All 436 pages of this Yanmar ViO20 service manual pdf (OEM #220104) focus on a single goal: getting your excavator back to factory condition. Inside, you get full hydraulic schematics detailing fluid routing, clear wiring diagrams to trace electrical faults, and an extensive engine troubleshooting section. Open to the service standards chapter to find page after page of tightening torque tables, track roller specifications, and undercarriage rebuild instructions. Fill the travel reduction gear with exactly 0.5L of SAE 90 oil and lock down the track roller tightening nuts to 98.0 N-m. Every hour in the shop costs money. Download the bookmarked file, pull it up on your phone or tablet, and bring the right answers straight to the machine.
What's Inside This Yanmar ViO20 Manual
| System | Pages | Key Topics |
|---|---|---|
| General Cautions for Maintenance Work | 7-18 | Hydraulic Equipment Handling, Hydraulic Piping, Seal Handling, Hydraulic Hose Installation, Hydraulic Hose Specifications |
| Technical Data | 19-31 | Specifications, Outline Drawing, Working Area, Weight List, Lifting Capacity |
| Service Standards | 32-51 | Machine Performance, Engine, Undercarriage, Rubber Crawler, Steel Crawler, Controls, Hydraulic Cylinders, Tightening Torque |
| Engine | 52-94 | Compression Pressure, Valve Clearance, V-Belt, Fuel Injection Valve, Fuel Injection Timing, Cylinder Head, Piston, Crankshaft, Starter Motor, Alternator |
| Hydraulic System | 95-132 | Control Valve Operation, Hydraulic Circuit Schematic, Circuit Operation, Boom, Arm, Bucket, Swing, Travel, Pressure Adjustment, Relief Valves |
| Hydraulic Equipment | 133-311 | Hydraulic Pump, Control Valve, Pilot Valve, Swing Motor, Travel Motor, Pilot Check Valve |
| Adjustment and Repair | 312-388 | Electrical Equipment, Wiring Diagram, Engine Removal, Starter Motor, Undercarriage, Idler, Track Roller, Control Train, Swing Bearing, Hydraulic Cylinders, Swivel Joint, Piping |
| Periodic Inspection and Servicing | 389-391 | Periodic Inspection Schedule, Servicing Intervals |
| Fuel, Lube Oil and Grease | 392-393 | Recommended Fuel, Lubricants, Grease |
| Troubleshooting | 394-433 | Non-Breakdown Phenomena, Machine and Engine Faults, Electrical Equipment on Panel |
| Reference Data | 434-436 | Attachment Specifications |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Track roller tightening nut torque | 57.9 to 72.3 ft·lbf (78.4 to 98.0 N·m) | p. 48 |
| Pipe joint bolt (M12) tightening torque | 18.1 to 25.3 ft·lbf (24.5 to 34.3 N·m) | p. 51 |
| Swing motor to Turning frame tightening torque | 57.9 to 72.3 ft·lbf (78.4 to 98.0 N·m) | p. 49 |
| Travel reduction gear oil type | SAE 90 (GL-4) | p. 393 |
| Travel reduction gear oil capacity | 0.53 Qts. (0.5 L) | p. 393 |
| Hydraulic hose working pressure (SAE J517, 100R1, 02 dia.) | 2489 (17.2) PSI (MPa) | p. 14 |
| Hydraulic pipe joint bolt (M12) tightening torque | 18.1 to 25.3 ft·lbf (24.5 to 34.3 N·m) | p. 51 |
| Fuel-water separator element type | Mesh filter | p. 25 |
| LO filter filtration area | 124.1 (800) sq.in. (sq.cm) | p. 25 |
| LO filter valve opening pressure | 11.4 to 17.1 (0.08 to 0.12) PSI (MPa) | p. 25 |
| Air cleaner filtration area | 9.7 (0.9) sq.ft. (sq.m) | p. 25 |
| Rubber crawler lug height wear limit | 0.39 (10) in. (mm) | p. 41 |
Yanmar ViO20 Common Problems This Manual Covers
Yanmar ViO20 engine rpm drops significantly or stalls completely when operating the boom or bucket cylinders. p. 21
Inspect the hydraulic pump for abnormal noise. Verify the system relief set pressure does not exceed 2986.2 PSI (20.6 MPa) as listed on page 21. Check the engine intake valve clearance and set it to 0.0079 in. (0.2 mm) for a cold engine per page 25.
Manual Section: Hydraulic Pump TroubleshootingMachine pulls to one side during travel or rubber tracks constantly lose tension and slip off idlers. p. 41
Measure the rubber crawler lug height and replace if worn past the 0.39 (10) in. (mm) limit shown on page 41. Inspect the track rollers for abnormal wear and torque the track roller tightening nuts to 57.9 to 72.3 ft-lbf (78.4 to 98.0 N-m) using the specs on page 48.
Manual Section: Service StandardsContinuous hydraulic fluid leaks around the boom cylinder lines and noticeably poor lifting response during operation. p. 51
Check the M12 pipe joint bolts and torque them to 18.1 to 25.3 ft-lbf (24.5 to 34.3 N-m) as specified on page 51. Verify the hydraulic hoses meet the required 2489 (17.2) PSI (MPa) working pressure from page 14 before refilling the 9.24 Gals (35 L) tank.
Manual Section: General Cautions for Maintenance WorkTravel motor does not rotate smoothly or exhibits large fluctuations in motor revolutions during heavy tracking. p. 393
Drain and inspect the travel reduction gear oil for metal shavings. Fill each side with exactly 0.53 Qts. (0.5 L) of fresh SAE 90 (GL-4) gear oil as detailed on page 393. Test the anti-cavitation valve and check for external motor housing leaks before operating.
Manual Section: Travel Motor TroubleshootingFrequently Asked Questions
How do you reset the YANMAR ViO20 hydraulic system?
To re-initialize the hydraulic system after disassembly or parts replacement, you need to release air from it. For hydraulic cylinders, run the engine at a low speed, then extend and retract the cylinders 4 to 5 times up to 1.97 to 3.9 inches (50 to 100 mm) from each stroke end slowly, and then fully extend and retract them 3 or 4 times. For variable displacement piston pumps, install the air bleeder hose onto the bleeder valve and loosen it half a turn to release air, then tighten it and install the cap.
What is the hydraulic oil tank capacity for the YANMAR ViO20?
The hydraulic oil tank capacity for the YANMAR ViO20 is 9.24 gallons (35 liters) in total. This capacity is broken down into 7.92 gallons (30 liters) for the tank itself and 1.32 gallons (5 liters) for other components.
What is the standard intake valve clearance for a cold YANMAR ViO20 engine?
For a cold YANMAR ViO20 engine, the standard intake valve clearance is 0.0079 inches (0.2 mm). This measurement is critical for proper engine operation and should be checked and adjusted as part of maintenance.
What is the tightening torque for the cylinder head bolts on the YANMAR ViO20 engine?
The tightening torque for class 1 cylinder head bolts on the YANMAR ViO20 engine is between 43.4 to 47.0 ft·lbf (58.8 to 63.7 N·m). Lubricating oil should be applied to these bolts before tightening.
What format is this manual in?
A 436-page Service Manual in searchable PDF format, available the moment you complete checkout. View on computer, tablet, or phone, with no shipping wait.
Are there any print restrictions on this manual?
No restrictions at all. Print individual pages, full chapters, or the entire manual. The PDF is completely unlocked.
Can I find hydraulic circuit diagrams in this Yanmar ViO20 manual?
Full hydraulic system diagrams are included, covering circuits, valve locations, and hydraulic component specs for the Yanmar ViO20.
Document Quality
This document is a scanned PDF with an OCR text layer, enabling full text search and selection across all pages. The text is generally crisp and easy to read, although some characters exhibit the slightly reconstructed appearance typical of OCR rather than being natively digital. Diagrams and illustrations are primarily raster images, but they are sufficiently sharp for all labels and details to be clearly legible. The page condition is clean, with only minor, infrequent scan artifacts and no skewed or blank pages.
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