Part of the Yanmar Parts Manuals.
A split fuel hose on a 1986 Yanmar crawler backhoe is a ten-minute swap, once you know which part number to order. This parts catalog for the YB121U and YB151U, including the -2, R, canopy, and cabin versions, walks the machine end to end: fuel tank and lines, battery and electrics, hydraulic piping, pump and cylinders, travel motor, track rollers and crawler, turning frame, and the operator station.
Guessing at parts is how a small backhoe ends up parked for a week waiting on the wrong seal kit. Here every assembly is broken out with Yanmar part numbers, so you can match what is on your machine (serial numbers 10501 onward and 20501 onward, 3TNA72L-UBVM diesel) before you spend anything.
The PDF runs 178 pages with 77 bookmarks, so jumping from the wiring diagram to the bucket cylinder takes seconds. Buy it once, download it, and it stays on your drive for as long as you own the machine.
What's Inside This Parts Manual
| System | Pages | Key Topics |
|---|---|---|
| Electrical System | Wiring Diagram, Battery, Electric Part | |
| Undercarriage & Travel | Travel Motor | |
| Rear Axle, Differential & Brakes | Brake Valve | |
| Hydraulics & 3-Point Hitch | Hyd. Oil Piping, Hyd. Oil Tank, Control Valve, Bucket Cylinder, Turning Motor, 3rd Valve Piping | |
| Loader, Backhoe & Attachments | Boom & Bucket, Bucket 250, Bucket 300, Bucket 350, Bucket 450, Bucket 250W, Bucket 300W, Bucket 350W, Bucket 450W | |
| Body & Operator Station | Turning Frame, Bonnet, Seat & Step, Canopy, Cabin, Heater & Defroster, Wind Washer | |
| Decals & Accessories | Tool | |
| Other Components | Specifications, Inlet House & Exhaust Pipe, Control Equipment |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| FUSE | 5A | p. 28 |
