A travel motor weeping oil behind the sprocket, or a swing that drifts after you center the lever: that is the job waiting on your K903-II. The Kobelco K903-II shop manual PDF (S5LE0004E-01 NA) answers it in 554 pages written for this hydraulic excavator. Hydraulic circuit diagrams trace the bucket, arm, boom, travel and swing preferential circuits, wiring diagrams lay out the engine and pilot control systems, and troubleshooting charts sort faults by drive, hydraulic and swing system. Roughly half the book goes to component overhaul: pump, swing control valve, both hydraulic motors, swivel joint and cylinders. Check bucket port relief against the 190 to 230 kgf/cm² (2,702 to 3,271 psi) window, then torque 15x2.0 tube fittings to 15 ± 2 kgf-m (108 ft-lbs). Out here it's you, the machine, nobody to ask. Bookmarked by section and text-searchable, this file is yours once bought, kept for this K903-II as long as it runs.
What's Inside This Manual
| System | Pages | Key Topics |
|---|
| Specification | 8-25 | General Dimensions, Specifications and Performance, Working Range of Attachments |
| Location and Weight of Components | 26-33 | Location of Components, Weight of Components, Transportation Weight |
| Maintenance Standards and Test Procedures | 34-63 | Hydraulic Pressure, Cylinder Speed, Cylinder Oil-Tightness |
| Troubleshooting | 64-85 | Drive System, Hydraulic System, Swing System |
| Working Standards | 86-89 | Tightening Torques for Capscrews, Tightening Torques for Nuts and Sleeves |
| Systems - Drive System | 90-105 | Power Plant, Pump Connection, Removal and Installation of Hydraulic Pump, Removal and Installation of Coupling, Removal and Installation of Engine |
| Systems - Hydraulic System | 106-143 | Hydraulic Circuit Diagram, Functional Description of Hydraulic Circuits, Bucket Circuit, Arm Circuit, Boom Circuit, Travel Circuit, Swing Preferential Circuit |
| Systems - Swing System | 144-165 | Swing System Drive Piping, Swing Grease Bath, Removal and Installation of Swing Control Valve, Removal and Installation of Swing Motor |
| Systems - Travel System | 166-221 | Construction of Lower Machinery, Track Link, Upper Roller, Lower Roller, Idler and Track Spring, Removal and Installation of Travel Motor, Removal and Installation of Sprocket |
| Systems - Attachments | 222-251 | Attachment System and Function, Backhoe Attachments, Removal and Installation of Attachments, Clearance Between Pin and Bushing, Adjusting Clearance Between Bucket and Arm |
| Systems - Control System | 252-285 | Engine Control System, Travel Control System, Hydraulic Control System, Pilot Valve, Flow Divider Valve |
| Components | 286-287 | Hydraulic Pump |
| Hydraulic Pump | 288-319 | |
| Swing Control Valve | 320-351 | |
| Control Valve | 352-457 | Pilot Valve, Hydraulic Motor (Swing) |
| Hydraulic Motor | 458-499 | Hydraulic Motor (Travel), Construction and Function, Disassembly and Assembly, Maintenance Standards, Troubleshooting |
| Swivel Joint | 500-511 | |
| Hydraulic Cylinder | 512-535 | |
| Reduction Unit | 536-554 | Reduction Unit (Swing), Major Specifications, Construction and Function, Disassembly and Assembly |
Quick Reference Specifications
| Specification | Value | Page |
|---|
| Filter, return (20) filtration rating | 20 μm | p. 110 |
| Port relief valve for bucket pressure | 190 kgf/cm² (2,702 psi) to 230 kgf/cm² (3,271 psi) | p. 39 |
| Tightening torque for 10x1.5 tube size | 6 ± 1 kgf-m (43.3 ± 7.2 ft-lbs) | p. 89 |
| Tightening torque for 15x2.0 tube size | 15 ± 2 kgf-m (108 ± 14.4 ft-lbs) | p. 89 |
| Displacement capacity | 37.3cc/rev. x 2 (0.0098gal/rev x 2) | p. 290 |
| Rated pressure | 200kg/cm² (2844 psi) | p. 290 |
| Clearance between piston rod and rod bushing | 0.25mm (0.009in) | p. 530 |
| Limit of bend for the piston rod | 1mm/1m (0.039in/3ft3in) | p. 530 |
| Travel speed | 3.9 km/hr (2.48 MPH) | p. 12 |
| Engine rated output power | 55 PS/2200 r.p.m | p. 12 |
| Fully equipped weight | 6,600 kg (14,550 lbs) | p. 29 |
| Engine oil volume (Upper Roller) | 50 c.c. (0.113 gal) | p. 175 |
