Need the factory numbers for your undercarriage rebuild? This 202-page Yanmar C12R Service Manual PDF (OEM #0BKC2-EN0010) breaks down every engine, H.S.T., and track assembly procedure for the C12R and C12R (3WD) excavators. You get complete hydraulic circuit schematics, clear wiring diagrams for the monitor and alarm systems, and a full troubleshooting section dedicated entirely to the hydrostatic transmission. Inside, expect to find detailed service standards with exact wear limits for the cylinder head, piston rings, and trochoid pump. Verify the fuel injection pressure sits between 1711 and 1842 PSI, then lock down the track roller assembly nuts to exactly 115.7 ft-lbf before rolling out. Your machine is down. Grab this bookmarked file, pull it up on your tablet, and fix the problem right the first time.
What's Inside This Yanmar C12R, C12R (3WD) Manual
| System | Pages | Key Topics |
|---|---|---|
| Chapter 1 General Cautions for Maintenance Work | 6-17 | 1. General Cautions for Maintenance Work |
| Chapter 2 Technical Data | 18-27 | Specifications, Machine Dimensions, Hydraulic Circuit Schematic, Wiring Diagram, Weight of Components |
| Chapter 3 Service Standards | 28-41 | Machine Performance, Engine, Undercarriage, Control Devices, Hydraulic Cylinder, Work Implement, List of Tightening Torque (Machine) |
| Chapter 4 Engine | 42-86 | Measurement |
| Chapter 5 Structure and Operation | 87-98 | Electrical Equipment of Machine (Parts Layout of Electrical Equipment, Monitor and Alarm Systems, Wiring Diagram, Circuit Description of Engine Start and Stop, Circuit Description of Battery Charging) |
| Chapter 6 Hydraulic Equipment | 99-132 | Hydraulic Cylinder, Hydraulic Oil Tank, Hydraulic Piping |
| Chapter 7 Structure and Operation | 133-184 | Electrical Equipment of Machine (Parts Layout of Electrical Equipment, Monitor and Alarm Systems, Wiring Diagram, Circuit Description of Engine Start and Stop, Circuit Description of Battery Charging) |
| Chapter 8 Periodic Inspection and Servicing | 185-187 | 8. Periodic Inspection and Servicing |
| Chapter 9 Fuel, Lube Oil and Grease Recommended | 188-189 | 9. Fuel, Lube Oil and Grease Recommended |
| Chapter 10 Troubleshooting | 190-201 | Machine and Engine, H.S.T. |
| Colophon | 202 | - |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Track roller ass'y tightening torque | 115.7 to 123.0 ft-lbf (156.8 to 166.6 N•m) | p. 35 |
| Oil seal 24 cover screws tightening torque | 4.7 ft-lbf (6.4 N•m) | p. 124 |
| Fuel injection pressure | 1711 to 1842 PSI (11.8 to 12.7 MPa) | p. 22 |
| Radiator hose clip tightening torque | 1.81 to 2.17 ft-lbf (2.45 to 2.94 N•m) | p. 35 |
| Engine oil pressure switch working pressure | 5.69 to 8.53 PSI (0.04 to 0.06 MPa) | p. 135 |
| Engine Oil Pan Capacity | 1.90 Qts. (1.8 L) | p. 189 |
| Hydraulic Oil System Capacity | 4.36 Gals. (16.5 L) | p. 189 |
| Fuel Tank Capacity | 3.83 Gals. (14.5 L) | p. 189 |
| Dump Cylinder Nut Tightening Torque | 217 to 253 ft-lbf (294 to 343 N•m) | p. 38 |
| Engine Minimum Idling Speed | 1075 to 1125 rpm | p. 21 |
| Glow Plug Tightening Torque | 11.07 to 14.76 ft-lbf (15 to 20 N•m) | p. 86 |
Yanmar C12R, C12R (3WD) Common Problems This Manual Covers
Yanmar C12R hydraulic system loses pressure after 10 minutes of operation, bucket won't lift p. 19
Test the hydraulic system relief set pressure. Ensure it reads between 2233 to 2318 PSI (15.4 to 16.0 MPa) as specified on page 19. Inspect the main pump seal rings and replace any leaking components. Refill the tank to the 4.36 Gals. (16.5 L) capacity.
Manual Section: Chapter 2 Technical DataEngine overheats when running under full load in hot weather, shutting down unexpectedly p. 135
Inspect the coolant system and radiator for restrictions. Check the engine oil pressure switch on page 135 to verify it trips at 5.69 to 8.53 PSI (0.04 to 0.06 MPa). Drain the old oil and refill the pan with exactly 1.90 Qts. (1.8 L) of fresh fluid.
Manual Section: Chapter 7 Structure and OperationEngine starts but fails to reach rated RPM under load, operation feels sluggish p. 21
Measure the engine minimum idling speed to confirm it runs at 1075 to 1125 rpm as shown on page 21. Check the air cleaner element and replace it if you have exceeded the 500 hours replacement frequency. Clean the fuel injectors to restore proper throttle response.
Manual Section: Chapter 2 Technical DataStarter motor does not turn over or battery dies quickly in cold weather p. 86
Verify the battery charge and inspect the wiring harness for shorts. Test the glow plugs and tighten the bodies to 11.07 to 14.76 ft-lbf (15 to 20 N•m) as detailed on page 86. Clean all sensor connectors to prevent voltage drops across the start circuit.
Manual Section: Chapter 4 EngineFrequently Asked Questions
How do I adjust the travel pedal or drive system?
The manual does not describe a 'reset' procedure for the travel pedal or drive system. However, it provides inspection and adjustment procedures for the travel pedal. To adjust the travel pedal, move the F/R lever from the neutral position to the forward or reverse travel position, press down on the brake pedal fully, and then start the engine. Check that the play of the travel pedal is between 0.2 in. (5 mm) and 1.0 in. (25 mm). If adjustment is needed, loosen the lock nut and slowly turn the return spring to find the point at which the machine starts moving.
What are the torque specifications for track roller nuts?
The tightening torque for the track roller assembly nuts (M16 fine thread) is specified as 115.7 to 123.0 ft-lbf (156.8 to 166.6 N•m).
Why won’t my machine move forward or reverse?
If the machine does not travel normally, potential causes include slack in the V-belt, improper operation of the control equipment, the parking brake not being released, or wear/damage to the transmission fork or gears. The troubleshooting flowchart suggests checking these items and adjusting V-belt tension or control equipment play, or repairing/replacing worn parts.
How do I release the park brake?
To release the parking brake, step on the brake pedal (1) with a force of 44 to 66 lbs. (20 to 30 kgf), then pull back the parking lever (2). The manual also describes adjusting the bite of the lever to 2 to 3 notches with the turnbuckle (4).
Is this Service Manual a digital download?
Instant PDF download. You get the full 202-page searchable Service Manual immediately after payment. Open it on your laptop, tablet, or phone right in the shop.
Can I print specific sections of this Service Manual?
Yes, print as many copies as you want, and there are no restrictions. Many mechanics print the section they need and bring it to the shop floor.
Are electrical wiring diagrams included in this manual?
Yes. You'll find full electrical schematics with wire routing diagrams, connector identification, and circuit descriptions.
Document Quality
This is a high-quality, native digital PDF document, allowing you to search and copy the full text. All text is crisp and clear, making it very easy to read. Diagrams and illustrations are a mix; some are sharp vector-like images with readable labels, while others are clear raster images. The pages are clean with no noticeable scan artifacts, stains, or skewed content. There are no notable blank or filler pages in the document.
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