Part of the Yanmar Parts Manuals.
All 248 pages of this Yanmar YB451, YB501 Crawler Backhoe Parts Catalog (OEM #Y00K2094) map factory part numbers for every 1985–1991 YB451(-2) and YB501(-2) variant, covering P, C, and UZ chassis configurations. Inside you get exploded-view diagrams and numbered parts tables across the entire machine: engine mount, fuel system, hydraulic oil pump and piping schematics, control valves, boom and arm cylinders, track frame, swivel joint, turning motor, and full cabin and canopy assemblies. Wiring diagrams detail the complete electrical layout, wire color codes, and harness routing for both canopy and cabin specs. Machine travel is rated at 3.6 km/h high range and 1.9 km/h low range, with ground pressure and model dimensions included in the specifications section. No more ordering the wrong-variant part and waiting a week to find out. Bookmarked by section and searchable by keyword, pull it up on your phone at the parts counter and get the right number on the first call.
What's Inside This Yanmar YB451 / YB501 Series Parts Manual
| System | Pages | Key Topics |
|---|---|---|
| Fuel System | Accelerator, Fuel Tank & Fuel Line | |
| Cooling System | Engine Mount & Radiator | |
| Engine | Silencer, Hyd. Oil Pump & Joint | |
| Electrical System | Wiring Diagram, Battery, Electric Part, Electric Part Fig 15, Electric Part Fig 16, Switch & Quartz Clock | |
| Undercarriage & Travel | Track Roller & Carrier Roller, Track Frame & Idler, Crawler, Travel Motor | |
| PTO | P.T.O. Valve Piping, P.T.O. Valve | |
| Hydraulics & 3-Point Hitch | Hyd. Oil Piping, Hyd. Oil Tank Fig 55, Hyd. Oil Tank Fig 56, Control Valve, Boom Cylinder, Arm Cylinder, Bucket Cylinder, Swing Cylinder, Blade Cylinder, Turning Motor, Swivel Joint, Valve Stopper | |
| Loader, Backhoe & Attachments | Boom & Bucket, Boom & Arm, Blade, Bucket400, Bucket550, Bucket600, Bucket650, Bucket700, Bucket330 | |
| Body & Operator Station | Rear View Mirror, Heater & Defroster, Radio, Turning Frame, Bonnet, Bonnet Fig 35, Bonnet Fig 36, Seat & Step, Seat & Step Fig 38, Seat Mount & Step, Canopy, Cabin Fig 44, Front Open Cabin, Flat Cabin, Cabin Fig 47, Wind Washer | |
| Decals & Accessories | Label, Label Fig 2, Label Fig 3, Label Fig 4, Tool, Greasing | |
| Other Components | Specifications, Parts Name, Control Equipment, Control Equipment Fig 27, Control Equipment Fig 29, Turning Driving Gears, Hook, Lift Pin, Defroster B Fig 84, Defroster B Fig 85, Stereo, B Type Quick Lever |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Travel speed | 3.6 - 1.9 km/h | p. 3 |
Yanmar YB451 / YB501 Series Common Problems This Manual Covers
Hydraulic fluid leaking from the power take-off selector valve or pressure dropping under load
Examine the P.T.O. Valve Piping on page 239. Locate the selector valve body and sub-plate in the parts diagram. Inspect the PT1/16 plug and rubber O-ring for damage. Order the correct replacement spool and seals to prevent further fluid loss.
Manual Section: P.T.O. Valve Piping (U,Uz) (Optional) p. 239Worn bucket side cutters, missing teeth, or excessive play in the attachment pins
Check the Bucket400 (Attachment) exploded view on page 191. Identify the correct replacement side cutter and teeth assembly for your 400 mm bucket setup. Order the matching pin assembly and specific shims to eliminate excess movement and restore digging performance.
Manual Section: Bucket400 (Attachment) p. 191Frequently Asked Questions
What are the replacement specifications for track idler?
The replacement specifications for the track idler include the "IDLER ASSY" (part number 772124-37110 or 172124-37200, quantity 2), "SHAFT, IDLER" (part number 172124-37130, quantity 2), and "SEAL 66 86 28" (part number 933112-00500, quantity 4). These details are found in the "Track Frame & Idler" section. p. 58
What are the replacement specifications for track rollers?
The replacement specifications for track rollers include "ROLLER ASSY, TRUCK" (part number 772124-37300 or 172124-37400, quantity 8), "BUSH, ROLLER" (part number 172124-37310, quantity 16), "SHAFT, ROLLER" (part number 172124-37320, quantity 8), and "SEAL 64 78 25" (part number 933112-00400, quantity 16). These details are found in the "Track Roller & Carrier Roller" section. p. 54
How do you fix yanmar YB451 weak travel power, one track pulling harder than the other, or poor tracking performance?
Check the Travel Motor exploded view on page 187. Locate the required seal set and O-rings for your specific motor assembly. Verify your machine maintains the factory 3.6 - 1.9 km/h travel speed specification. Order the exact replacement parts listed for your serial number. p. 187
How do you fix accelerator pedal feels loose, linkage binding, or third valve stopper failing to hold position?
Review the Valve Stopper diagram on page 243. Inspect the accelerator pivot and conical washer for wear. Replace the M10 cap nut and 10 mm washer if threads are stripped. Match the exact part numbers to ensure the 3rd valve stopper functions properly. p. 243
What format is this manual in?
Instant PDF download. You get the full 248-page searchable Parts Catalog immediately after payment. Open it on your laptop, tablet, or phone right in the shop.
Can I print this manual?
Yes — DRM-free PDF. Print whatever sections you need to take out to the shop. Standard letter or A4 paper works.
Are there wiring harness diagrams in this Yanmar YB451 & variants manual?
A wiring diagram for the Yanmar YB451 & variants electrical system is included.
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