, main and reverse shafts, including clutch-pack checks, synchronizer inspection and distributor reassembly. Its hydraulic converter-transmission circuit diagram connects these assemblies with converter and clutch pressure testing.

Axle setup: Exploded drawings and section views support bevel-gear contact, backlash and bearing-preload checks. The tool tables identify false pinion CA715023 for the front axle and CA715128 for the rear axle.

The axle procedures warn that excessive pinion-nut tightening over-compresses the elastic spacer, requiring its replacement.

Inspection references: Maintenance-standard tables provide component dimensions, clearances and wear criteria for evaluating dismantled parts. Torque specifications cover standard bolts, nuts and flared fittings; fluid tables distinguish total-fill and refill quantities and relate oil viscosity to ambient temperature.

CLSS, Control Valves and Hydraulic Cylinders

The hydraulic circuit and PC valve/LS valve/servo-piston views explain delivery control and load compensation. Hydraulic-drift tests help distinguish cylinder-seal leakage from leakage through a control valve before components are removed.

Valve repair applicability: The inserted repair section applies to WB91R-2 from s/n 91F20169 and WB93R-2 from s/n 93F24324, including 93F24234–93F24237, 93F24299 and 93F24301.

That section covers flow regulators, spool seals, detents and individual pressure compensators, with symptom/cause/check/remedy charts for the SX14 control block. Its seal precautions explain how contact with spool grooves can damage the lip seal and reduce sealing.

Cylinder assembly: Drawings distinguish seal arrangements for the boom, outriggers, telescopic/jig arm and side-digging boom cylinders. Related inspection tables cover working-equipment pins, bushings and swing-bracket components.

Follow the manual’s support, locking and pressure-release precautions when working around raised loader or backhoe equipment.

Electrical Tracing and A/C Fault Diagnosis

The machine wiring sheets and separate air-conditioning electrical diagram include component and connector keys. Wire-color and cross-section tables support harness tracing.

The R134a diagnostic chart compares high- and low-side pressure patterns to distinguish possible compressor, expansion-valve and moisture-filter faults.

Sample Valve-Clearance and Solenoid Test Data

The engine tables specify standard intake and exhaust valve clearance of 0.30 ± 0.05 mm at 20°C for both the 4D106-1FA and S4D106-1FA engines, alongside the valve-adjustment procedure.

For the SX14 control block in the serial-specific repair section, the slow-movement troubleshooting chart lists 2.5 Ω at 25°C for direct electrical spool-control solenoids.