Only Komatsu can settle what a healthy machine should read on the gauge, and this 473-page Komatsu PC20R-8, PC25R-8, PC27R-8 shop manual PDF (SEBM010801) puts those factory standard values in writing for all three hydraulic excavators. Testing and adjusting fills a large share of the book: standard value tables for engine, chassis and electrical, plus troubleshooting charts that trace a fault to its source. Hydraulic circuit diagrams follow the CLSS piping from pump to control valve, wiring diagrams cover the electrical side, and the longest section takes you through rebuilding the fuel injection pump and hydraulic cylinders. On the PC25R-8 and PC27R-8, refill the hydraulic system with 29 L after a service (50 L specified; the PC20R-8 takes 25 L of 40 L) and torque the swing motor safety valve locknut to 90.65 ± 12.25 Nm. Tracing a sluggish circuit on a machine this compact is cramped work. Bookmarked and text-searchable, the PDF rides on your laptop or phone, so it sits wherever the excavator is parked.
What's Inside This Manual
| System | Pages | Key Topics |
|---|
| General | 1-41 | Safety Notice, Hoisting Instructions, Coating Materials |
| Structure and Function | 42-138 | Power Train, Hydraulic Piping, Hydraulic Pump, Control Valve |
| Testing and Adjusting | 139-261 | Standard Value Table for Engine, Standard Value Table for Chassis, Standard Value Table for Electrical |
| Disassembly and Assembly | 262-431 | Starting Motor, Fuel Injection Pump, Hydraulic Cylinder |
| Maintenance Standard | 432-464 | Swing Circle, Track Roller, Work Equipment |
| Others | 465-473 | Hydraulic Piping, Hydraulic Circuit Diagram, CLSS Operation |
Quick Reference Specifications
| Specification | Value | Page |
|---|
| Standard tightening torque for metric nuts and bolts (6 mm) | 13.2 ± 1.4 Nm | p. 14 |
| Standard tightening torque for metric nuts and bolts (8 mm) | 31 ± 3 Nm | p. 12 |
| Hydraulic system oil refill capacity | 29 L | p. 40 |
| Hydraulic system oil specified capacity | 50 L | p. 40 |
| Swing motor safety valve locknut torque | 90.65 ± 12.25 Nm | p. 173 |
| PC20R work equipment relief pressure | 17.2 +0.49/0 MPa (175 +5/0 kg/cm²) | p. 230 |
| PC20R arm IN relief pressure | 17.2 +0.49/0 MPa (175 +5/0 kg/cm²) | p. 233 |
| PC25R work equipment relief pressure | 19.6 +0.49/0 MPa (200 +5/0 kg/cm²) | p. 230 |
| PC25R arm IN relief pressure | 19.6 +0.49/0 MPa (200 +5/0 kg/cm²) | p. 233 |
| PC27R work equipment relief pressure | 20.6 +0.49/0 MPa (210 +5/0 kg/cm²) | p. 230 |
| PC27R arm IN relief pressure | 20.6 +0.49/0 MPa (210 +5/0 kg/cm²) | p. 233 |
| Engine Oil Capacity (Specified) | 3.4L | p. 40 |
