All 280 pages of this Yanmar B2U-1 Parts Catalog (OEM #Y00K3631) cover one machine: the 1998 crawler backhoe, broken down system by system from engine mount to track roller. Inside, you get exploded views with OEM part numbers across engine-related components, hydraulic oil system, revolving frame, undercarriage, boom, and cab, with every assembly mapped to the individual piece. Wiring diagrams for the starter, alternator, battery, and monitor circuit are included, so you can trace an electrical path or pin down a harness clip without guessing. Match your 3TNE74-N3AY or 3TNE74-EN3AY engine to the correct variant before ordering: the boom seal is 35mm x 45mm x 4mm, and that lower frame spring pin is 4mm x 8mm. Wrong part ordered twice already? Bookmarked by system and searchable by keyword; open it on your phone, find the part number, and order right the first time.
What's Inside This Yanmar B2U-1 Parts Manual
| System | Pages | Key Topics |
|---|---|---|
| Preface | 1 | Parts Catalog History, Model Name, Yanmar Genuine Parts |
| Vehicle Painted Color | 2 | Painted Color, Main Parts, Under Traveling Body, Work Equipment, Canopy, Monitor |
| Paint Part No. | 3 | Painted Color, Munsell No., Color Division, Spray CAN |
| Wiring Diagram (1) | 4 | Starter, Alternator, Battery, Monitor, Fuel Sensor, Horn |
| Wiring Diagram (2) | 5 | Wiring Harness, Connector Routing, Fuse Box, Relay, Cab Harness, Ground Points |
| Picturesque Indx(1) | 6 | Engine Related Parts, Hyd. Oil System, Fuel Tank, Radiator, Oil Cooler, Electric Part |
| Picturesque Indx(2) | 7 | Operator Compartment, Control System, Canopy, Operator Seat, Floor Mat, Control Equipment |
| Picturesque Indx(3) | 8 | Under Carriage, Turning Related Parts, Travel, Swivel Joint, Track Roller, Track Frame |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Part: Gasket size | 10 | p. 14 |
| Part: Spring Pin dimensions | 4mm x 8mm | p. 170 |
| Part: O-Ring 1A P-dimension | P-18.0 | p. 108 |
| Part: Shim thickness | 1.0mm | p. 170 |
| Part: Seal dimensions | 35mm x 45mm x 4mm | p. 174 |
| Part: Bulb wattage | 60W | p. 190 |
| Part: Circlip size | 52 | p. 228 |
| Part: O-Ring 1B P-dimension | P-11.0 | p. 248 |
Yanmar B2U-1 Common Problems This Manual Covers
Yanmar B2U-1 hydraulic hose part numbers unclear, multiple hoses on the machine look identical p. 6
Start with the system overview on page 6 to place each hose position in context, then turn to the hydraulic parts diagram for individual hose and fitting part numbers. The O-ring listed on page 108 carries a P-18.0 dimension. Match each hose by its position in the exploded view; visually identical hoses often carry different pressure ratings and distinct part numbers.
Manual Section: Picturesque Indx(1)Boom cylinder seal kit part number needed, seal dimensions on hand do not match installed seals
Open the boom and attachment parts diagram, find the cylinder assembly in the exploded view, and note the seal kit part number. The seal dimensions for this assembly are 35mm x 45mm x 4mm (page 174). Cross-reference the part number in the parts list to verify compatibility with your serial number range before ordering.
Manual Section: Boom & Attachment Parts DiagramTrack roller, idler, and sprocket part numbers needed, undercarriage exploded view layout is confusing p. 8
Begin with the undercarriage pictographic index on page 8 to place rollers, idlers, and the track frame in context. Then go to the chassis parts diagram and drivetrain diagram for individual part numbers. The exploded views list front idler and track roller assemblies separately; confirm the exact sub-assembly before ordering.
Manual Section: Picturesque Indx(3)Fuse or wiring connector part number needed after intermittent electrical fault, components look interchangeable p. 4
Pull up wiring diagram (1) on page 4 for the starter, alternator, battery, and monitor circuits; page 5 continues the harness layout. Identify the fuse or connector by circuit position in the diagram, not by appearance. Connectors in the same harness share a housing style but carry different pin counts. Cross-reference the part number in the parts list.
Manual Section: Wiring Diagram (1)Engine filter part numbers needed for air filter, fuel filter, and oil filter all requiring replacement at the same interval
Go to the engine parts diagram for all three filter part numbers. Check the system overview on page 6 first to confirm each filter's location in the engine compartment before cross-referencing the detail diagram. Order Yanmar genuine part numbers only; aftermarket filter thread specs and dimensions often differ from OEM even when packaging claims a direct fit.
Manual Section: Engine Parts DiagramCab interior light bulb burned out, replacement part number and socket type unknown
Check the cab and interior parts diagram to locate the light assembly and its part number in the exploded view. The verified bulb wattage for this machine is 60W (page 190). Confirm the socket type from the diagram before ordering; installing a higher-wattage replacement risks damaging the wiring harness and surrounding trim.
Manual Section: Cab & Interior Parts DiagramFrequently Asked Questions
How do you fix yanmar B2U-1 hydraulic hose part numbers unclear, multiple hoses on the machine look identical?
Start with the system overview on page 6 to place each hose position in context, then turn to the hydraulic parts diagram for individual hose and fitting part numbers. The O-ring listed on page 108 carries a P-18.0 dimension. Match each hose by its position in the exploded view; visually identical hoses often carry different pressure ratings and distinct part numbers.
How do you fix boom cylinder seal kit part number needed, seal dimensions on hand do not match installed seals?
Open the boom and attachment parts diagram, find the cylinder assembly in the exploded view, and note the seal kit part number. The seal dimensions for this assembly are 35mm x 45mm x 4mm (page 174). Cross-reference the part number in the parts list to verify compatibility with your serial number range before ordering.
How do you fix track roller, idler, and sprocket part numbers needed, undercarriage exploded view layout is confusing?
Begin with the undercarriage pictographic index on page 8 to place rollers, idlers, and the track frame in context. Then go to the chassis parts diagram and drivetrain diagram for individual part numbers. The exploded views list front idler and track roller assemblies separately; confirm the exact sub-assembly before ordering.
How do you fix fuse or wiring connector part number needed after intermittent electrical fault, components look interchangeable?
Pull up wiring diagram (1) on page 4 for the starter, alternator, battery, and monitor circuits; page 5 continues the harness layout. Identify the fuse or connector by circuit position in the diagram, not by appearance. Connectors in the same harness share a housing style but carry different pin counts. Cross-reference the part number in the parts list.
How quickly can I access this manual after buying?
This is a 280-page searchable PDF ready for immediate download. Works on any device, so pull it up on your phone while you're under the hood. No shipping, no waiting.
Am I able to print pages from this manual?
Yes. The PDF has no DRM restrictions, so print any page or section you need for your shop. Works with any standard printer.
Does this Yanmar B2U-1 Parts Catalog have electrical diagrams?
A wiring diagram for the Yanmar B2U-1 electrical system is included.
Document Quality
This is a scanned document, but it features a high-quality OCR layer, allowing you to search and copy the full text content. The original text from the scanned pages is crisp and consistently easy to read throughout. All diagrams and illustrations are clear raster images with perfectly legible labels. The pages are clean, showing no significant scan artifacts, stains, or skewed content, and there are no blank or filler pages.
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