Description

Komatsu D51EXi-22, D51PXi-22 2014 Service Manual – 1574 Pages of Factory Specs

After 28 years in this trade, I have seen more back-of-the-napkin torque values than I care to count. Guys guess at head bolt specs on a $300,000 dozer because the aftermarket manual they bought skipped the critical tables. That ends here. This is the Komatsu D51EXi-22, D51PXi-22 2014 Service Manual — the exact document Komatsu dealerships use. 1574 pages, no reprints, no condenser. If you are working on a D51EXi-22 or D51PXi-22 with serial numbers B13500 and up, this is your only source for verified factory data. Want the standard tightening torque for a M20 bolt? Page 0-50. Need to know how to handle the high-pressure fuel system on the 6D107E-1 engine? Page 0-27. That is the difference between a repair that holds up and a comeback that costs you a week.

Handling Equipment of Fuel System Devices

Fuel system work on these dozers is not something you guess at. The manual opens with a dedicated section on handling equipment of fuel system devices (page 0-27). It covers the proper procedure for bleeding, injector removal, and high-pressure line torque. The 6D107E-1 uses common-rail injection — one mistake with a crush washer and you are looking at a fuel leak that can start a fire. The manual tells you exactly which wrenches are required and how to avoid contamination. This is not a suggestion; it is the procedure that the engineers who designed the engine wrote.

Does This Manual Cover the Electrical System?

It does. The Electrical System section in chapter 10 runs through the monitor system, engine control system, HST control, gear shift control, parking brake control, KOMTRAX, and the ICT control system. You get wire codes, sensor locations, and diagnostic procedures for every sensor listed in the table of contents — brake oil pressure sensor, hydraulic oil temp sensor, fuel level sensor, coolant temp sensor, WIF sensor, IMU sensor, and the stroke/reset sensors for lift, tilt, and angle cylinders. If you have an electrical gremlin, the wiring diagrams and pin-out tables are inside. Most aftermarket manuals skip half these sensors. This one has them all.

3 Major Systems Detailed in the Structure and Function Chapter

Chapter 10 is not a quick overview. It breaks down the machine into three major systems: Engine and Cooling System (cooling fan pump, oil cooler bypass valve, charge safety valve), Power Train (HST closed circuit, damper, HST pump, motor control valve, final drive), and Hydraulic System (work equipment control, servo valve, control valve, unload valve, pressure compensation valve, accumulator). Each component gets its own sub-section with cross-section drawings, flow diagrams, and failure analysis. You want to know why the blade assist control is lagging? The ICT control function chapter explains the dozing modes, smooth start, slip control, and blade assist logic. That is the kind of depth you only get from an OEM factory manual.

Get the Right Torque Data from the Foreword

The foreword section contains the standard tightening torque table (page 0-50) for metric bolts used throughout the machine. It also has the conversion table and list of abbreviations. Before you torque a single fastener, look up the grade and pitch in that table. The manual also specifies tightening sequences for the HST pump mounting bolts and the final drive ring gear. Use a calibrated torque wrench — inch-pounds for small sensors, foot-pounds for structural bolts. Anything less is a failure waiting to tear a gearbox apart.

HST Control System: Factory Diagnostics

The hydrostatic transmission on these models is a closed-loop system with a charge pump, safety-suction valve, towing valve, and EPC valves. The manual gives you a performance measuring posture and method in section 20, including tools for testing and adjusting. It lists engine speed, intake boost pressure, exhaust temperature, valve clearance, compression pressure, and blow-by pressure. You will find standard value tables for the engine, chassis, and ICT. If the HST motor is not responding, you trace the solenoid valve (3-spool) and the EPC valve (2-spool) with the specific electrical resistances listed in the manual. No guesswork.

Replacing a hydraulic component? The Handling of Hydraulic Equipment section explains the push-pull type coupler disconnect procedure and how to avoid air entrapment. Aftermarket manuals often tell you to “bleed the system” without specifying the exact sequence. This one does.

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Frequently Asked Questions

Is this the official Komatsu factory manual?

Yes. This is the exact PDF used in Komatsu dealerships.

Why should I choose this over a $30 aftermarket manual?

Aftermarket manuals often summarize or omit critical data like the charge safety valve specs, the standard torque table, and the ICT controller troubleshooting flowcharts. They also lack the original color wiring diagrams and the handling procedures for fuel system devices. This 1574-page OEM manual includes every page from the factory binder — including the warnings about high-pressure hydraulic fluid injection injuries. When you are bleeding the fuel system on a 6D107E-1 engine, the aftermarket manual might say “loosen the bleeder screw.” This manual tells you which screw, what torque to retighten it, and what to do if the engine won’t restart. That difference can save you an injector replacement or a hydraulic pump failure. I have seen techs waste four hours chasing a wiring fault that the aftermarket diagram mislabeled. The OEM schematic is color-coded and verified by Komatsu. Spend the money on the factory manual once; it pays for itself on the first repair.

If you are serious about keeping a D51EXi-22 or D51PXi-22 running at production spec, you need the real thing. Aftermarket garbage will cost you more in comebacks and wasted time than this manual ever will. Access the Factory Manual today and get the complete 1574-page document with all torque tables, wiring diagrams, and step-by-step procedures.