Need the correct factory specifications to get your compact crawler carrier back on the dirt? This 34-page Yanmar C20R service manual pdf breaks down the complete 3TNA72L series engine, powertrain, and undercarriage systems. Inside, you get clear system diagrams, detailed exploded views of control devices, and complete clearance tables. Open up any section to find factory test values for the hydraulic cylinders and complete torque specifications for the entire work implement. Secure the engine base fixing bolts to exactly 4.5 to 6.0 kgf·m and verify you are running the correct 12-36 V-Ah, 46B24L-MF battery before turning the key. Wrenching without real numbers is a fast track to a comeback. Download this file to your phone, use the bookmarks to find your exact procedure, and fix your machine today.
What's Inside This Yanmar C20R Manual
| System | Pages | Key Topics |
|---|---|---|
| 1-34 | Engine, Power Train Equipment, Undercarriage, Control Devices, Hydraulic Cylinder, Work Implement, Torque Specifications |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| C20R | ||
| Engine base fixing bolt tightening torque | 4.5~6.0 kgf·m | p. 31 |
| Battery type | 46B24L-MF | p. 8 |
| Battery voltage - 5 hrs rate capacity | 12-36 V-Ah | p. 8 |
| Battery tightening nut (Under) torque | 0.2~0.4 kgf·m | p. 31 |
| Battery tightening nut (Over) torque | 0.8~1.2 kgf·m | p. 31 |
| Starter motor nominal output | 12-1.0 V-kW | p. 8 |
| Starter motor engagement | Magnetic shift | p. 8 |
| FO filter type | Paper type element | p. 7 |
| Hydraulic oil type (also used as transmission oil) | Yanmar super royal oil SAE 10W-30 Diesel engine oil SAE 10W-30 API CD class | p. 14 |
| Idler Fixing Nut Tightening Torque | 35.0~45.0 kgf·m | p. 31 |
| 3TNA72L series | ||
| Intake Valve Clearance (Cold eng.) | 0.15~0.25 mm | p. 21 |
Yanmar C20R Common Problems This Manual Covers
Yanmar C20R crawler carrier engine cranks slowly or will not start in cold weather p. 31
Inspect the battery condition and terminals. Verify you have a 46B24L-MF battery rated for 12-36 V-Ah on page 8. Clean corroded posts and torque the over nuts to 0.8~1.2 kgf·m as shown on page 31. Test the starter motor output to confirm it hits 12-1.0 V-kW.
Manual Section: General Torque SpecificationsTrack drive feels imbalanced and machine pulls to one side during travel operation p. 23
Measure clutch plate thickness to determine if friction material is worn. Replace the clutch assembly if thickness falls below the 1.0 mm wear limit A indicated on page 23. Check the brake bands for oil contamination and bleed air from the travel circuit to restore even response.
Manual Section: Power Train Equipment Servicing StandardsSlow hydraulic response and visible oil leakage around the pump and control lines p. 32
Check the hydraulic oil level and add Yanmar super royal oil SAE 10W-30 if below the 14 l capacity limit noted on page 14. Inspect all line connections for leaks. Torque any loose 1/4 inch hydraulic hoses to 2.5 kgf·m according to the specs on page 32.
Manual Section: General Torque SpecificationsRubber tracks skip over the sprocket and feel loose during heavy load dumping p. 25
Verify the undercarriage component wear. Replace the rubber track if the tread depth reaches the 8 mm wear limit A found on page 25. Adjust track tension and torque the idler fixing nut to 35.0~45.0 kgf·m as specified on page 31 to prevent future slippage.
Manual Section: Undercarriage Servicing StandardsEngine misfires and lacks power when climbing steep grades under full load conditions p. 21
Remove the valve cover and check intake valve clearance on a cold engine. Adjust the clearance to 0.15~0.25 mm using the values on page 21. Check the paper type element fuel filter for restrictions and verify total engine displacement matches the 879 cc specification on page 7.
Manual Section: Engine Servicing StandardsFrequently Asked Questions
What are the torque specs for a YANMAR C20R?
The service manual provides detailed torque specifications for various components of the YANMAR C20R. For instance, the engine base fixing bolt (M10) should be tightened to 4.5~6.0 kgf·m. General bolts and nuts, Allen-head plugs, hydraulic hoses, and grease nipples also have specified tightening torques.
What are the replacement specifications for battery?
The YANMAR C20R uses a 46B24L-MF battery type. The battery voltage with a 5-hour rate capacity is specified as 12-36 V-Ah.
What is the engine oil capacity for the YANMAR C20R?
The engine oil capacity for the YANMAR C20R is 2.4 liters. The recommended oil type is Yanmar super royal oil SAE 10W-30 or Diesel engine oil SAE 10W-30 API CD class.
What type of fuel is recommended for the YANMAR C20R?
The YANMAR C20R is designed to use Diesel light oil JIS No.2. The fuel tank capacity is 19 liters.
What is the total capacity of the hydraulic oil tank for the YANMAR C20R?
The hydraulic oil tank capacity for the YANMAR C20R is 14 liters, using transmission oil which is also used as hydraulic oil. The recommended oil is Diesel engine oil SAE 10W-30 API CD class.
What do I get after purchasing this Yanmar C20R manual?
You get a 34-page searchable PDF that downloads instantly after checkout. Open it on your laptop, tablet, or phone, and bring it right to the shop floor.
Am I able to print pages from this manual?
Absolutely. No DRM or copy protection. Print the whole manual or just the pages you need. Any home or office printer works.
Document Quality
This document is a scanned PDF with an optical character recognition (OCR) layer, allowing you to search and copy the full text. The text throughout is crisp and easy to read, with no blurriness or fading. Diagrams and illustrations are clear raster images, and all labels are perfectly readable. Pages are clean with no significant scan artifacts or marks, though some page borders are slightly wavy. Please note that pages 2, 4, 18, and 33 are intentionally blank.
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