Need the correct numbers before placing an order? This 13-page Parts Catalog PDF breaks down every chassis component and hydraulic assembly for your crawler backhoe. You get clear exploded views of the complete roller and adjust mechanisms, plus the control valve sections, crawler assemblies, and hydraulic oil pump components — with OEM part numbers throughout.
What's Inside This Yanmar B25V-1, 3TNE78A - B1A, B6040 Parts Manual
| System | Pages | Key Topics |
|---|---|---|
| Roller & Adjust | 3-4 | Sprocket, Idler Assembly, Mechanism, Track Roller Assembly, Carrier Roller Assembly |
| Crawler | 5-6 | Rubber Component |
| Hyd. Oil Pump & Joint | 7-8 | Hydraulic Oil Pump Assembly, Coupling, Valve Block Assembly, Gear Pump |
| Control Valve (1/2) | 9-10 | T1-Port Components, Bucket Section, Boom Section, Drive Section, P1, P2-Port Components |
| Control Valve (2/2) | 11-13 | Arm Section, P.T.O. Section, T2-Port Components, Turning Section, Blade Section, Control Section, Swing Section |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Relief Valve Setting (Boom/Bucket) | 210/20 | p. 8 |
| Relief Valve Setting (Swing) | 185/31 | p. 8 |
| Relief Valve Setting (Arm) | 220/20 | p. 10 |
| Bolt W/Washer Size | M12X30 | p. 2 |
| Idler Size | 289 | p. 2 |
| Seal Dimensions | 45x85x8.5x19 | p. 2 |
| Collar Dimensions | 35X45X34 | p. 2 |
| Circlip Size | 30 | p. 2 |
| O-Ring 1B Size | P-14.0 | p. 2 |
| Packing G Size | 35.0 | p. 2 |
| Bolt Size | M10X 40 | p. 2 |
| Bearing Type | #6205 | p. 2 |
Yanmar B25V-1, 3TNE78A - B1A, B6040 Common Problems This Manual Covers
Yanmar B25V-1 track tension is loose and undercarriage rattles while traveling in high gear p. 3
Inspect the exploded chassis parts diagram on page 3 to identify the exact idler assembly components. Verify you require the 289 size idler for your machine. Cross-reference the #6205 bearing type and 35X45X34 collar dimensions on page 2 to order the correct replacement hardware.
Manual Section: Roller & AdjustMain hydraulic pump makes a loud whining noise when operating the boom or bucket cylinders p. 7
Check the pump assembly breakdown on page 7 to identify the worn gear pump components. Match your serial number to ensure you order the correct valve block assembly. Confirm the boom/bucket relief valve setting is 210/20 on page 8 when replacing the joint fittings.
Manual Section: Hyd. Oil Pump & JointArm cylinder lacks digging force and feels extremely weak during heavy trenching operations p. 11
Review the arm section exploded diagram on page 11 to locate the specific spool and O-ring part numbers. Verify the arm relief valve setting of 220/20 on page 10. Order the exact seals and P.T.O. section components required for a complete control valve rebuild.
Manual Section: Contorol Valve (2/2)Track roller assembly is leaking hydraulic oil onto the rubber crawler pads p. 3
Locate the track roller assembly diagram on page 3. Find the correct 45x85x8.5x19 seal dimensions on page 2 to stop the fluid leak. Secure the new components using M12X30 bolts with washers to ensure the undercarriage stays tight during heavy digging operations.
Manual Section: Roller & AdjustFrequently Asked Questions
How do you fix track tension is loose and undercarriage rattles while traveling in high gear?
Inspect the exploded chassis parts diagram on page 3 to identify the exact idler assembly components. Verify you require the 289 size idler for your machine. Cross-reference the #6205 bearing type and 35X45X34 collar dimensions on page 2 to order the correct replacement hardware.
How do you fix main hydraulic pump makes a loud whining noise when operating the boom or bucket cylinders?
Check the pump assembly breakdown on page 7 to identify the worn gear pump components. Match your serial number to ensure you order the correct valve block assembly. Confirm the boom/bucket relief valve setting is 210/20 on page 8 when replacing the joint fittings.
How do you fix arm cylinder lacks digging force and feels extremely weak during heavy trenching operations?
Review the arm section exploded diagram on page 11 to locate the specific spool and O-ring part numbers. Verify the arm relief valve setting of 220/20 on page 10. Order the exact seals and P.T.O. section components required for a complete control valve rebuild.
How do you fix track roller assembly is leaking hydraulic oil onto the rubber crawler pads?
Locate the track roller assembly diagram on page 3. Find the correct 45x85x8.5x19 seal dimensions on page 2 to stop the fluid leak. Secure the new components using M12X30 bolts with washers to ensure the undercarriage stays tight during heavy digging operations.
How will I receive this Parts Catalog?
Instant PDF download. You get the full 13-page searchable Parts Catalog immediately after payment. Open it on your laptop, tablet, or phone right in the shop.
Can I print specific sections of this Parts Catalog?
Yes. The PDF has no DRM restrictions, so print any page or section you need for your shop. Works with any standard printer.
Document Quality
This document is primarily a scanned PDF, but it includes an OCR layer, so you can search and copy most of the text content. The text quality is crisp and easy to read throughout the document. All diagrams and illustrations are raster images, which means they may pixelate when highly magnified, but their labels and details remain clear and readable. The pages are clean, free of scan artifacts, stains, or skewed content, ensuring a good visual experience. There are no notable blank or filler pages present.
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