Description

Komatsu WA90-5, WA100M-5 2005 Workshop Manual

If you have ever cracked open a hydraulic line on a WA90-5 without knowing the charge pressure spec, you know the feeling. That oily mix of regret and guesswork. This 2005 workshop manual from Komatsu is the factory document that puts a stop to that. 301 pages of what you actually need: torque values for every fastener on the machine, the exact sequence for bleeding the hydrostatic drive, and the valve lash clearance for the S4D95LE-3 engine. No reprints, no third-party summaries – just the original OEM binder dumped into a PDF. The Komatsu WA90-5, WA100M-5 2005 Workshop Manual is what I pull up on the tablet when a loader comes in with a steering pressure complaint.

This manual covers both WA90-5 and WA100M-5 models from serial number 50051 and up. You get the same content that Komatsu sent to dealers: the torque list for screws and nuts, the foldout wiring diagrams, and the standard value tables for engine and chassis. Need the engine RPM specs? Page 73 of the PDF – but you already know that because the table of contents is bookmarked. Let us get into what matters.

Safety First: Why This Section Matters

Page 00-1 starts with a safety notice that covers tipping up the driver’s cab – both standard and electric actuator options. If you have ever tried to flip a cab without knowing the lock positions, you understand why Komatsu put this at the front. The manual walks through preparations for work, precautions during work, and hydraulic system safety. Wire rope hoisting instructions are included. Skip this section and you risk pinching a line or dropping a cab. The manual makes no assumptions about your experience.

General Section: Specs, Torque List, and Maintenance

Section 01 gives you dimensions, weights, and operating data for both models. WA90-5 weighs in at a certain curb weight – check page 01-3 for the exact number. There is a separate weight table for WA100M-5. Lubricants and operating mediums: the manual lists the correct oil, fuel, coolant, and grease. It even covers biodegradable hydraulic oils and filters. Then you hit the torque list – the single most referenced table in a real shop. That list gives you tightening torques for screws and nuts in Nm (but you can convert to ft-lb if you must). This is the same spec you would get from a Komatsu dealer hotline. No guessing.

Structure and Function: Steering, Hydraulics, Axles

Section 10 is where the manual earns its keep. The hydraulic circuit diagram of the steering system is shown. Then the hydrostatic drive: closed circuit, variable displacement pump with regulating valve, charge pressure limiting valve, control cylinder, and the 4/3 way solenoid valve. The manual explains the 20 km/h and 30 km/h drive system. Front axle with inner disc brake as service brake and outer disc brake as parking brake. Rear axle with transfer box TB172. Limited slip differential locking value 25% – the manual tells you how it works and what to check when it fails. Service and parking brake circuit diagrams are there. The steering articulation joint with priority valve and orbit-roll valve. Work equipment hydraulics: PPC valve, servo pressure regulating valve, emergency lowering system. If you are inside a main control valve, you need this.

H2: Testing and Adjusting: The Standard Value Tables

Section 20 is the diagnostic backbone. Standard value tables for engine (both models) and chassis (separate for WA90-5 and WA100M-5). Electrical parts standard values. Test certificates for both models. Valve lash clearance, engine compression test, injection nozzle pressure, fuel injection timing, V-belt tension, engine RPM, RPM-dependent drive take-up, engine stall torque RPM tests – including with hydrostatic drive and with working hydraulics. Feed pump and servo oil pressure, hydraulic pressure cut-off, working hydraulic pressure. You also get steering oil pressure testing and steering neutral zone testing. Page 73 as I said. This is the section that saves you from replacing a pump that is actually fine but has a bad charge relief valve.

H2: Wiring Diagrams and Electrical Diagnostics

The manual includes five foldout wiring diagrams (1/5 through 5/5) plus speed control and immobilizer. Those are printed as foldouts in the paper manual; the PDF preserves them as full-page spreads. Engine start/preheating circuit, fuses and relays with locations in the engine room. Sensors: engine oil pressure, fuel level, coolant temperature, brake oil reservoir. Ribbon heater. Air conditioner option with full troubleshooting. If you have an electrical gremlin on a WA100M-5, start with the wiring diagram 3/5 – it covers the PPC valve control.

H2: Does This Manual Cover Both WA90-5 and WA100M-5?

Yes. The manual explicitly lists dimensions, specifications, and weight tables for each. The testing section has separate standard value tables for chassis – WA90-5 and WA100M-5. Lift cylinder and dump cylinder specs are different between models – the manual gives separate pages for each. The torque list applies to both. Komatsu WA90-5 2006 Operators Manual – 257 Pages OEM covers the operator-side info, but for repairs you need this shop manual. Komatsu WA90-5 Operators Manual – Factory Specs & Safety is a good companion if you want the daily pre-start checklist. Komatsu WA65-5 WA70-5 WA80-5 2005 Workshop Manual covers the smaller frame loaders if that is your fleet. For external reference on how a Manual Transmission works in general, you can look up the basics elsewhere – but this manual specifically deals with the hydrostatic drivetrain, not a manual gearbox. The same goes for understanding Manual Transmission concepts – not relevant here, but worth knowing if you are cross-training.

What is the difference between the WA90-5 and WA100M-5 in this manual?

The manual treats them as separate machines with their own dimensions, weights, lift and dump cylinder specs, and chassis standard value tables. The powertrain and hydraulic system are largely shared.

Does the manual include the engine manual?

The S4D95LE-3 engine is covered in a separate Cummins bulletin number 3666418-00. This shop manual covers engine testing (valve lash, compression, injection nozzle pressure) but not full engine overhaul. For that, get the engine manual.

Are the wiring diagrams readable in the PDF?

Yes. The PDF includes five foldout wiring diagrams plus speed control and immobilizer diagrams. They are high-resolution scans. You may need to zoom, but every wire label is legible.

What torque values are listed?

The torque list in section 01 covers screws and nuts for the whole machine – from axle mounting bolts to hydraulic line fittings. The manual does not give a generic “tighten to spec” – it gives specific Nm values for each size and grade.

This is the document you need on the workbench when the loader is down and the customer is waiting. The OEM torque spec is the only one that matters. Access the Factory Manual now.