Part of the Yanmar Repair Manuals.
Guess at a torque on a travel motor and a fifteen minute job can end with a machine on blocks and a crew standing around it, which is exactly what the 328 pages of this Yanmar SV20 service manual are there to prevent. It covers the SV20 mini excavator and its 3TNV76-PBVA diesel, from compression measurement and valve clearance through the hydraulic pump, control valve, pilot valve, swing motor and travel motor.
The Service Standards section lists wear limits for the undercarriage, rubber crawlers, idlers and hydraulic cylinders, plus tightening torque tables for machine and engine. Adjustment and Repair walks through removal and reinstallation of the engine, starter motor, fuel injection pump and radiator, with wiring diagrams and the monitor and alarm circuits.
It is a bookmarked PDF, so it lives on a phone or laptop and rides in the cab, on hand wherever the machine quits.
What's Inside This Yanmar SV20 Manual
| System | Pages | Key Topics |
|---|---|---|
| General Cautions for Maintenance Work | 11-24 | Correct Work, Safety Precautions, Preparations, Cautions for Disassembly and Reassembly, Cautions for Removal and Installation of Hydraulic Equipment |
| Technical Data | 25-36 | 2-1 Specifications, 2-2 Outline Drawing and Working Area, 2-3 Weight List of Main Parts, 2-4 Lifting Capacity List |
| Service Standards | 37-56 | Machine Performance, Engine, Undercarriage (Rubber Crawler Specifications, Common Specifications of Steel & Rubber Crawlers), Controls, Hydraulic Equipment (Hydraulic Cylinders) |
| Engine | 57-100 | General (Engine External Views), Measurement |
| Hydraulic System | 101-104 | 5-1 Outline, 5-2 Hydraulic Circuit Schematic |
| Hydraulic Equipment | 105-198 | 6-1 Hydraulic Pump, 6-2 Control Valve, 6-3 Pilot Valve, 6-4 Swing Motor, 6-5 Travel Motor |
| Adjustment and Repair | 199-276 | Electric Equipment of Machine (Parts Layout of Electrical Equipment, Monitor and Alarm Systems, Wiring Diagram, Circuit Description of Engine Start and Stop, And Battery Charging, Removal and Reinstallation of Engine, Removal and Reinstallation of Starter Motor, Removal and Reinstallation of Fuel Injection Pump, Removal and Reinstallation of Fuel Tank, Removal and Reinstallation of Radiator) |
| Periodic Inspection and Servicing | 277-280 | 8-1 List of Periodic Inspection and Servicing |
| Fuel, Lube Oil and Grease Recommended | 281-284 | Engine Oil, Travel Reduction Gear, Hydraulic Oil, Fuel, Engine Cooling Water, Grease |
| Troubleshooting | 285-324 | 10-1 Non-Breakdowns, 10-2 Troubleshooting |
| Reference Data | 325-328 | 11-1 Specifications for Attachment |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| LS pressure relief valve adjustment torque | 20 ± 10% N.m | p. 123 |
| Travel motor valve body assembly to base plate bolts (Hexagon socket head bolt 79) | 14.4 to 15.9 N·m | p. 189 |
| Hydraulic pump cover bolts (Screw Tcei M 10X50 UNI 5931-12.9) | 70 Nm | p. 113 |
| Rubber crawler wear limit (A) | 10 mm | p. 47 |
| Idler & shaft D (diameter) wear limit | Ø279 | p. 45 |
| Hose type (SAE J517, 100R1) 02 working pressure | 17.2 MPa | p. 17 |
| Hose clip 13 tightening torque | 2.5 to 3.4 N·m | p. 52 |
| Floating seal 2 replacement condition | No excessive flaws, wear or seizure | p. 192 |
| Oil seal 30 replacement condition | No flaws, distortion or excessive wear. Not hardened | p. 191 |
| Fuel filter element replacement interval | Every 200 hrs | p. 278 |
| Engine oil filter element replacement interval | Every 250 hrs | p. 277 |
| Air cleaner element replacement interval | Every 250 hrs | p. 277 |
Yanmar SV20 Common Problems This Manual Covers
One track weak, slow, or stopped
When one side crawls while the other pulls, the usual suspects are track tension, undercarriage wear, or the travel motor itself. The manual takes the travel motor apart step by step, including seal inspection points and reassembly torques such as the valve body bolts.
Manual Section: 6. Hydraulic Equipment p. 105Rubber crawler wear and tension loss
Rubber crawlers stretch and shed lugs long before they snap, and a loose track derails on the first hard slew. The manual gives the crawler wear limit of 10 mm plus idler and roller wear diameters so you can measure instead of guessing.
Manual Section: 3. Service Standards p. 37Engine overheating in hot weather
Debris packed into the radiator or a slow coolant leak will push the 3TNV76-PBVA into the red on a long dig. The Engine section covers checking the cooling water system and radiator for leakage alongside V-belt tension.
Manual Section: 4. Engine p. 57Hard starting or rough running
Water in the fuel and clogged filters are the most common reasons an SV20 cranks but will not settle into an idle. The Troubleshooting section works through fuel, intake, and starting faults symptom by symptom, and separates real breakdowns from non-breakdown conditions.
Manual Section: 10. Troubleshooting p. 285Monitor alarms and electrical faults
A dead gauge cluster, a work light that quits, or a starter that clicks once usually traces back to wiring or a switch. This section maps the electrical parts layout, explains the monitor and alarm systems, and includes the full wiring diagram and the start, stop, and charging circuits.
Manual Section: 7. Adjustment and Repair p. 199Hydraulic leaks and sluggish response
A weeping fitting or a boom that drifts under load means chasing oil through the circuit. The hydraulic circuit schematic lets you follow each line from pump to cylinder so you replace the right hose or seal instead of the nearest one.
Manual Section: 5. Hydraulic System p. 101Skipped service intervals catching up
Filters left in past their hours are how small problems become injector and pump problems. The manual lists every periodic inspection item with its interval, including fuel filter element changes every 200 hours.
Manual Section: 8. Periodic Inspection and Servicing p. 277Frequently Asked Questions
Which machine and engine does this manual cover?
It covers the Yanmar SV20 mini excavator with the 3TNV76-PBVA diesel engine. The Technical Data section includes full specifications, outline drawings and working area, a weight list of main parts, and lifting capacities. p. 25
Does it include torque specs and wear limits?
Yes. The Service Standards section carries tightening torque lists for the machine and engine, including undercarriage hardware such as the track roller nuts, plus wear limits for the rubber crawlers, idlers, hydraulic cylinders, and controls. p. 37
Will it help me diagnose a fault without a dealer?
The Troubleshooting section is built for that: it works from the symptom, distinguishes non-breakdown conditions from real faults, and points you to the repair procedure. The wiring diagram and monitor system description in Adjustment and Repair back up any electrical diagnosis. p. 285
How quickly can I access this manual after buying?
Immediate download of the complete 328-page searchable Service Manual. Access it on any device, from a laptop at your desk to a phone in the field.
Can I print this manual?
Yes. The PDF has no DRM restrictions, so print any page or section you need for your shop. Works with any standard printer.
Are hydraulic system diagrams in this Yanmar SV20 Service Manual?
Yes, complete hydraulic schematics with flow diagrams, valve configurations, and pressure specifications are included.
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