Part of the Kubota Repair Manuals.
This is the Kubota Service Manual for the U20-3α, U25-3α, and U25S compact excavators, all built around the D1105 diesel engine. It is the 478 page factory workshop manual, Kubota code 97899-61500, in English with bookmarks and a selectable text layer.
The manual is organized by system: general identification and maintenance, machine body and undercarriage, engine, hydraulic system, and electrical system, plus conversion tables. You get the specifications a real repair needs, including engine oil, hydraulic oil, and fuel capacities, fuel injection pressure, valve clearance, and tightening torques.
Use it to troubleshoot slow or weak hydraulics, chase an engine fault, service the variable-track undercarriage, or check the starter and alternator. It covers pump and valve pressures, flow testing, disassembly and reassembly, and hose routing. Download the PDF once and keep it on a computer, tablet, or phone, and print the pages you need in the field.
What's Inside This Manual
| System | Pages | Key Topics |
|---|---|---|
| General | 5-28 | Identification Marks, Safety Precautions, Servicing Fundamentals, Maintenance Intervals, Fluid Quantities, Service Port Operation |
| Machine Body | 29-128 | Machine Weight & Dimensions, Front Attachment Components, Cab/Canopy Installation, Under Carriage Components, Variable Track Operation, Labeling |
| Engine | 129-264 | Engine Specifications, Engine Mount, Mechanism Overview, Lubricating System, Fuel System, Troubleshooting |
| Hydraulic System | 265-434 | Troubleshooting, Pump & Valve Specifications, Pressure & Flow Testing, Disassembly & Reassembly, Hose Routing |
| Electrical System | 435-473 | Electrical Specifications, Troubleshooting, Wire Harness Installation, Starter & Alternator Checks |
| Conversion Tables | 474-478 |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| All Models | ||
| Tightening torque for M6 (4T) bolts | 7.8 ~ 9.3 N·m | p. 18 |
| Tightening torque for M10 (7T) bolts | 48.0 ~ 55.9 N·m | p. 18 |
| Radiator capacity (Canopy / Cab) | 3.0 L | p. 23 |
| Engine oil with filter capacity | 4.4 L | p. 23 |
| Check engine oil level | daily | p. 20 |
| Change engine oil and oil filter | 250 h | p. 20 |
| Hose Screw Tightening Torque (M12 x 1.5) | 20 ~ 30 N·m | p. 16 |
| Engine Oil Capacity (with filter) | 4.4 L | p. 23 |
| Hydraulic Oil Capacity (Full) | 37.0 L | p. 23 |
| Fuel Tank Capacity | 27.5 L | p. 23 |
| U20-3α | ||
| Engine Gross Output, U20-3α | 14.0 kW / 2200 rpm | p. 32 |
| U25-3α, U25S | ||
| Engine Gross Output (U25-3α, U25S) | 15.5 kW / 2400 rpm | p. 32 |
