Part of the Yanmar Repair Manuals.
Put a pressure gauge on a ViO55-5 that travels weak on one side and this manual tells you what the reading should be and which adjuster to turn when it is not. It is the Yanmar factory service manual, publication A470608, for the ViO45-5, ViO45-5B, ViO55-5 and ViO55-5B mini excavators, serial numbers 50501 and after, with the 4TNV88-PBV and 4TNV88-BXB V engines.
Across 201 pages it moves from technical data and lifting capacities into service standards for the undercarriage, controls, cylinders and attachments, then a full engine section with troubleshooting, inspection and adjustment, lubrication, cooling and the fuel injection pump and governor, and finally the hydraulic system with circuit schematic, circuit operation and pressure adjustment.
For an owner or independent wrench, that is the difference between swapping parts on a hunch and setting the machine back to factory numbers before the crew loses a second day.
What's Inside This Yanmar ViO45-5, ViO45-5B, ViO55-5, ViO55-5B Manual
| System | Pages | Key Topics |
|---|---|---|
| General Cautions for Maintenance Work | 9-20 | Correct Work, Safety Precautions, Preparations, Cautions for Disassembly and Reassembly, Cautions for Removal and Installation of Hydraulic Equipment |
| Technical Data | 21-57 | Specifications, Outline Drawing and Working Area (Canopy Type, Cabin Type), Weight List of Main Parts, Lifting Capacity List |
| Service Standards | 58-81 | Machine Performance, Engine, Undercarriage (Rubber Track Specifications, Steel Track Specifications, Common Specifications of Steel & Rubber Tracks), Controls |
| Engine | 82-159 | 4-1 General, 4-2 Troubleshooting, 4-3 Inspection and Adjustment, 4-4 Engine Body, 4-5 Lubrication System, 4-6 Cooling System, 4-7 Fuel Injection Pump / Governor |
| Hydraulic System | 160-201 | 5-1 Outline, 5-2 Hydraulic Circuit Schematic, 5-3 Circuit Operation, 5-4 Pressure Adjustment |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Travel motor × Track frame tightening torque | 86.8 to 108.5 ft·lbf (117.7 to 147.1 N·m) | p. 77 |
| Hose type 2 (SAE J517, 100R2) dia. 02 working pressure | 4264 PSI (29.4 MPa) | p. 16 |
| Drain plug 24 × Hydraulic oil tank tightening torque | 78.0 ft·lbf (105.8 N·m) | p. 77 |
| Hydraulic pump - Number of pumps | Piston pump: 2 + Gear pump: 2 | p. 23 |
Yanmar ViO45-5, ViO45-5B, ViO55-5, ViO55-5B Common Problems This Manual Covers
Weak travel or dig on one side
A ViO that pulls harder on one track or loses power on one stick usually has a pilot, valve or pump problem, not a worn motor. The hydraulic circuit operation and pressure adjustment procedures let you test each circuit and set relief pressures instead of guessing.
Manual Section: 5. Hydraulic System p. 160Rubber track wear and tension problems
Loose tracks derail on turns and over-tight tracks eat idlers and final drive seals. The service standards give separate wear limits for rubber and steel tracks plus the common undercarriage specifications, so you know what to shim, tension or replace.
Manual Section: 3. Service Standards p. 58Hard starting and rough running
The 4TNV88 troubleshooting section works from symptom to cause with a quick reference table, then hands you the inspection and adjustment procedures to confirm the fault before you open the engine.
Manual Section: 4. Engine p. 82Engine overheating under load
Overheating on a mini excavator working at full stick is often a cooling system fault that shows up only under load. The cooling system coverage in the engine section walks through inspection so you can rule out components in order.
Manual Section: 4. Engine p. 82Fuel injection pump and governor faults
Surging idle, black smoke or a machine that dies under load points at the fuel injection pump and governor. The engine section covers this system directly, along with the adjustments that keep you from making it worse.
Manual Section: 4. Engine p. 82Leaking hydraulic hoses and seals
Old hoses weep at the crimps and seals fail after careless reassembly. The opening section covers correct hydraulic hose installation, hose specifications, seal handling and air release of hydraulic equipment, the steps most leaks trace back to.
Manual Section: 1. General Cautions for Maintenance Work p. 9Boom and arm cylinders drifting down
A load that settles with the levers centered means worn cylinder internals or valve leakage. Service standards for the hydraulic cylinders and front attachments give you the limits to measure against before you commit to a reseal.
Manual Section: 3. Service Standards p. 58Frequently Asked Questions
Which machines does this manual cover?
It covers the Yanmar ViO45-5, ViO45-5B, ViO55-5 and ViO55-5B excavators, serial numbers 50501 and after, including both canopy and cabin types. Engine coverage is for the 4TNV88-PBV and 4TNV88-BXB V diesels. The Yanmar publication number is A470608. p. 21
Does it include torque specs for the undercarriage and travel motors?
Yes. The Service Standards section includes a list of tightening torques for the machine and engine, including travel motor to track frame bolts, plus a table for general bolts and nuts. p. 58
Can I use it to test and adjust hydraulic pressures?
Yes. The Hydraulic System section includes the circuit schematic, circuit operation and a pressure adjustment procedure, which is what you need to diagnose weak travel, slow functions or one side losing power against the other. p. 160
How will I receive this Service Manual?
A 201-page Service Manual in searchable PDF format, available the moment you complete checkout. View on computer, tablet, or phone, with no shipping wait.
Is this Yanmar ViO45–ViO55 Series Service Manual printable?
No copy protection at all. The PDF is DRM-free, so print whatever sections you need to take to the shop. Standard letter or A4 paper works.
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