Manual for DIY repairs: Komatsu Shop Manual for Crawler Dozer Models D31EX-21, D31PX-21, D37EX-21, D37PX-21, D39EX-21, D39PX-21 2007

Komatsu D31, D37, D39 Service & Repair Manual - 2007

This professional-grade technical documentation provides factory-sanctioned procedures for the maintenance, diagnostic testing, and overhaul of Komatsu crawler dozers. Utilizing these specialized instructions ensures maximum machine uptime, maintains precise hydraulic performance, and prevents costly component failures through rigorous adherence to maintenance standards.

Model Coverage & Engine Specifications This manual covers both EX (standard) and PX (swamp) configurations for the following 21-series machines, all powered by the Komatsu SAA4D102E-2-B turbocharged, air-cooled aftercooled diesel engine:

• Komatsu D31EX-21 / D31PX-21 (2007): 56 kW {75 HP} @ 2,000 rpm
• Komatsu D37EX-21 / D37PX-21 (2007): 63 kW {85 HP} @ 2,000 rpm
• Komatsu D39EX-21 / D39PX-21 (2007): 71 kW {95 HP} @ 2,200 rpm

Professional Benefits

• Technical Accuracy: Provides exact KES (Komatsu Engineering Standard) torque values and clearance limits to ensure repairs meet original equipment manufacturer specifications.
• Operational Safety: Includes vital safety notices for high-pressure hydraulic handling, battery disconnection procedures, and heavy component slinging (standard JIS G3525).
• Error Prevention: Features verbatim wiring codes and color tables to prevent electrical system damage during troubleshooting or component replacement.

What’s Included in This Service Manual Set:

This technical suite consists of the primary Chassis Shop Manual (SEBM035005) and refers to the 102 Series Engine Shop Manual for internal engine work. The documentation includes deep-dive chapters on Hydrostatic Transmission (HST) systems, Closed-center Load Sensing System (CLSS) hydraulic operations, and the Equipment Management Monitoring System (EMMS).

Technical Identification & Specifications

Serial Number Locations

• Machine Product ID: Located on the ID plate fixed to the front of the main frame or operator's compartment.
• Engine Serial Number: Found on the engine cylinder block nameplate.
• HST Pump/Motor IDs: Individual identification plates are fixed to each unit for specific part tracking.

Technical Highlights

• HST System Pressures: Main circuit relief pressure is 40.2 – 44.1 MPa {410 – 450 kg/cm²} during stall testing; Charge circuit pressure is 3.04 ± 0.29 MPa {31 ± 3.0 kg/cm²}.
• Work Equipment Hydraulics: Standard relief pressure is 20.6 MPa {210 kg/cm²}.
• Critical Torques: Cylinder head bolts require a multi-stage tightening (1st: 90 Nm, 2nd: 120 Nm, 3rd: +90°); Track shoe regular link bolts require 265 ± 30 Nm for D31/D37 and 196 ± 19.6 Nm plus 120° for D39.
• Undercarriage Clearances: Idler guide plate-to-track frame clearance limit is 4.0 mm; standard track tension sag is 20 – 30 mm.

Contents at a Glance

• 01 General: Dimensions, weights, and detailed machine specifications.
• 10 Structure and Function, Maintenance Standard: Component deep-dives including HST hydraulic arrangement, final drives, and CLSS control valve logic.
• 20 Testing and Adjusting: Standard value tables, engine performance tests, and EMMS special functions.
• 30 Disassembly and Assembly: Removal/installation steps for the HST pump, engine assembly (650 kg), and hydraulic cylinders.
• 90 Others: Full-scale hydraulic and electrical circuit diagrams for system-wide diagnostics.

Professional Value

Enables field-level calibration of the Hydrostatic Transmission (HST) through the monitor panel (EMMS) "Adjustment Mode" (Codes 3001-3006). This allows technicians to synchronize pump delivery and motor speed sensors without the immediate need for external proprietary dealer software, facilitating precise travel deviation corrections and stall pressure checks on-site.