Komatsu WA420-3MC Wheel Loader Service Manual
781 pages · Publication CEBM003502
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- Models
- WA420-3MC
- Serial coverage
- A31001 and up
- Manual type
- Service Manual
- Pages
- 781
- Publication
- CEBM003502
- Condition
- Brand new
What's inside
From the manual's own table of contents: 3 sections, 205 entries. See sample pages (PDF, 817 KB)
General5 topics
- FOREWORD
- GENERAL
- STRUCTURE AND FUNCTION
- TESTING, ADJUSTING AND TROUBLESHOOTING
- DISASSEMBLY AND ASSEMBLY
STRUCTURE AND FUNCTION51 topics
- PPC valve
- PPC relief valve
- Accumulator (for PPC valve)
- Relief valve
- Suction valve
- Main control valve operation
- Boom and bucket spool hold position
- Boom spool at lower position
- Boom spool at float position
- Bucket spool at dump position
- Bucket spool at tilt position
- Bucket
- ROPS cab
- Air conditioner
- Air conditioner piping
- Electric circuit diagram (foldout)
- Electric circuit Diagram ECSS (foldout)
- Machine monitor system
- Outline
- Main monitor
- Main monitor display function
- Trouble data display mode
- Maintenance monitor
- Maintenance monitor display function
- Transmission auto-shift control system
- System structure diagram
- Gear shift characteristics
- Safety function
- Transmission controller
- Suspension system)
- Connector signals input/output
- Sensors
- Engine oil level sensor
- Radiator water level sensors
- Engine water temperature sensor
- sensor
- Fuel level sensor
- Engine speed sensor
- Engine oil pressure sensor
- Engine starting circuit
- Combination switch
- Kick-down, hold switch
- Kick-down electric circuit diagram
- Normal operation
- Kick-down switch operated
- switch (case II)
- Transmission cut-off switch
- Electric parking brake control
- Parking brake emergency release switch
- Emergency brake switch
- Parking brake safety relay
TROUBLESHOOTING96 topics
- Points to remember when troubleshooting
- Sequence of events in troubleshooting
- Precautions when carrying out maintenance
- Points to remember when handling hydraulic equipment
- Handling connectors
- Checks before troubleshooting
- Method of using troubleshooting charts
- Connector types and mounting locations
- Connector and pin identification
- Troubleshooting of engine system (S mode)
- Troubleshooting of main monitor system (M mode)
- Troubleshooting of maintenance monitor system (K mode)
- Troubleshooting of electrical system (E mode)
- Troubleshooting of hydraulic and mechanical system (chassis related) (T mode)
- Troubleshooting of E.C.S.S. (Electronically Controlled Suspension System) (D mode)
- Troubleshooting of transmission controller system (A mode)
- Starting performance is poor
- Engine does not start
- Engine does not accelerate smoothly (poor throttle response)
- Engine stops during operations
- Engine does not rotate smoothly (hunting)
- Engine lacks output (no power)
- Exhaust is black (incomplete combustion)
- Oil consumption is excessive (or exhaust gas is blue)
- Oil becomes contaminated quickly
- Fuel consumption is excessive
- Oil is in cooling water, or water spurts back, or water level goes down
- Oil pressure lamp lights up (drop in oil pressure)
- Oil level rises
- Water temperature becomes too high
- Abnormal noise is made
- Vibration is excessive
- Trouble data display
- Main monitor does not work
- When starting switch is turned on and engine is started immediately, all lamps stay lit
- Speedometer displays does not work properly
- Abnormality in shift indicator
- (a) Stays at N even when directional lever is at F
- (b) Stays at N even when directional lever is at R
- when directional lever is at F
- when directional lever is at R
- (e) Does not display 1st, 4th
- (f) Does not display 3rd, 4th
- (g) Does not display 2nd, 3rd
- (h) Does not display 1st, 2nd
- High beam does not light up
- Turn signal display does not light up
- (a) L.H turn signal does not light up
- (b) R.H turn signal does not light up
- Abnormality in parking display
- (a) Parking lamp does not light up
- (b) Parking lamp stays lit
- Not used
- Night lighting does not light up
- Abnormality in front working lamp
- (a) Neither monitor display nor front working lamp light
- (b) Working lamp lights up but monitor display does not light up
- (c) Monitor lights up but working lamp does not light up
- Abnormality in rear working lamp
- Abnormality in transmission cut-off
- (a) When monitor switch is pressed, cut-off function is not switched and display is not given
- (b) Monitor display goes out but cut-off function stays on
- (c) Monitor display lights up but cut-off function is not actuated
- Abnormality in parking brake dragging warning
- lever is at N, and caution lamp flashes
- not light up even when directional lever is at position other than N
- continuously, or they are not actuated
- (a) Actuated continuously
- (b) Not actuated
- light up for 3 seconds, maintenance monitor does not work
- (a) All lamps on maintenance monitor do not light up for 3 seconds
- (b) Some lamps do not light
- but do not go out
- (within 3 seconds), all lamps on maintenance monitor do not go out
- K-4 When staring switch is turned ON (engine stopped), CHECK items flash
- Engine oil level display flashes
- Engine water level display flashes
- K-5 When starting switch is turned ON (engine started), CAUTION items flash
- Engine oil pressure display flashes
- Battery charge level display flashes
- Brake oil pressure display flashes
- Air cleaner display flashes
- K-6 CAUTION items are flashing but alarm buzzer does not sound
- K-7 There is no abnormality in monitor display but alarm buzzer sounds
- does not light up
- CHECK lamp
- CAUTION lamp
- CAUTION lamp) lights up
- maintenance monitor does not light up)
- K-11 Night lighting lights up even when lamp switch is OFF, night lighting stays lit
- K-12 Service meter does not work
- K-13 Service runs even when engine is stopped
- K-14 Abnormality in gauge items
- Abnormality in fuel gauge
- Abnormality in engine water temperature gauge
- Abnormality in torque converter oil temperature gauge
DISASSEMBLY AND ASSEMBLY50 topics
- TORQUE CONVERTER
- DISASSEMBLY
- ASSEMBLY
- TRANSMISSION
- TRANSMISSION CLUTCH PACK
- FORWARD, 1ST CLUTCH ASSEMBLY
- REVERSE, 2ND CLUTCH ASSEMBLY
- 3RD, 4TH CLUTCH ASSEMBLY
- PARKING BRAKE
- TRANSMISSION CONTROL VALVE
- REMOVAL
- INSTALLATION
- TRANSMISSION ACCUMULATOR VALVE
- DRIVE SHAFT
- FRONT AXLE
- REAR AXLE
- FRONT DIFFERENTIAL
- REAR DIFFERENTIAL
- DIFFERENTIAL
- FINAL DRIVE
- CENTER HINGE PIN
- STEERING VALVE (ORBIT ROLL)
- STEERING VALVE
- DISASSEMBLY OF ROTOR
- ASSEMBLY OF THE CONTROL SIDE
- ASSEMBLY OF ROTOR
- STEERING DEMAND VALVE
- STEERING, SWITCH PUMP
- STEERING CYLINDER
- BRAKE VALVE
- RIGHT BRAKE VALVE (TANDEM)
- LEFT BRAKE VALVE (SINGLE)
- BRAKE
- PARKING BRAKE DISC
- HYDRAULIC TANK
- WORK EQUIPMENT, PPC PUMP
- MAIN CONTROL VALVE
- DISASSEMBLY (2 spool valve)
- ASSEMBLY (2 spool valve)
- DISASSEMBLY (3 spool valve)
- ASSEMBLY (3 spool valve)
- BUCKET CYLINDER
- BOOM CYLINDER
- HYDRAULIC CYLINDER
- COUNTERWEIGHT
- FUEL TANK
- AIR CONDITIONER UNIT
- AIR CONDITIONER CONDENSER
- DRY RECEIVER
- AIR CONDITIONER COMPRESSOR
Inside this manual
Real pages from this service manual (781 pages). Open the sample pages (PDF, 816 KB)
- Specifications, page 34: GENERAL
- Troubleshooting, page 298: TROUBLESHOOTING
- Diagram, page 430: TROUBLESHOOTING
- Foldout diagram, page 778
Other manuals for this machine
Save 10% on 2 manuals, 15% on 3 or more. Other manuals for the WA420-3MC are listed below. Editions cover different serial number ranges: check the serial coverage and tick only the ones that match your machine.
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This is a service manual
Here's how it compares to the other manual types.
Service manual
Factory repair procedures and technical information such as specifications, troubleshooting, and wiring and hydraulic diagrams, for the models and systems the manual covers. See What's inside for its topics.
Operator's manual
Safe operation, controls, maintenance schedules, lubrication points, inspections, and basic checks. Repair procedures are in the service manual.
Parts manual
Illustrated diagrams with factory part numbers for identifying components and ordering parts. Repair procedures are in the service manual.
Engine service manuals are sometimes sold separately, since certain machine models were offered with more than one engine option.
What it's used for
Factory manual for in-house farm and construction shop use. Straightforward, complete, and easy to follow. It contains the OEM information dealership service departments and parts counters use to diagnose problems, identify components, and perform maintenance or repairs correctly.
Service shops and owner/operators who repair their own equipment
Identifying correct parts and seeing how assemblies come apart and go back together
Keeping equipment running with less downtime
Factory manual, 781 pages
Quantity one is the manual described above.
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Binder not included
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Questions about model, serial number, engine coverage or contents? Contact us before purchasing and we'll help confirm it's the right manual. Please verify the manual type, machine model, serial number range and engine coverage before purchasing: manuals ordered in error carry a 20% restocking fee (return policy).