Part of the Yanmar Repair Manuals.
When the boom drifts down on a Yanmar B25V and there is no dealer within a day's drive, the question is not whether the machine can be fixed but where the pressure spec lives. It lives here, in the 402 page factory service manual for the B25V excavator and its 3TNE78A-B1A diesel, publication 44199040.
The book walks through the engine from compression pressure measurement to crankshaft inspection, then covers the full hydraulic side: circuit schematics, relief valve pressure adjustment, and step by step disassembly of the pump, pilot valves, swing motor, and travel motor. Servicing standards give wear limits for the undercarriage and hydraulic cylinders, with tightening torques alongside.
You download the PDF, open it next to the machine, and follow the same procedures a Yanmar technician would, whether that is setting fuel injection timing or chasing a fault through the troubleshooting tables until the excavator is back to work.
Complete the set for your B25V
- Repair Manual: Yanmar B25V Operation Manual (incl. Wiring)
What's Inside This Yanmar B25V Manual
| System | Pages | Key Topics |
|---|---|---|
| General Cautions for Maintenance Work | 11-21 | Correct Work, Safety Precautions, Preparations, Cautions for Disassembly and Reassembly, Cautions for Removal and Installation of Hydraulic Equipment |
| Technical Data | 23-30 | Main Specifications, Traveling Performance, Hydraulic Implement, Engine Specifications, Electrical Equipment |
| Servicing Standards | 32-46 | Machine Performance, Engine Standards, Undercarriage Specifications, Hydraulic Cylinder, Tightening Torque |
| Engine | 48-100 | Compression Pressure Measurement, Valve Head Clearance, Fuel Injection Timing, Cooling System Check, Crankshaft Inspection |
| Hydraulic System | 102-170 | System Outline, Control Valve Operation, Hydraulic Circuit Schematic, Pressure Adjustment, Relief Valves, Cut-Off Valve |
| Hydraulic Equipment | 172-266 | Hydraulic Pump Disassembly, Control Valve Operation, Pilot Valve Disassembly, Swing Motor, Travel Motor |
| Adjustment and Repair | 268-319 | Electric Equipment Arrangement, Monitor and Alarm Systems, Undercarriage Reassembly, Control Linkage Adjustment, Hydraulic Oil Tank |
| Fuel, Lube Oil and Grease Recommended | 324-325 | Fuel Type, Engine Oil, Hydraulic Oil, Grease Type, Cooling Water |
| Troubleshooting | 327-360 | Non-Breakdowns, Machine and Engine Troubleshooting, Electrical Equipment on Panel, Hydraulic System Issues |
| Reference Data | 362-363 | Specifications for Attachment, Bucket Installation, Hydraulic Specifications |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Hydraulic Oil Tank Capacity | 76 L | p. 28 |
| Max. Engine Output | 14.0 kW (19.1 PS) at 2100 rpm | p. 29 |
| Compression Pressure | 32 ± 1 kgf/cm² | p. 29 |
| Fuel Injection Pressure | 200 to 210 kgf/cm² | p. 30 |
