Description

Komatsu GD825A-2 2011 Workshop Manual

Trying to get a Komatsu GD825A-2 2011 Workshop Manual grader back to spec without the factory documentation is a sure way to waste hours and break things. I’ve seen techs guess on valve clearance and burn a piston. Don’t be that guy. This is the 926-page binder that came off the line with the machine – Komatsu’s own print, not some third-party cut-and-paste job. It covers the S6D140-1 and S6D140E-2 engines, the Hydroshift transmission, the steering circuit, every brake line, and the CLSS hydraulic system. You want torque values? They’re in section 20. You want hydraulic circuit diagrams? Section 10. You want to pull the transmission without pulling your hair out? Start at page 30-1.

01 General – The First Thing You Need

Section 01 starts with dimension drawings, weight tables, and the critical Fuel, coolant, and lubricants specs. If you’re putting the wrong oil in the transmission – page 01-1 has the factory fill chart. That page alone pays for the manual. Don’t trust the internet; trust Komatsu’s printed spec. The manual also lists the fuel injection timing values and the compression pressure limits right there in the standard value tables. I’ve seen guys run 20-weight where 30-weight belongs because they skimmed a forum. Don’t.

Structure and Function: Hydroshift Transmission and Steering

Section 10 is where the real meat lives. The Hydroshift transmission and transfer piping, the Transmission control valve, the inching control, the drive shaft, and the tandem drive are all broken down with exploded views and hydraulic circuit diagrams. You get the steering circuit system, the double relief valve, the emergency steering system – everything. If you’ve ever scratched your head over the “automatic drain valve” in the brake air piping, this manual gives you the flow path and the test pressures. The Valve bodies are drawn with port numbers. No ambiguous “connect to this” nonsense.

Testing and Adjusting: Valve Clearance and Fuel Timing

Section 20 starts with a standard value table for engine and chassis (page 20-1). Then it walks you through the valve clearance adjustment procedure step by step – with the tool list in the same section. Measuring compression pressure, testing and adjusting fuel injection timing, measuring blow-by pressure, and adjusting belt tension – all there. The troubleshooting charts are laid out by symptom: “S-1 Starting performance is poor” routes you through electrical checks, fuel system checks, and compression tests. No guesswork. If you need to charge the blade accumulator with gas, the procedure is right there under “Charging Blade Accumulator with Gas”. I’ve used that one myself on a 2011 job site.

7 Systems Covered – What You Get in the Binder

This Komatsu GD825A-2 workshop manual covers the full power train (Hydroshift transmission, transfer, final drive, tandem drive), the steering system (including emergency steering), the brake air circuit (air drier, governor, safety valve, spring cylinder), the hydraulic control (CLSS, priority flow divider, blade lift speed adjustment), the electrical system (EVMS, ECU, connector pin tables), the frame and blade attachments (drawbar, ripper, circle rotation gear), and the air conditioner. That’s seven major systems with OEM wiring diagrams and hydraulic schematics that are actually readable – not scanned JPEGs from 1985.

OEM Factory Print vs. Aftermarket

I’ll say it straight: aftermarket manuals are a liability. They re-draw the circuits, approximate the torque values, and leave out the updates. This is the 2011 Komatsu factory print – the same book the dealer techs use. The revision marks are in the front (page 00-2), so you know exactly which pages were updated. No reprint, no copy. It’s the original PDF from Komatsu’s own server. If you’re serious about keeping the machine running, you don’t save $30 on a third-party book and then spend $300 fixing a mis-torqued axle nut.

FAQ

Does this manual cover the S6D140-2 engine?

Yes – it covers both the S6D140-1 and S6D140E-2 engines.

How are the troubleshooting charts organized?

The troubleshooting section (section 20) uses a sequence-of-events approach with connector pin tables, T-branch box locations, and symptom-specific charts (e.g., S-1 for starting, S-2 for low power). Each symptom routes you through electrical checks, pressure tests, and mechanical inspections. There’s a separate chart for the transmission control system, the steering system, and the blade hydraulic system. You don’t flip randomly – you follow the flowchart. I’ve walked through the “inching pedal travel” troubleshooting twice this year and both times the answer was in the chart, not in a YouTube comment.

This is the manual your shop should have had in the drawer six months ago. 926 pages of Komatsu’s own specs, torque tables, wiring diagrams, and step-by-step rebuild procedures. If you work on these graders for a living – or you own one and want to keep the repair costs down – you need this file open on your tablet while you’re under the machine. Access the Factory Manual now and save yourself the expensive lesson.

Related manuals you might need: Komatsu GD825A-2 2008 Training Manual, Komatsu GD825A-2 2008 Workshop Manual – 894 Pages Factory Specs, Komatsu GD825A-2 2004 Service Manual – OEM Motor Grader Guide. For a basic primer on Manual Transmission theory, check this external resource. And if you need the transmission rebuild sequence for other models, the same Manual Transmission fundamentals apply.