Electrical faults are the hardest calls on these machines, and the 782-page Komatsu PC400-7 shop manual PDF (OEM ID SEBM033007) gives them more room than any other chapter, tracing S-NET communication, engine controller and solenoid valve failures across four variants of the PC400-7 and PC450-7 hydraulic excavator family, standard and LC. Beyond that E mode section, the H mode and S mode charts trace hydraulic drift, slow swing, weak travel speed, overheating and hard starting back to a cause, and the disassembly chapter takes you through the cylinder head, swing motor and final drive. Wiring diagrams at the back show the full electrical circuit routing. Check No. 1 sun gear to planetary gear backlash at 0.15 to 0.54 mm, and torque 10 mm metric bolts to 59 to 74 Nm. Out on a remote site, there is nobody to call. Bookmarked chapters and a searchable text layer take you straight to the fix and get your excavator running under load again.
What's Inside This Manual
| System | Pages | Key Topics |
|---|
| General | 28-39 | Specification Drawings, Specifications, Weight Table |
| Structure, Function and Maintenance Standard | 40-238 | Hydraulic Pump, Control Valve, Swing Motor |
| Engine Testing and Adjusting | 239-289 | Engine Speed, Intake Air Pressure, Exhaust Gas Temperature, Valve Clearance, Compression Pressure, Engine Oil Pressure |
| Chassis Testing and Adjusting | 290-354 | Swing Brake Angle, Travel Speed, Hydraulic Drift, Work Equipment Speed, Internal Leakage, Compound Operation Performance |
| Troubleshooting - Electrical System (E Mode) | 355-565 | Monitor Panel, Windshield Wiper, Engine Controller, S-NET Communication, Solenoid Valves, Air Conditioner System |
| Troubleshooting - Hydraulic and Mechanical System (H Mode) | 566-621 | Work Equipment Power, Swing Speed, Travel Speed, Hydraulic Drift, Abnormal Noise, Compound Operation |
| Troubleshooting - Engine (S Mode) | 622-644 | Starting Performance, Engine Stalling, Exhaust Smoke, Oil Consumption, Overheating, Abnormal Noise |
| Disassembly and Assembly | 645-771 | Removal and Installation of Cylinder Head Assembly, Disassembly and Assembly of Swing Motor and Swing Machinery Assembly, Disassembly and Assembly of Final Drive Assembly |
| Others | 772-782 | Hydraulic Circuit Diagram, Electrical Circuit Diagram |
Quick Reference Specifications
| Specification | Value | Page |
|---|
| Standard tightening torque for metric bolts (6mm) | 11.8 – 14.7 Nm | p. 662 |
| Standard tightening torque for metric bolts (8mm) | 27 – 34 Nm | p. 17 |
| Tightening torque for flared nuts (14mm) | 24.5 ± 4.9 Nm | p. 17 |
| Tightening torque for flared nuts (18mm) | 49 ± 19.6 Nm | p. 17 |
| Backlash between No. 1 sun gear and No. 1 planetary gear | 0.15-0.54 mm | p. 45 |
| Backlash between No. 1 planetary gear and ring gear | 0.18-0.66 mm | p. 45 |
| Backlash between swing motor shaft and No. 1 sun gear | 0.18-0.28 mm | p. 49 |
| Backlash between No. 1 planetary carrier and No. 2 sun gear | 0.40-0.75 mm | p. 49 |
| Hydraulic pump assembly tightening torque (Front pump pressure input) | 11.8-14.7 Nm | p. 662 |
| Hydraulic pump assembly tightening torque (Rear pump delivery pressure detection) | 11.8-14.7 Nm | p. 662 |
| Spool return spring (No. 11) Installed load | 416.5 N {42.5 kg} | p. 91 |
| Spool return spring (No. 11) Repair limit installed load | 333.2 N {34 kg} | p. 91 |
