Komatsu D61EX-12, D61PX-12 Bulldozer Shop Manual (P/N SEBM018904)

• Covers Komatsu D61EX-12 and D61PX-12 crawler tractors, serial 1001 and up and B1001 and up. Serial-specific chapters distinguish machines 1001–1173 / B1001–B3000 from B3001 and up and identify the related S6D114E-1A and SA6D114E-2 engine installations.
• Covers removal, installation, disassembly, inspection, and assembly of the PTO, torque converter, Torqflow transmission, transmission control valve, steering brake, HSS unit, HSS motor, final drives, and associated power-train pumps.
• Includes power-train, steering, and work-equipment pressure testing; PPC valve adjustment and output checks; HSS motor leakage testing; hydraulic-cylinder bleeding; control-linkage adjustment; and steering-brake performance checks.
• Details track-frame and recoil-spring service, idler and roller overhaul, lubricated track-shoe rebuilding, one-link field repair, pivot-shaft and equalizer-bar work, hydraulic-cylinder repair, and blade/work-equipment removal and assembly.
• Provides electrical, hydraulic/mechanical, and machine-monitor troubleshooting with connector locations, pin-arrangement views, symptom-based flow diagrams, and serial-specific cab and canopy circuit diagrams.
• This 678-page PDF contains Komatsu shop manual P/N SEBM018904, printed in Japan in December 2002, together with special-tool data, maintenance standards, torque tables, fluid and lubricant specifications, pressure-test data, adjustment specifications, and wear limits.

Serial-Specific Chassis and System Coverage

This is the chassis shop-manual volume for the D61EX-12 and D61PX-12. Its repair coverage centers on the power train, HSS steering and braking systems, undercarriage, work equipment, hydraulic controls, machine monitor, and chassis electrical system. The manual also distinguishes angle-tiltdozer, semi-U dozer, straight-tiltdozer, ripper, cab, ROPS-cab, and canopy arrangements where those configurations affect components, piping, controls, or circuit diagrams.

The serial break matters. Earlier chapters cover machines 1001–1173 and B1001–B3000, while later sections are marked for B3001 and up. The change is reflected in the engine installation, hydraulic/HSS pump material, PPC and main-control-valve layouts, HSS components, and the hydraulic and electrical schematics. That separation helps a technician select the correct system view and repair section before ordering parts or connecting test equipment.

Engine content is deliberately limited by the volume structure. The manual identifies the S6D114E-1A and SA6D114E-2 installations and includes engine removal and installation plus chassis-side checks such as blow-by pressure, exhaust color, oil pressure, speed, belt adjustment, and torque-converter stall testing. It is not a full internal engine-overhaul manual; internal engine rebuilding requires the corresponding engine volume.

Testing, Troubleshooting, and Repair Procedures

The testing and adjusting section supplies standard-value tables for the engine installation, chassis, and electrical system, followed by the tools and measuring points used for diagnosis. Procedures cover power-train hydraulic pressure, work-equipment and steering pressure, control-circuit pressure, PPC output pressure, HSS motor oil leakage, cylinder linkage, and major control adjustments. Fuel-control, forward/reverse, gearshift, parking-brake, brake-pedal, work-equipment lock, straight-tiltdozer, and PPC linkages are addressed as separate checks rather than a single generic adjustment section.

Troubleshooting is divided into three practical groups. E-mode traces starting, lighting, preheating, wiper/washer, air-conditioning, and engine-stop electrical faults. H-mode addresses hydraulic and mechanical symptoms such as weak or delayed steering, brake problems, no-travel conditions, abnormal power-train oil temperature, low drawbar pull, pump noise, slow or weak work equipment, blade drift, and failure to turn. M-mode covers monitor-display, caution-lamp, warning-buzzer, gauge, service-meter, and panel-lighting faults. Connector mounting locations, pin-number tables, pin-arrangement drawings, system schematics, and symptom flow diagrams support those checks.

The disassembly and assembly section goes well beyond component identification. It covers factory repair procedures for the PTO, torque converter, planetary Torqflow transmission, steering brake, HSS unit and motor, final drives, hydraulic/HSS pump, PPC pump and charge-relief components, main control valve, steering PPC valve, suction valve, blade cylinders, and work equipment. Undercarriage work includes recoil-spring removal and assembly, idler and roller overhaul, complete lubricated track-link service, one-link field repair, pivot-shaft work, equalizer-bar bushing replacement, and segment-tooth service.

Dedicated tool drawings and part numbers are included for major shop work. Examples include clutch-piston oil-leak tester 799-301-1600, floating-seal installer 791-545-1510, recoil-spring tooling centered on compressor 791-685-8006, and minimum swash-plate-angle gauge assembly 791-463-1200.

Schematics, Service Data, and Repair Cautions

Useful visual references include the power-train hydraulic circuit, serial-specific steering and work-equipment hydraulic circuits, cab and canopy electrical circuit diagrams, connector mounting and pin-arrangement views, Torqflow transmission sectional and exploded views, and section drawings for the hydraulic/HSS pump and HSS motor. The maintenance-standard chapters pair those drawings with component inspection criteria, wear limits, clearances, torque specifications, approved fluids, capacities, and adjustment data.

Several cautions show why the factory procedures matter. The final-drive and roller sections warn that floating-seal faces and O-ring seats must remain clean, dry, undamaged, and correctly seated; contamination or an inclined seal can cause leakage. During lubricated-track overhaul, poor link-press centering can damage the link bore, break a pin, or crack a bushing, while damage to the bushing end face or seal surface can lead to oil loss. The hydraulic/HSS pump assembly section also flags the risk of damaging the rocker cam and cradle when the piston is tightened without the required support and positioning.

Because this manual covers stored-energy recoil springs, pressurized hydraulic circuits, and suspended power-train and undercarriage assemblies, repair work should be performed only with the machine secured, residual pressure released, and correctly rated lifting and press equipment.