1978 Komatsu D40A-1, D40P-1, D45A-1, D45P-1, D45S-1 Bulldozer & Dozer Shovel Shop Manual

This 1978 Komatsu shop manual, cover reference D40,45.1-BE2, covers the D40A-1, D40P-1, D45A-1 and D45P-1 bulldozers and the D45S-1 dozer shovel, with S4D105-1 and S4D105-3 engine data.

• Engine repair: Cylinder-head, piston, liner and crankshaft work, timing-gear assembly, lubrication-system service, water-pump overhaul, compression testing and maintenance standards.

• Fuel injection: Injection-pump and RSV governor disassembly, reassembly and test-stand adjustment, plus nozzle testing, injection timing and fuel-system bleeding.

• Power train: D40 main-clutch and sliding-gear transmission service; D45 torque-converter, planetary transmission and transmission-control-valve repair.

• Steering and undercarriage: Steering-clutch and brake adjustment, final-drive work, track-frame alignment, roller and idler servicing, and sprocket wheel segment replacement.

• Hydraulic control: Blade and D45S bucket circuits, control-valve and cylinder service, pressure and flow testing, and troubleshooting for slow lifting and excessive blade drift.

• Electrical system: Model-specific wiring diagrams, starting and charging diagnostic charts, starter and alternator overhaul, and safety-relay testing.

This manual suits experienced heavy-equipment mechanics with lifting and precision-measuring equipment; injection-pump calibration also requires a suitable test stand.

Engine Inspection and Fuel-System Repair

The engine chapters separate work performed with the engine installed from procedures requiring engine removal. Repair instructions extend to valve seats, nozzle-holder sleeves and crankshaft journals, with inspection limits and component-specific tightening data.

Turbocharger coverage includes removal and installation, rotor inspection, and radial- and end-play measurement. Injection-pump adjustment is documented around the DIESEL KIKI 5760-050 test stand, with the required measuring fixtures identified.

The fuel-system cautions explain why increasing injection-pump delivery to compensate for a power-loss fault elsewhere can damage the engine.

General assembly drawings, engine general views, engine assembly drawings and performance curves support component identification. Weight tables and oil and water capacity charts provide additional workshop reference data.

D40 and D45 Drivetrain Differences

D45 damper, torque-converter and hydraulic-control drawings distinguish the versions before and from serial number 1801. D40 hydraulic clutch-booster illustrations distinguish the versions before and from serial number 2201. These distinctions help match the machine to the appropriate assemblies and test information before parts are selected.

Troubleshooting tables address weak tractive effort, clutch slip, delayed engagement and harsh shifting. Steering-case procedures include bevel-gear bearing preload, backlash and tooth-contact adjustment.

Track Wear, Rollers and Seals

Track-link pitch and bushing-wear criteria help determine whether pins and bushings can be turned for further service or require replacement. Track-frame, roller and idler alignment checks complement those wear measurements.

Track tension adjustment and track roller, carrier roller and idler oil changes are documented, including nozzle assembly 141-98-15440 for roller servicing. Floating-seal instructions explain how incorrectly seated or twisted O-rings can be damaged and cause oil leakage.

Follow the manual's lifting, machine-support and hydraulic-pressure precautions before working on the chassis or attachments.

Blade Hydraulics, Bucket Controls and Pump Coverage

Separate hydraulic circuit diagrams cover the bulldozer attachments and D45S lift and dump functions. Pressure and flow tests, relief-valve checks and blade-drift diagnosis help distinguish pump delivery problems from internal cylinder or control-valve leakage.

The gear-pump chapter contains detailed PAR056 work-attachment pump procedures and FAR020/FAR028 steering and TORQFLOW pump service. Its identification chart also distinguishes PAL071 and later KAR3-056/KAR3-071 attachment-pump installations; the detailed attachment-pump teardown section is labeled PAR056.

D40 tandem-pump scope: FAL020+020 coverage includes removal and installation, oil-seal replacement and performance testing. The service instructions limit internal disassembly to the specified oil seal and call for pump-assembly replacement when performance falls below the stated limits.

Starting and Charging Diagnosis

Separate D40A/P, D45A/P and D45S wiring diagrams are supported by instrument-panel wiring layouts and switch-connection tables. Diagnostic flowcharts connect starting, charging, preheater, lighting and horn symptoms with terminal checks and component diagnosis.

Starter, alternator, regulator and safety-relay inspection data provide the corresponding electrical and mechanical test criteria.

Examples of Lubrication and Cooling Data

These two entries are a small sample of the technical data included in the manual.

The engine oil-pump regulator has a specified cracking pressure of 3.9–4.4 kg/cm². This describes the regulator's opening threshold, rather than a general running oil-pressure specification.

For the D45S-1, the capacity table lists approximately 35 liters of engine cooling water for filling an empty system.

PDF Navigation, Diagram Detail and Page Count

Search and wiring detail: PDF text search and embedded bookmarks are unavailable. Small wiring labels require enlargement. Parts of the D45S electrical circuit remain faint or incomplete even when enlarged; this affects the diagram on PDF p. 336.

Supplied as one printable, 966-page PDF. The total already includes the original cover, 13 section cover sheets, 23 blank pages and 15 memo pages.