All 994 pages of this Yanmar B55W-2 Service Manual (OEM #K1038983AE) are built around one machine: the B55W-2 Wheel Excavator, from upper structure teardown to hydraulic circuit diagnostics. Inside you get full hydraulic schematics for the B55W-2 circuit, wiring diagrams for the complete electrical system, and a dedicated troubleshooting section covering the main control valve, swing motor, and travel motor. Packed alongside are 70 error codes, system diagrams for every major circuit, and page after page of torque tables spanning the engine, transmission, and attachment components. Swap your hydraulic filter every 250 hours (after the initial 50-hour break-in) and tighten the fuel filter to 14-17 ft·lb: both intervals and specs are spelled out exactly as Yanmar printed them. Your machine is down and the dealer wants a week. Bookmarked by section and keyword-searchable; open it on any device, find the spec, and start wrenching.
What's Inside This Yanmar B55W-2 Manual
| System | Pages | Key Topics |
|---|---|---|
| Safety | 9-54 | Wheel Excavator Safety (Safety Precautions, Applicable Models, To the Operator of a Excavator, Location of Safety Labels, Summary of Safety Precautions for Lifting in Working Mode, Unauthorized Modifications, Before Starting Engine, Machine Operation, Maintenance, Battery, Towing, Shipping and Transportation, Lifting with Sling) |
| Specifications | 55-86 | Specification for DX55W |
| General Maintenance | 87-126 | General Maintenance Procedures, Standard Torques |
| Upper Structure | 127-184 | Cabin, Counterweight, Fuel Tank, Fuel Transfer Pump, Swing Bearing |
| Lower Structure and Chassis | 185-258 | Ram Lock Valve, Axle |
| Engine and Drive Train | 259-582 | Engine, Transmission, Drive Coupling (Main Pump) |
| Hydraulics | 583-905 | Hydraulic System Troubleshooting, Testing and Adjustment, Accumulator, Center Joint, Cylinders, Main Control Valve, Swing Motor, Travel Motor |
| Electrical System | 906-970 | Electrical Schematic (DX55W) |
| Attachments | 971-994 | Boom and Arm, Bucket |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Hydraulic filter filtering grain size | 10μ (rated) or smaller | p. 737 |
| Hydraulic filter replacement interval | every 250 hours (after initial 50 hours) | p. 739 |
| Fuel filter replacement interval | every 500 hours (after initial 50 hours) | p. 342 |
| Fuel filter tightening torque | 14 - 17 ft·lb (19.6 - 23.5 N·m; 2.0 - 2.4 kgf·m) | p. 332 |
| Engine oil filter replacement interval | every 500 hours (after initial 50 hours) | p. 345 |
| Air cleaner element cleaning air pressure | 42 -71 psi (0.29 -0.49 MPa; 3.0 -5.0 kgf/cm2) | p. 337 |
| Air cleaner element replacement interval | every 500 hours | p. 342 |
| Fuel and coolant hoses replacement interval | every two years | p. 351 |
| O-rings and seals replacement recommendation | replace whenever the assembly is being overhauled or re-assemble | p. 631 |
| Travel Motor Taper roller bearings replacement criteria | replace body assembly if damaged or not smooth | p. 767 |
| Oil temperature abnormally high cause and remedy (Oil cooler clogged or air circulation to cooler blocked) | Clean | p. 608 |
| Oil temperature abnormally high cause and remedy (Cooling fan belt tension too loose) | Readjust belt tension | p. 608 |
Yanmar B55W-2 Common Problems This Manual Covers
Yanmar B55W-2 loses drive to one or both wheels, machine won't travel or pulls hard to one side
Check hydraulic fluid level first; the system holds 72 liters total. Inspect the travel motor and final drive for external leaks, then verify main hydraulic pressure meets the 230 kg/cm2 relief spec (page 73). Work through the control valve troubleshooting procedures. Replace taper roller bearings if they feel rough or show damage on teardown.
Manual Section: Hydraulic Control Valve TroubleshootingBoom, arm, and bucket functions become slow, weak, or stop responding under load p. 739
Verify hydraulic oil level; system capacity is 72 liters. Inspect the hydraulic filter and replace if past the 250-hour service interval (10μ rated element, page 739). Measure main circuit relief pressure at 230 kg/cm2. Test for internal cylinder leakage by loading each attachment at full extension and watching for unintended drift under sustained pressure.
Manual Section: Hydraulic System General TroubleshootingHydraulic system overheats and all work functions lose power after machine warms up p. 608
Inspect and clean the oil cooler core; blocked airflow is the leading cause of thermal buildup (page 608). Verify cooling fan belt tension and readjust if loose. Check hydraulic fluid level against the 72-liter system capacity, then replace the filter if past 250 hours. Low fluid and a blocked filter together will spike temps fast after warm-up.
Manual Section: Hydraulic System General TroubleshootingEngine cranks but won't fire, or starts briefly then stalls in field conditions
Check fuel level and verify the shutoff valve is fully open. Bleed air from the fuel system, then inspect both primary and secondary fuel filters; replace if past 500 hours. Torque replacement filters to 14-17 ft•lb (page 332). Verify battery voltage, confirm all safety interlocks are satisfied, and pull any stored fault codes before disassembling further.
Manual Section: Engine Compression & General TroubleshootingSwing rotation is jerky, slower than normal, or drifts when stopped on a slope
Inspect swing motor external seals for leakage and check the gearbox oil level. Verify main hydraulic pressure holds at 230 kg/cm2. Diagnose the motor, gearbox, and related control valves using the swing troubleshooting procedures starting. Replace all O-rings and seals during disassembly, as the manual requires new seals whenever any swing assembly is opened.
Manual Section: Hydraulic Swing System TroubleshootingFrequently Asked Questions
What is the torque spec for YANMAR B55W-2 wheel excavator bolts?
The manual provides detailed torque values for standard metric fasteners, U.S. fasteners, and Type 8 phosphate coated hardware. For M8 x Std. bolts, torque values vary by grade: Grade 3.6 is 0.70 kg•m (5.06 ft lb) and Grade 4.6 is 0.75 kg•m (5.42 ft lb). Refer to page 115 for the full table.
What do YANMAR B55W-2 error codes mean?
The manual provides a 'Control Failure Detection' table listing failure conditions and their corresponding 'Number of flashes' (error codes). A coolant temperature sensor failure is indicated by 4 flashes; a speed sensor failure results in 6 flashes. Refer to page 940 for the complete list of diagnostic items and their flash patterns.
What hydraulic components are covered in this service manual?
Pages 583–905 cover the full hydraulic system: troubleshooting, testing and adjustment procedures, accumulator, center joint, cylinders, main control valve, swing motor, and travel motor. Full hydraulic schematics for the B55W-2 circuit are included.
What are the hydraulic filter and fuel filter service intervals for the B55W-2?
Replace the hydraulic filter every 250 hours (after the initial 50-hour break-in service). Tighten the fuel filter to 14–17 ft·lb. Both intervals and torque specs are specified exactly as printed by Yanmar in the General Maintenance section (pages 87–126).
Can I download and print this manual?
Yes. After purchase you receive a PDF download link. The file is print-ready and can be opened on any device. All 994 pages are included with no expiry.
What format is this manual delivered in?
This manual is delivered as a searchable PDF file. It is bookmarked by section and keyword-searchable so you can jump directly to the spec or procedure you need.
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