Komatsuwheel loadersmall ( - wa120 / sk*)
Komatsu WA20-1(S/N 1001-UP)
Maintenance schedule, common problems & OEM parts breakdown
The Komatsu WA20-1 (S/N 1001-UP) is a compact/utility-class wheel loader built from 1987 to 1989, sized around 4 metric tons (3,978 kg / 8,770 lb) operating weight. It runs a Komatsu 4D94-2 naturally aspirated, mechanically governed 4-cylinder diesel rated 36.5 kW (49 hp) gross from 2.94 L displacement, paired with a TORQFLOW full-powershift countershaft transmission running two forward gears and one reverse. Standard equipment is a general-purpose bucket of about 0.6 m3 (0.79 cu yd) with bolt-on teeth and an open ROPS canopy; no enclosed cab is documented for this serial range. The 4D94-2 engine was shared with Komatsu's WA30-1 loader of the same era, putting the WA20-1 in a light-duty yard and nursery role rather than quarry or heavy civil work.
Komatsu followed the WA20-1 with the WA20-2 (S/N 10001-UP); the -2 series moved to a Yanmar-sourced 3-cylinder diesel in place of the Komatsu 4D94-2, a real powertrain break rather than a running update. Komatsu reused the WA20 badge across more than one small-loader generation, so buyers and parts counters need the serial number, not just the model name, to identify the right components. In today's used and parts market the WA20-1 survives mainly as a compact loader for nurseries, small yards, and light agricultural or estate work, valued for low operating cost and simple mechanical-diesel serviceability with no electronics to fail. Parts supply is thin for a discontinued model this old, so documented service intervals and careful preventive maintenance matter more here than on a mainstream current loader.
Below: full specifications, fluids & capacities, the factory service schedule, common service parts, verified fault codes, what owners discuss, attachment guidance, the complete assembly directory, and a serial-number reference. Complete parts lists with full OEM part numbers, exploded diagrams, quantities, and fitment data are available free in Heavy Parts AI.
Komatsu WA20-1(S/N 1001-UP) specifications
Engine
| Engine model | Komatsu 4D94 naturally aspirated diesel, 4-cylinder |
| Gross power | 36.5 kW (49 hp) |
| Net power | Not published for this serial range — verify with your dealer |
| Displacement | 2.94 L (179.5 cu in) |
| Cylinders | 4 |
| Emissions tier | Pre-emissions-regulation era; no tier certification applies to this build range |
Weights
| Operating weight | 3,978 kg (8,770 lb) |
| Shipping weight | Not documented for this exact serial range — verify with your dealer |
| Ground pressure | Not published |
Dimensions
| Transport length (bucket lowered) | 4.51 m (14.8 ft) |
| Transport width (over tires) | 1.80 m (5.9 ft) |
| Transport height (to cab top) | 2.87 m (9.4 ft) |
| Wheelbase | 2.16 m (7.1 ft) |
| Turning radius (outside) | 4.27 m (14.0 ft) |
| Ground clearance | Not documented for this exact serial range — verify with your dealer |
Performance
| Travel speed, forward | 25.1 km/h (15.6 mph) |
| Travel speed, reverse | 10.1 km/h (6.3 mph) |
| Breakout force | 30.9 kN (6,940 lb) |
| Bucket capacity | 0.6 m³ (0.79 cu yd) |
| Gradeability | Not published for this exact serial range — verify with your dealer |
Service capacities (summary)
| Fuel tank | 60.2 L (15.9 gal) |
| Cooling system | 12.1 L (3.2 gal) |
| Engine oil | Not published for this exact serial range — verify with your dealer |
| Hydraulic system | Not published for this exact serial range — verify with your dealer |
Values vary by configuration, region, and serial range — confirm against your machine before planning transport or lifts.
WA20-1(S/N 1001-UP) fluids & capacities
| System | Capacity | Recommended fluid |
|---|---|---|
| Engine crankcase (with filter) | Not documented in public sources for this exact serial range — verify with the OMM lubricant chart or a Komatsu dealer. | Komatsu genuine diesel engine oil (EO series); grade selected by ambient temperature per the OMM oil-viscosity chart, typically in the SAE 10W to SAE 30 / 10W-30 range for this engine class. |
| Cooling system | 12.1 L (3.2 US gal) | Komatsu genuine coolant (ethylene-glycol based antifreeze/summer coolant), concentration set per ambient temperature; use permanent-type antifreeze in cold climates. |
| Fuel tank | 60.2 L (15.9 US gal) | Diesel fuel meeting ASTM D975 No. 2-D grade; use No. 1-D or a winter-blend diesel in cold climates per the OMM fuel guidance. |
| Transmission / torque converter (powertrain) | Not documented in public sources for this exact serial range — verify with the OMM lubricant chart or a Komatsu dealer. | Komatsu genuine powertrain oil (TO series), or engine oil where the OMM equivalency chart allows; standard for the TORQFLOW-type transmission on this loader class. |
| Front axle / differential and final drive | Not documented in public sources for this exact serial range — verify with the OMM lubricant chart or a Komatsu dealer. | Komatsu genuine axle oil (AXO series gear oil), grade per the OMM axle lubricant chart. |
| Rear axle / differential and final drive | Not documented in public sources for this exact serial range — verify with the OMM lubricant chart or a Komatsu dealer. | Komatsu genuine axle oil (AXO series gear oil), same spec as the front axle. |
| Hydraulic system (tank and circuit) | Not documented in public sources for this exact serial range — verify with the OMM lubricant chart or a Komatsu dealer. | Komatsu genuine hydraulic oil (HO series), viscosity graded by ambient temperature per the OMM hydraulic oil chart. |
| Grease (chassis lubrication points) | Spec only — no reservoir capacity; applied at grease fittings per the OMM lubrication schedule. | Komatsu genuine multipurpose lithium-based grease, NLGI grade selected per the OMM temperature chart. |
Capacities are refill values from factory literature — always fill to the dipstick/sight gauge, not the number.
Komatsu WA20-1(S/N 1001-UP) maintenance schedule
| Service interval | Tasks |
|---|---|
| Every 50 h |
|
| Every 250 h |
|
| Every 500 h |
|
| Every 1,000 h |
|
| Every 2,000 h |
|
| Every 4,000 h |
|
Servicing the WA20-1(S/N 1001-UP) beyond the schedule
Predictive Maintenance & Fluid Analysis
With no ECM or fault codes on the mechanically governed 4D94-2, fluid sampling is the main early-warning tool on this loader. Pull engine oil samples at every oil change to track wear metals from the cast-iron block and catch coolant intrusion before it fouls the crankcase. Sample hydraulic and TORQFLOW transmission oil at major services; rising copper or bronze readings flag torque converter or clutch pack wear early. Track tire pressure and axle oil condition alongside samples for a complete trend picture on this simple mechanical machine.
Corrective & Common Repairs
Expect wear at the lift arm, bucket, and steering cylinder pin/bushing points; regreasing lapses on these small loaders show up fast as slop in the linkage. The TORQFLOW transmission's clutch packs and torque converter are the next common failure point, especially on machines worked hard in reverse-heavy yard duty. Fuel system corrective work centers on the injection pump and injectors, since the naturally aspirated diesel has no turbo or electronics to mask a tired pump. Radiator hoses perish long before the cast-iron block wears out, so replace on condition.
Overhaul & Rebuild Points
A full engine overhaul on the 4D94-2 covers cylinder liners, pistons, rings, and main/rod bearings; as a naturally aspirated mechanical engine, rebuild work stays simpler than on turbocharged, electronically governed successors. Torque converter and transmission clutch pack rebuilds follow high-hour service life, along with axle differential and final drive gear inspection at both ends. Hydraulic pump and lift/tilt cylinder reseal is typical rebuild work once cycle times slow or drift appears under load. Parts supply for this serial range is thin, so plan rebuilds around salvaged or remanufactured components.
Seasonal & Environment Servicing
Before winter, switch to a lighter engine oil grade and check coolant freeze protection; the 4D94-2 has no block heater, so cold starts depend on battery and glow plug condition. Drain water from the fuel tank and fuel/water separator regularly in humid or wet-season storage to protect the mechanical injection pump. In hot, dusty yard or field environments, clean the air cleaner dust cup more often and check the radiator fins for packed debris. Grease all pivot points before outdoor storage to keep moisture out of the open ROPS linkage.
WA20-1(S/N 1001-UP) common service parts
| Part number | Part | Notes | |
|---|---|---|---|
| YM129100-55650 | Element,Fuel Filter | Fuel system service | Check fitment → |
| 07281-00197 | Clamp,(With Pre-Fuel Filter) | Fuel system service | Check fitment → |
| 362-54-27280 | Plate? Instruction,Fuel Filter | Fuel system service | Check fitment → |
| 09637-30161 | Plate? Instruction,Air Cleaner (Single Element) | Air intake service | Check fitment → |
| 07000-02080 | O-Ring,Hydraulic Oil Filter | Hydraulic service | Check fitment → |
Always confirm against your machine's serial number — cross-check any part in Heavy Parts AI before ordering.
WA20-1(S/N 1001-UP) attachments & work tools
Loading bucket (standard/GP)
Factory-standard work tool is a general-purpose loading bucket, about 0.6 m³ heaped (0.8 cu yd) and roughly 1.9 m wide (6.3 ft), sized to the machine's track width. Shipped with bolt-on digging teeth as the standard edge; some published spec listings show a smaller capacity for this class, so confirm bucket size against the machine's data plate.
Bucket edge options
Bolt-on teeth are standard for digging and loose material. A smooth bolt-on cutting edge (teeth removed) is the common swap for grading, stockpiling, and finish loading. Edge type changes on the same bucket casting rather than requiring a separate tool.
Multi-purpose (4-in-1) bucket
A 4-in-1/multi-purpose bucket, combining a dozing blade, clamshell grapple, and loading bucket, is a typical work-tool option for utility loaders this size. It needs its own hydraulic clamp function beyond the base lift/tilt circuit, so fitment depends on an added hydraulic circuit rather than being plug-and-play.
Pallet forks
Pallet forks are the common secondary work tool for utility loaders in this class, used for palletized and unitized material handling in place of the bucket. On a machine this size, forks pin onto the standard loader linkage rather than a dedicated quick-attach frame.
Mounting / coupler system
Work tools attach via a fixed-pin bucket-to-lift-arm linkage typical of small utility loaders of this era; no hydraulic quick-coupler is documented for this model. Pin-type hydraulic quick-attach coupler systems appear later, on larger Komatsu tool-carrier wheel loaders, not this class.
Auxiliary hydraulics for attachments
The base hydraulic circuit powers only the boom lift and bucket tilt cylinders. Tools with their own function, such as a multi-purpose bucket clamp or a grapple, need an added third hydraulic circuit, which is not standard equipment on a machine this size.
Cab / guarding configuration
Documented factory configuration is an open ROPS canopy over the operator station. No enclosed-cab variant is documented specifically for this serial range; treat an enclosed cab as a dealer-fit or later-series option if required.
All WA20-1(S/N 1001-UP) assemblies by section
Every catalogued assembly group for the Komatsu WA20-1(S/N 1001-UP). Open an assembly to preview the parts inside — full OEM part numbers are available in Heavy Parts AI.
3d78-1a Engine S/N 00101-Up
Komatsu : Wa20-1(S/N 1001-Up) : 3d78-1a Engine S/N 00101-Up : Air Cleaner
| YM***41 | Buffle | 1 |
| YM***01 | Element | 1 |
| YM***21 | Body | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : 3d78-1a Engine S/N 00101-Up : Air Intake Manifold
| YM***02 | Screw | 2 |
| YM***00 | Manifold,Air Intake | 1 |
| YM***52 | Bolt | 2 |
Komatsu : Wa20-1(S/N 1001-Up) : 3d78-1a Engine S/N 00101-Up : Alternator
| YM***63 | Regulator Ass'Y | 1 |
| YM***BM | Bearing,Ball | 1 |
| YM***62 | Brush | 2 |
Komatsu : Wa20-1(S/N 1001-Up) : 3d78-1a Engine S/N 00101-Up : Alternator And Mounting
| YM***30 | Plate,Adjust | 1 |
| YM***02 | Bolt | 1 |
| YM***02 | Nut | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : 3d78-1a Engine S/N 00101-Up : Camshaft And Tappet
| YM***01 | Gear Ass'Y,Camshaft | 1 |
| YM***11 | Camshaft | 1 |
| YM***10 | Camshaft | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : 3d78-1a Engine S/N 00101-Up : Crankshaft
| YM***00 | Gear,Crank | 1 |
| YM***01 | Ball,Steel | 3 |
| YM***10 | Spring Pin | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : 3d78-1a Engine S/N 00101-Up : Cylinder Block(#00101-00765)
| YM***02 | Screw | 1 |
| YM***00 | Liner,Cylinder | 3 |
| YM***00 | O-Ring (Kit) | 2 |
Komatsu : Wa20-1(S/N 1001-Up) : 3d78-1a Engine S/N 00101-Up : Cylinder Block(#00766-)
| YM***02 | Screw | 1 |
| YM***00 | O-Ring (Kit) | 2 |
| YM***20 | Plug,Drain(Without Oil Cooler Type) | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : 3d78-1a Engine S/N 00101-Up : Cylinder Head
| YM***80 | Retainer, Spring | 6 |
| YM***40 | Seal,Valve? Exhaust (Kit) | 6 |
| YM***10 | Valve,Exhaust | 3 |
Komatsu : Wa20-1(S/N 1001-Up) : 3d78-1a Engine S/N 00101-Up : Cylinder Head Cover
| YM***20 | Cover, Breather | 1 |
| YM***51 | Cap, Lub. Oil Supply | 1 |
| YM***00 | Clip,Breather Hose | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : 3d78-1a Engine S/N 00101-Up : Exhaust Manifold
| YM***10 | Manifold, Exhaust | 1 |
| YM***02 | Nut | 4 |
| YM***22 | Stud | 4 |
Komatsu : Wa20-1(S/N 1001-Up) : 3d78-1a Engine S/N 00101-Up : Flywheel And Flywheel Housing
| YM***00 | Gear,Ring | 1 |
| YM***02 | Screw | 6 |
| YM***02 | Screw | 4 |
Komatsu : Wa20-1(S/N 1001-Up) : 3d78-1a Engine S/N 00101-Up : Front Cover And Gear
| YM***10 | Washer,Seal | 9 |
| YM***51 | Cap, Lub. Oil Supply | 1 |
| YM***52 | Bolt | 4 |
Komatsu : Wa20-1(S/N 1001-Up) : 3d78-1a Engine S/N 00101-Up : Fuel Filter(#00101-00765)
| YM***00 | O-Ring (Kit) | 1 |
| YM***70 | Lever | 1 |
| YM***80 | Cup, Strainer | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : 3d78-1a Engine S/N 00101-Up : Fuel Filter(#00766-)
| YM***00 | O-Ring (Kit) | 1 |
| YM***70 | Lever | 1 |
| YM***80 | Cup, Strainer | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : 3d78-1a Engine S/N 00101-Up : Fuel Injection Pump
| YM***70 | Retainer, Spring | 3 |
| YM***50 | Kit, Shim | 1 |
| YM***10 | Plate? Caution | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : 3d78-1a Engine S/N 00101-Up : Fuel Injection Pump And Piping
| YM***20 | Retainer, Pipe | 1 |
| YM***60 | O-Ring,Fuel Injection Pump | 1 |
| YM***80 | Screw | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : 3d78-1a Engine S/N 00101-Up : Fuel Nozzle And Spill Hose(#00101-01291)
| YM***20 | Spring | 1 |
| YM***91 | Joint | 1 |
| YM***50 | Check Valve Ass'Y | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : 3d78-1a Engine S/N 00101-Up : Fuel Nozzle And Spill Hose(#01292-)
| YM***70 | Union | 1 |
| YM***20 | Spring | 1 |
| YM***51 | Check Valve Ass'Y,Joint | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : 3d78-1a Engine S/N 00101-Up : Gasket Kit
| YM***30 | Gasket,Cylinder Head | 1 |
| YM***91 | Gasket Kit | 1 |
| YM***10 | Gasket,Flywheel Housing | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : 3d78-1a Engine S/N 00101-Up : Governor
| YM***00 | Spring, Regulator | 1 |
| YM***01 | Weight Assembly., Governor | 1 |
| YM***00 | Lever Ass'Y | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : 3d78-1a Engine S/N 00101-Up : Lubricating Oil Filter
| YM***50 | Nut | 1 |
| YM***05 | Bracket | 1 |
| YM***02 | Bolt Plated | 3 |
Komatsu : Wa20-1(S/N 1001-Up) : 3d78-1a Engine S/N 00101-Up : Lubricating Oil Pump And Suction Pipe
| YM***80 | Pipe,Inlet | 1 |
| YM***50 | Oil Pressure Transmitter | 1 |
| YM***40 | Gasket,Inlet Pipe | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : 3d78-1a Engine S/N 00101-Up : Oil Pan
| YM***52 | Screw | 6 |
| YM***02 | Screw | 18 |
| YM***52 | Screw | 2 |
Komatsu : Wa20-1(S/N 1001-Up) : 3d78-1a Engine S/N 00101-Up : Piston And Connecting Rod
| YM***00 | Screw | 2 |
| YM***80 | Piston Ass'Y | 3 |
| YM***00 | Ring,Snap | 6 |
Komatsu : Wa20-1(S/N 1001-Up) : 3d78-1a Engine S/N 00101-Up : Power Take Off
| YM***50 | Bracket | 1 |
| YM***70 | Cover,(For Shipping) | 1 |
| YM***80 | Gasket | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : 3d78-1a Engine S/N 00101-Up : Rocker Arm
| YM***02 | Screw | 6 |
| YM***80 | Spring | 3 |
| YM***00 | Plug | 2 |
Komatsu : Wa20-1(S/N 1001-Up) : 3d78-1a Engine S/N 00101-Up : Safety Relay And Thermostart Timer
| YM***20 | Timer,Thermostart | 1 |
| YM***00 | Relay,Safety | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : 3d78-1a Engine S/N 00101-Up : Starting Motor
| YM***60 | Bearing,Ball | 1 |
| YM***60 | O-Ring | 4 |
| YM***20 | Cover | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : 3d78-1a Engine S/N 00101-Up : Starting Motor And Mounting
| YM***02 | Nut | 2 |
| YM***02 | Nut,Rock | 1 |
| YM***50 | O-Ring | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : 3d78-1a Engine S/N 00101-Up : Tool
| YM***50 | Wrench,Engine Oil Filter | 1 |
| YM***20 | Flex Horn (Option.) | 1 |
| YM***60 | Fuel, Wrench, Strainer | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : 3d78-1a Engine S/N 00101-Up : Water Pump And Cooling Fan
| YM***02 | Bolt Plated | 2 |
| YM***20 | Gasket,Water Pump | 1 |
| YM***02 | Screw | 1 |
Drive Shaft? Differential And Wheels
Komatsu : Wa20-1(S/N 1001-Up) : Drive Shaft? Differential And Wheels : Axle Housing
| 01***30 | Bolt,(For Quick Shift) (Mitsubishi) | 48 |
| 01***30 | Bolt | 24 |
| 01***30 | Washer, Spring (Supplied W/Spider Assembly), Washer-Spring | 48 |
Komatsu : Wa20-1(S/N 1001-Up) : Drive Shaft? Differential And Wheels : Brake
| 01***50 | Bolt,(With Service Valve R.H.) | 3 |
| 01***70 | Bolt, Mount Bracket And Oil Inlet Tube, Bolt | 3 |
| 01***30 | Washer, Spring (Supplied W/Spider Assembly), Washer-Spring | 6 |
Komatsu : Wa20-1(S/N 1001-Up) : Drive Shaft? Differential And Wheels : Brake Pedal And Piping
| 01***16 | Bolt (With Air Heater & Conditioner) | 2 |
| 01***60 | Bolt, Mount Tube To Switch Pump | 3 |
| 01***40 | Bolt,(With Service Valve R.H.) | 2 |
Komatsu : Wa20-1(S/N 1001-Up) : Drive Shaft? Differential And Wheels : Differential
| 01***20 | Bolt,(With Auto Emergency Steering) | 38 |
| 01***65 | Bolt,R.H | 16 |
| 01***30 | Bolt,(For Quick Shift) (Mitsubishi) | 18 |
Komatsu : Wa20-1(S/N 1001-Up) : Drive Shaft? Differential And Wheels : Drive Shaft
| 01***35 | Bolt,(For Position Fixing) | 16 |
| 36***01 | Drive Shaft Ass'Y,Front | 1 |
| 36***02 | Drive Shaft Ass'Y,Front | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : Drive Shaft? Differential And Wheels : Master Cylinder
| 21***10 | Repair Kit | 1 |
| 21***80 | Master Cylinder A | 1 |
| 36***12 | Repair Kit | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : Drive Shaft? Differential And Wheels : Parking Brake Lever
| 01***55 | Bolt | 1 |
| 01***16 | Bolt (With Air Heater & Conditioner) | 2 |
| 01***25 | Bolt,Without Revolution Sensor | 2 |
Komatsu : Wa20-1(S/N 1001-Up) : Drive Shaft? Differential And Wheels : Wheel And Tire
| 36***30 | Wheel | 1 |
| 36***10 | Wheel Ass'Y,L.H | 2 |
| 36***20 | Wheel Ass'Y,R.H | 2 |
Komatsu : Wa20-1(S/N 1001-Up) : Drive Shaft? Differential And Wheels : Wheel And Tubeless Tire
| 36***30 | Wheel | 1 |
| 36***31 | Wheel | 1 |
| 36***10 | Tire,Bridgestone | 1 |
Engine Related Parts And Electrical System
Komatsu : Wa20-1(S/N 1001-Up) : Engine Related Parts And Electrical System : Accelertor Pedal And Linkage
| 01***20 | Bolt,(With Auto Emergency Steering) | 4 |
| 01***20 | Bolt,(For Quick Shift) (Mitsubishi) | 2 |
| 01***35 | Bolt,(For Quick Shift) (Mitsubishi) | 2 |
Komatsu : Wa20-1(S/N 1001-Up) : Engine Related Parts And Electrical System : Air Cleaner Connection
| 07***09 | Clamp,(See Fig. K0210-16a0) | 3 |
| 07***69 | Clamp,(Long Type) | 2 |
| 36***30 | Pipe,(For Back Hoe) | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : Engine Related Parts And Electrical System : Air Cleaner Connection (For Usa)
| 07***09 | Clamp,(See Fig. K0210-16a0) | 3 |
| 07***69 | Clamp,(Long Type) | 2 |
| 36***40 | Hose | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : Engine Related Parts And Electrical System : Back-Up Alarm
| 01***16 | Bolt (With Air Heater & Conditioner) | 1 |
| 01***20 | Bolt,(With Auto Emergency Steering) | 2 |
| 01***25 | Bolt,(For Canvas Canopy?Head Guard) | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : Engine Related Parts And Electrical System : Battery
| 01***16 | Bolt, Battery To Frame Ground Wire Attaching | 1 |
| 01***06 | Nut,(With Back-Up Alarm) (Op), Nut; Was 01580-10806 | 4 |
| 01***16 | Washer,Radio Controlled Slag Handling | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : Engine Related Parts And Electrical System : Beacon Lamp (For Cab)
| 01***16 | Bolt, Battery To Frame Ground Wire Attaching | 4 |
| 01***30 | Washer, Spring (Supplied W/Spider Assembly), Washer-Spring | 4 |
| 08***08 | Grommet,(Without Beacon Lamp) | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : Engine Related Parts And Electrical System : Electrical System (Front Line)
| 01***16 | Bolt (With Air Heater & Conditioner) | 2 |
| 01***20 | Bolt,(For Quick Shift) (Mitsubishi) | 1 |
| 01***25 | Bolt,(For Canvas Canopy?Head Guard) | 6 |
Komatsu : Wa20-1(S/N 1001-Up) : Engine Related Parts And Electrical System : Electrical System (Front Line) (For Cab)
| 01***16 | Bolt (With Air Heater & Conditioner) | 2 |
| 01***20 | Bolt,(For Quick Shift) (Mitsubishi) | 1 |
| 01***35 | Bolt,(For Quick Shift) (Mitsubishi) | 4 |
Komatsu : Wa20-1(S/N 1001-Up) : Engine Related Parts And Electrical System : Electrical System (Front Line) (For Usa)
| 01***16 | Bolt (With Air Heater & Conditioner) | 2 |
| 01***20 | Bolt,(For Quick Shift) (Mitsubishi) | 1 |
| 01***25 | Bolt,(For Canvas Canopy?Head Guard) | 6 |
Komatsu : Wa20-1(S/N 1001-Up) : Engine Related Parts And Electrical System : Electrical System (Main Line)
| 01***16 | Bolt (With Air Heater & Conditioner) | 2 |
| 01***16 | Bolt, Battery To Frame Ground Wire Attaching | 2 |
| 01***20 | Bolt,(Without Rops Guard? Canopy) | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : Engine Related Parts And Electrical System : Electrical System (Main Line) (For Cab)
| 01***16 | Bolt, Battery To Frame Ground Wire Attaching | 2 |
| 01***20 | Bolt,(Without Rops Guard? Canopy) | 1 |
| 01***08 | Screw - Holder | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : Engine Related Parts And Electrical System : Electrical System (Main Line) (For Usa)
| 01***16 | Bolt, Battery To Frame Ground Wire Attaching | 3 |
| 01***08 | Screw - Holder | 1 |
| 01***20 | Screw - Turn Signal And Parkinglight Mounting | 2 |
Komatsu : Wa20-1(S/N 1001-Up) : Engine Related Parts And Electrical System : Electrical System (Tail Lamp Line) (For Cab)
| 01***10 | Bolt,(With Auto Emergency Steering) | 2 |
| 01***16 | Bolt (With Air Heater & Conditioner) | 2 |
| 01***20 | Bolt,(With Auto Emergency Steering) | 2 |
Komatsu : Wa20-1(S/N 1001-Up) : Engine Related Parts And Electrical System : Electrical System (Tail Lamp Line) (For Usa)
| 01***16 | Bolt (With Air Heater & Conditioner) | 3 |
| 01***20 | Bolt,(With Auto Emergency Steering) | 2 |
| 01***40 | Bolt,(With Air Conditioner) | 2 |
Komatsu : Wa20-1(S/N 1001-Up) : Engine Related Parts And Electrical System : Engine And Transmission Mounting Parts
| 01***25 | Bolt,(For Canvas Canopy?Head Guard) | 8 |
| 01***30 | Bolt,(For Quick Shift) (Mitsubishi) | 6 |
| 01***30 | Bolt,(Not Used With Emergency Str.) | 4 |
Komatsu : Wa20-1(S/N 1001-Up) : Engine Related Parts And Electrical System : Exhaust Connection And Muffler
| 01***30 | Bolt,(For Mechanical Governor) | 2 |
| 01***16 | Bolt, Battery To Frame Ground Wire Attaching | 2 |
| 01***08 | Nut,(For Canvas Canopy?Head Guard) | 4 |
Komatsu : Wa20-1(S/N 1001-Up) : Engine Related Parts And Electrical System : Exhaust Connection And Muffler (For Usa)
| 07***49 | Clamp, Hose | 2 |
| 09***08 | Insulator | 1 |
| 36***30 | Tube | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : Engine Related Parts And Electrical System : Fuel Control Lever (For Back Hoe)
| 01***30 | Bolt,(For Mechanical Governor) | 1 |
| 01***20 | Bolt,(For Quick Shift) (Mitsubishi) | 2 |
| 01***30 | Bolt,Stopper | 2 |
Komatsu : Wa20-1(S/N 1001-Up) : Engine Related Parts And Electrical System : Fuel Tank
| 01***16 | Bolt, Battery To Frame Ground Wire Attaching | 3 |
| 01***20 | Bolt,(For Quick Shift) (Mitsubishi) | 3 |
| 01***30 | Bolt,(Not Used With Emergency Str.) | 4 |
Komatsu : Wa20-1(S/N 1001-Up) : Engine Related Parts And Electrical System : Fuel Tank (For Usa)
| 01***16 | Bolt, Battery To Frame Ground Wire Attaching | 3 |
| 01***20 | Bolt,(For Quick Shift) (Mitsubishi) | 3 |
| 01***30 | Bolt,(Not Used With Emergency Str.) | 4 |
Komatsu : Wa20-1(S/N 1001-Up) : Engine Related Parts And Electrical System : Instrument Panel
| 01***10 | Screw,(For Lighter) | 9 |
| 01***10 | Screw,R.H. Door | 4 |
| 01***05 | Washer,(Without Window Washer) | 9 |
Komatsu : Wa20-1(S/N 1001-Up) : Engine Related Parts And Electrical System : Instrument Panel (For Cab)
| 01***10 | Screw,(For Lighter) | 9 |
| 01***10 | Screw,R.H. Door | 4 |
| 01***05 | Washer,(Without Window Washer) | 9 |
Komatsu : Wa20-1(S/N 1001-Up) : Engine Related Parts And Electrical System : Instrument Panel (For Usa)
| 01***10 | Screw,R.H. Door | 13 |
| 01***05 | Washer,(Without Window Washer) | 13 |
| 08***00 | Fuse? 5a,(Mk-Ful-5) | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : Engine Related Parts And Electrical System : Radiator
| 01***12 | Bolt, Bolt,(No Need To Quick Shift) | 4 |
| 01***20 | Bolt,(Without Maintenance Monitor) | 2 |
| 01***12 | Bolt,(With Cylinder Cover) | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : Engine Related Parts And Electrical System : Radiator (For Usa)
| 01***12 | Bolt, Bolt,(No Need To Quick Shift) | 4 |
| 01***20 | Bolt,(Without Maintenance Monitor) | 2 |
| 01***12 | Bolt,(With Cylinder Cover) | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : Engine Related Parts And Electrical System : Rear Lamp
| 01***85 | Bolt,(For 2nd Travel Speed) (Op) | 2 |
| 01***30 | Washer, Spring (Supplied W/Spider Assembly), Washer-Spring | 2 |
| 08***00 | Terminal - At Rear Wiper, Cab Dome Light, Cab | 1 |
Frame And Guard
Komatsu : Wa20-1(S/N 1001-Up) : Frame And Guard : Canopy (For Back Hoe)(#1001-1344)
| 01***25 | Bolt,(For Canvas Canopy?Head Guard) | 16 |
| 01***30 | Washer, Spring (Supplied W/Spider Assembly), Washer-Spring | 16 |
| 01***32 | Washer,(With Auto Emergency Steering) | 8 |
Komatsu : Wa20-1(S/N 1001-Up) : Frame And Guard : Canopy (For Back Hoe)(#1345-)
| 01***25 | Bolt,(For Canvas Canopy?Head Guard) | 16 |
| 01***30 | Washer, Spring (Supplied W/Spider Assembly), Washer-Spring | 16 |
| 01***32 | Washer,(With Auto Emergency Steering) | 8 |
Komatsu : Wa20-1(S/N 1001-Up) : Frame And Guard : Canopy (Low Height Type)(#1001-1344)
| 01***25 | Bolt,(For Canvas Canopy?Head Guard) | 16 |
| 01***20 | Screw | 8 |
| 01***30 | Washer, Spring (Supplied W/Spider Assembly), Washer-Spring | 16 |
Komatsu : Wa20-1(S/N 1001-Up) : Frame And Guard : Canopy (Low Height Type)(#1345-)
| 01***25 | Bolt,(For Canvas Canopy?Head Guard) | 16 |
| 01***20 | Screw | 8 |
| 01***30 | Washer, Spring (Supplied W/Spider Assembly), Washer-Spring | 16 |
Komatsu : Wa20-1(S/N 1001-Up) : Frame And Guard : Canopy(#1001-1344)
| 01***25 | Bolt,(For Canvas Canopy?Head Guard) | 16 |
| 01***30 | Washer, Spring (Supplied W/Spider Assembly), Washer-Spring | 16 |
| 01***32 | Washer,(With Auto Emergency Steering) | 8 |
Komatsu : Wa20-1(S/N 1001-Up) : Frame And Guard : Canopy(#1345-)
| 01***25 | Bolt,(For Canvas Canopy?Head Guard) | 16 |
| 01***30 | Washer, Spring (Supplied W/Spider Assembly), Washer-Spring | 16 |
| 01***32 | Washer,(With Auto Emergency Steering) | 8 |
Komatsu : Wa20-1(S/N 1001-Up) : Frame And Guard : Car Heater And Piping (For Cab)
| 01***12 | Bolt,(With Cylinder Cover) | 2 |
| 01***20 | Bolt,(With Auto Emergency Steering) | 3 |
| 01***10 | Screw,(For Wiper Switch Earth) | 2 |
Komatsu : Wa20-1(S/N 1001-Up) : Frame And Guard : Counter Weight (For Utility Fork? With Grapple)
| 01***65 | Bolt,(With Canvas Or Rops Canopy) | 4 |
| 01***80 | Bolt,(For 100kg) | 4 |
| 01***45 | Washer,(For Travel Motor) (Not Show) | 4 |
Komatsu : Wa20-1(S/N 1001-Up) : Frame And Guard : Dashboard And Floor Plate
| 01***16 | Bolt, Battery To Frame Ground Wire Attaching | 8 |
| 01***20 | Bolt,(For Quick Shift) (Mitsubishi) | 6 |
| 01***50 | Bolt,(For Strengthened Cover) | 4 |
Komatsu : Wa20-1(S/N 1001-Up) : Frame And Guard : Dashboard And Floor Plate (For Cab)
| 01***16 | Bolt, Battery To Frame Ground Wire Attaching | 7 |
| 01***50 | Bolt,(For Strengthened Cover) | 4 |
| 01***10 | Screw,(For Lighter) | 4 |
Komatsu : Wa20-1(S/N 1001-Up) : Frame And Guard : Dashboard And Floor Plate (For Usa)
| 01***16 | Bolt, Battery To Frame Ground Wire Attaching | 8 |
| 01***20 | Bolt,(For Quick Shift) (Mitsubishi) | 7 |
| 01***50 | Bolt,(For Strengthened Cover) | 4 |
Komatsu : Wa20-1(S/N 1001-Up) : Frame And Guard : Floor Frame And Compartment (For Cab)(#1001-2273)
| 01***16 | Bolt, Battery To Frame Ground Wire Attaching | 4 |
| 01***20 | Bolt,(For Quick Shift) (Mitsubishi) | 8 |
| 01***30 | Bolt,(Not Used With Emergency Str.) | 8 |
Komatsu : Wa20-1(S/N 1001-Up) : Frame And Guard : Floor Frame And Compartment (For Cab)(#2274-)
| 01***16 | Bolt, Battery To Frame Ground Wire Attaching | 1 |
| 01***20 | Bolt,(For Quick Shift) (Mitsubishi) | 12 |
| 01***30 | Bolt,(Not Used With Emergency Str.) | 8 |
Komatsu : Wa20-1(S/N 1001-Up) : Frame And Guard : Floor Frame And Compartment (For Usa)(#1001-2273)
| 01***30 | Bolt,(For Mechanical Governor) | 2 |
| 01***16 | Bolt, Battery To Frame Ground Wire Attaching | 4 |
| 01***20 | Bolt,(For Quick Shift) (Mitsubishi) | 10 |
Komatsu : Wa20-1(S/N 1001-Up) : Frame And Guard : Floor Frame And Compartment (For Usa)(#2274-)
| 01***30 | Bolt,(For Mechanical Governor) | 2 |
| 01***16 | Bolt, Battery To Frame Ground Wire Attaching | 1 |
| 01***20 | Bolt,(For Quick Shift) (Mitsubishi) | 10 |
Komatsu : Wa20-1(S/N 1001-Up) : Frame And Guard : Floor Frame And Compartment(#1001-2273)
| 01***16 | Bolt, Battery To Frame Ground Wire Attaching | 4 |
| 01***20 | Bolt,(For Quick Shift) (Mitsubishi) | 10 |
| 01***20 | Bolt,(Without Rops Guard? Canopy) | 4 |
Komatsu : Wa20-1(S/N 1001-Up) : Frame And Guard : Floor Frame And Compartment(#2274-)
| 01***16 | Bolt, Battery To Frame Ground Wire Attaching | 1 |
| 01***20 | Bolt,(For Quick Shift) (Mitsubishi) | 14 |
| 01***20 | Bolt,(Without Rops Guard? Canopy) | 4 |
Komatsu : Wa20-1(S/N 1001-Up) : Frame And Guard : Front And Rear Frame
| 01***20 | Bolt,(For Quick Shift) (Mitsubishi) | 10 |
| 01***35 | Bolt, Bolt, Mount Tubes To Switch And Work Pumps | 4 |
| 01***70 | Bolt,(With Wear Guard) | 3 |
Komatsu : Wa20-1(S/N 1001-Up) : Frame And Guard : Front Frame And Counter Weight (For Livestock Raising)
| 01***20 | Bolt,(For Quick Shift) (Mitsubishi) | 2 |
| 01***45 | Bolt,(For Power Tilt Mech Angle) | 2 |
| 01***32 | Washer,(With Auto Emergency Steering) | 4 |
Komatsu : Wa20-1(S/N 1001-Up) : Frame And Guard : Operator'S Cab (1/4) (Cab And Front Window)
| 01***20 | Bolt,(With Auto Emergency Steering) | 4 |
| 01***10 | Screw,(For Lighter) | 2 |
| 01***08 | Screw - Holder | 10 |
Komatsu : Wa20-1(S/N 1001-Up) : Frame And Guard : Operator'S Cab (2/4) (Door)
| 01***25 | Bolt,(For Canvas Canopy?Head Guard) | 12 |
| 01***08 | Screw - Holder | 12 |
| 01***12 | Screw,(Additional Sun Visor) | 4 |
Komatsu : Wa20-1(S/N 1001-Up) : Frame And Guard : Operator'S Cab (3/4) (Rear Window)
| 01***12 | Bolt, Bolt,(No Need To Quick Shift) | 2 |
| 01***20 | Bolt,(With Auto Emergency Steering) | 4 |
| 01***20 | Bolt,(For Quick Shift) (Mitsubishi) | 6 |
Komatsu : Wa20-1(S/N 1001-Up) : Frame And Guard : Operator'S Cab (4/4) (Floor Mat And Cover)
| 01***12 | Bolt,(With Cylinder Cover) | 8 |
| 01***25 | Washer,Spring?For Additional Rear Lam | 8 |
| 36***90 | Mat | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : Frame And Guard : Operator'S Cab Mounting Parts
| 01***16 | Bolt, Mount Washer Tank To Bracket, Bolt | 3 |
| 01***30 | Bolt,(For Quick Shift) (Mitsubishi) | 8 |
| 01***10 | Nut,(Without Air Conditioner) | 12 |
Komatsu : Wa20-1(S/N 1001-Up) : Frame And Guard : Operator'S Seat (For Usa)(#1001-2273)
| 01***20 | Bolt,(For Quick Shift) (Mitsubishi) | 8 |
| 01***30 | Bolt,(Not Used With Emergency Str.) | 2 |
| 01***10 | Nut,(Without Air Conditioner) | 4 |
Komatsu : Wa20-1(S/N 1001-Up) : Frame And Guard : Operator'S Seat (For Usa)(#2274-)
| 01***20 | Bolt,(With Auto Emergency Steering) | 4 |
| 01***25 | Bolt,Without Revolution Sensor | 8 |
| 01***30 | Bolt,(Not Used With Emergency Str.) | 2 |
Komatsu : Wa20-1(S/N 1001-Up) : Frame And Guard : Operator'S Seat(#1001-2273)
| 01***20 | Bolt,(For Quick Shift) (Mitsubishi) | 8 |
| 01***10 | Nut,(Without Air Conditioner) | 4 |
| 01***30 | Washer, Spring (Supplied W/Spider Assembly), Washer-Spring | 8 |
Komatsu : Wa20-1(S/N 1001-Up) : Frame And Guard : Operator'S Seat(#2274-)
| 01***20 | Bolt,(With Auto Emergency Steering) | 4 |
| 01***25 | Bolt,Without Revolution Sensor | 8 |
| 01***06 | Nut,(With Back-Up Alarm) (Op), Nut; Was 01580-10806 | 4 |
Komatsu : Wa20-1(S/N 1001-Up) : Frame And Guard : Rear Cover And Engine Cover
| 01***16 | Bolt, Battery To Frame Ground Wire Attaching | 14 |
| 01***20 | Bolt,(For Quick Shift) (Mitsubishi) | 7 |
| 01***25 | Bolt,(Without Rops Guard? Canopy) | 4 |
Komatsu : Wa20-1(S/N 1001-Up) : Frame And Guard : Rear Cover And Engine Cover (For Cab)
| 01***16 | Bolt (With Air Heater & Conditioner) | 3 |
| 01***16 | Bolt, Battery To Frame Ground Wire Attaching | 14 |
| 01***20 | Bolt,(For Quick Shift) (Mitsubishi) | 7 |
Komatsu : Wa20-1(S/N 1001-Up) : Frame And Guard : Rear Cover And Engine Cover (For Usa)
| 01***16 | Bolt, Battery To Frame Ground Wire Attaching | 14 |
| 01***20 | Bolt,(For Quick Shift) (Mitsubishi) | 7 |
| 01***25 | Bolt,(For Canvas Canopy?Head Guard) | 4 |
Komatsu : Wa20-1(S/N 1001-Up) : Frame And Guard : Rear Guard
| 01***10 | Bolt (Itl) | 4 |
| 01***60 | Flat Washer - M20 (Hardened) | 4 |
| 36***40 | Block | 2 |
Komatsu : Wa20-1(S/N 1001-Up) : Frame And Guard : Rops Canopy (For Usa)
| 01***40 | Bolt,(With Center Guard) | 14 |
| 01***45 | Washer,(For Travel Motor) (Not Show) | 14 |
| 36***10 | Guard | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : Frame And Guard : Rops Canopy (Low Height Type) (For Usa)
| 01***45 | Bolt,(For Travel Motor) (Not Show) | 28 |
| 01***45 | Washer,(For Travel Motor) (Not Show) | 28 |
| 36***10 | Guard | 1 |
Mark Plate? Tool And Kit
Komatsu : Wa20-1(S/N 1001-Up) : Mark Plate? Tool And Kit : Marks And Plates (English)(#1001-2273)
| 04***60 | Screw,Machine Model (For Ec Reg.) | 8 |
| 09***35 | Plate? Name,(Limited Supply) (English) | 2 |
| 09***61 | Plate? Instruction,Air Cleaner (Single Element) | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : Mark Plate? Tool And Kit : Marks And Plates (English)(#2274-)
| 04***60 | Screw,Machine Model (For Ec Reg.) | 8 |
| 09***35 | Plate? Name,(Limited Supply) (English) | 2 |
| 09***61 | Plate? Instruction,Air Cleaner (Single Element) | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : Mark Plate? Tool And Kit : Spare Parts (Except Japan)
| 07***00 | O-Ring,(For Dual Water Pump) | 1 |
| 07***20 | O-Ring,(F5350-67a0 -17 ) | 1 |
| 07***34 | O-Ring, O-Ring,Drain Plug? R.H. Half Tank | 6 |
Komatsu : Wa20-1(S/N 1001-Up) : Mark Plate? Tool And Kit : Tool (Except Japan)
| 07***95 | Tube,Brake Oil | 1 |
| 07***60 | Tube,Rear Axle Oil | 1 |
| 07***50 | Pump, (Bellows Type) | 1 |
Steering And Control System
Komatsu : Wa20-1(S/N 1001-Up) : Steering And Control System : Steering Cylinder
| 01***20 | Bolt,(With Auto Emergency Steering) | 1 |
| 01***25 | Washer,Spring?For Additional Rear Lam | 1 |
| 07***48 | O-Ring,(F4350-64a0 -21 ) | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : Steering And Control System : Steering Oil Piping (1/2)
| 01***45 | Screw | 4 |
| 01***16 | Bolt, Battery To Frame Ground Wire Attaching | 1 |
| 01***30 | Bolt,(For Quick Shift) (Mitsubishi) | 6 |
Komatsu : Wa20-1(S/N 1001-Up) : Steering And Control System : Steering Oil Piping (2/2)
| 01***40 | Bolt, Mount Master Brake Cylinder | 4 |
| 01***30 | Washer, Spring (Supplied W/Spider Assembly), Washer-Spring | 4 |
| 07***04 | Hose,See Fig. K4010-05a0 | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : Steering And Control System : Steering Pump
| 01***55 | Screw | 4 |
| 01***30 | Washer, Spring (Supplied W/Spider Assembly), Washer-Spring | 4 |
| 04***15 | Ring, Snap | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : Steering And Control System : Steering Wheel And Column
| 01***25 | Bolt,(For Canvas Canopy?Head Guard) | 4 |
| 01***10 | Nut,(Fig.F2820-01a3-12) | 1 |
| 01***30 | Washer, Spring (Supplied W/Spider Assembly), Washer-Spring | 4 |
Transmission
Komatsu : Wa20-1(S/N 1001-Up) : Transmission : Inching Pedal
| 01***20 | Bolt,(For Quick Shift) (Mitsubishi) | 2 |
| 01***06 | Nut,(With Back-Up Alarm) (Op), Nut; Was 01580-10806 | 1 |
| 01***08 | Nut,(For Canvas Canopy?Head Guard) | 2 |
Komatsu : Wa20-1(S/N 1001-Up) : Transmission : Transfer
| 01***25 | Bolt,(For Canvas Canopy?Head Guard) | 4 |
| 01***70 | Bolt | 1 |
| 01***50 | Bolt | 2 |
Komatsu : Wa20-1(S/N 1001-Up) : Transmission : Transmission (1st And 2nd Housing)
| 01***30 | Bolt,(For Mechanical Governor) | 5 |
| 01***45 | Screw | 10 |
| 01***23 | Washer, Wiring Harness Mounting Bracket | 15 |
Komatsu : Wa20-1(S/N 1001-Up) : Transmission : Transmission (Forward And 3rd Housing)
| 04***12 | Pin, Spring | 6 |
| 07***55 | Ring,Seal | 2 |
| 11***90 | Pin,(D=10.0? L= 35.0) | 2 |
Komatsu : Wa20-1(S/N 1001-Up) : Transmission : Transmission (Reverse Housing)
| 01***30 | Bolt,(For Quick Shift) (Mitsubishi) | 6 |
| 01***32 | Washer,(With Auto Emergency Steering) | 6 |
| 04***20 | Pin,Dowel (Welded) | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : Transmission : Transmission Case
| 01***16 | Bolt (With Air Heater & Conditioner) | 1 |
| 01***20 | Bolt,(For Quick Shift) (Mitsubishi) | 1 |
| 01***30 | Bolt,(For Quick Shift) (Mitsubishi) | 14 |
Komatsu : Wa20-1(S/N 1001-Up) : Transmission : Transmission Control Lever
| 01***20 | Bolt,(With Auto Emergency Steering) | 1 |
| 01***30 | Bolt,(For Mechanical Governor) | 5 |
| 01***25 | Bolt,(For Canvas Canopy?Head Guard) | 4 |
Komatsu : Wa20-1(S/N 1001-Up) : Transmission : Transmission Control Valve (Modulation Valve)
| 01***20 | Bolt,(With Auto Emergency Steering) | 4 |
| 01***30 | Bolt,(For Mechanical Governor) | 15 |
| 01***35 | Bolt,(For Position Fixing) | 2 |
Komatsu : Wa20-1(S/N 1001-Up) : Transmission : Transmission Control Valve (Selector And Inching Valve)
| 01***25 | Bolt,Without Revolution Sensor | 2 |
| 01***65 | Bolt,R.H | 5 |
| 01***80 | Bolt,(For Long Lever Control) | 3 |
Komatsu : Wa20-1(S/N 1001-Up) : Transmission : Transmission Lock Lever
| 01***16 | Bolt (With Air Heater & Conditioner) | 4 |
| 01***25 | Bolt,(For Canvas Canopy?Head Guard) | 2 |
| 01***30 | Washer, Spring (Supplied W/Spider Assembly), Washer-Spring | 2 |
Komatsu : Wa20-1(S/N 1001-Up) : Transmission : Transmission Oil Piping
| 01***25 | Bolt,Without Revolution Sensor | 1 |
| 01***16 | Bolt, Battery To Frame Ground Wire Attaching | 3 |
| 01***25 | Bolt,(For Canvas Canopy?Head Guard) | 2 |
Komatsu : Wa20-1(S/N 1001-Up) : Transmission : Transmission Pump
| 01***90 | Bolt, Priority Valve Mounting | 6 |
| 01***25 | Washer,Spring?For Additional Rear Lam | 6 |
| 07***80 | O-Ring,Hydraulic Oil Filter | 1 |
Work Equipment
Komatsu : Wa20-1(S/N 1001-Up) : Work Equipment : Blade (For Multi Coupler And Old Pin Type)
| 04***60 | Screw,Machine Model (For Ec Reg.) | 4 |
| 09***35 | Plate? Name,(Limited Supply) (English) | 1 |
| 36***70 | Boss (Welded) | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : Work Equipment : Blade (For New Pin Type)
| 04***60 | Screw,Machine Model (For Ec Reg.) | 4 |
| 09***35 | Plate? Name,(Limited Supply) (English) | 1 |
| 36***70 | Boss (Welded) | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : Work Equipment : Bucket And Front Attachment Mounting Parts (Pin Type)
| 01***30 | Bolt,(For Quick Shift) (Mitsubishi) | 4 |
| 01***35 | Bolt,(For Quick Shift) (Mitsubishi) | 4 |
| 01***85 | Bolt,(For 2nd Travel Speed) (Op) | 4 |
Komatsu : Wa20-1(S/N 1001-Up) : Work Equipment : Bucket Cylinder (For Multipurpose Bucket)
| 07***60 | O-Ring,(F4350-59a0 -6 ) | 1 |
| 07***60 | Ring,Back-Up? Cylinder Head | 1 |
| 07***02 | Bushing | 2 |
Komatsu : Wa20-1(S/N 1001-Up) : Work Equipment : Bucket Tooth
| 02***55 | Bolt (Only For Bucket With Cutting Edge) | 12 |
| 09***14 | Nut | 12 |
| 10***11 | Tooth (Op) | 6 |
Komatsu : Wa20-1(S/N 1001-Up) : Work Equipment : Bucket? 0.26m3 (For Bolt On Cutting Edge And Tooth) (For New Pin Type)
| 04***60 | Screw,Machine Model (For Ec Reg.) | 4 |
| 09***35 | Plate? Name,(Limited Supply) (English) | 1 |
| 36***70 | Boss (Welded) | 3 |
Komatsu : Wa20-1(S/N 1001-Up) : Work Equipment : Bucket? 0.26m3 (For Multi Coupler And Old Pin Type)
| 04***60 | Screw,Machine Model (For Ec Reg.) | 4 |
| 09***35 | Plate? Name,(Limited Supply) (English) | 1 |
| 36***60 | Edge (Welded) | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : Work Equipment : Bucket? 0.26m3 (For New Pin Type)
| 04***60 | Screw,Machine Model (For Ec Reg.) | 4 |
| 09***35 | Plate? Name,(Limited Supply) (English) | 1 |
| 36***20 | Bucket | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : Work Equipment : Clam Cylinder (For Grapple)
| 07***60 | O-Ring,(F4350-59a0 -6 ) | 1 |
| 07***60 | Ring,Back-Up? Cylinder Head | 1 |
| 07***02 | Bushing | 2 |
Komatsu : Wa20-1(S/N 1001-Up) : Work Equipment : Cutting Edge? 1350mm Wide (For 0.26m3 And 0.35mm3 Bucket)
| 02***45 | Bolt | 6 |
| 09***14 | Nut | 6 |
| 36***40 | Edge,Cutting | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : Work Equipment : Cutting Edge? 1446mm Wide (For 0.5m3 Bucket)
| 02***40 | Bolt | 6 |
| 09***14 | Nut | 6 |
| 36***50 | Edge,Cutting | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : Work Equipment : Dumping Fork (For Multi Coupler And Old Pin Type)
| 04***60 | Screw,Machine Model (For Ec Reg.) | 4 |
| 09***35 | Plate? Name,(Limited Supply) (English) | 1 |
| 36***70 | Boss (Welded) | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : Work Equipment : Dumping Fork (For New Pin Type)
| 04***60 | Screw,Machine Model (For Ec Reg.) | 4 |
| 09***35 | Plate? Name,(Limited Supply) (English) | 1 |
| 36***70 | Boss (Welded) | 3 |
Komatsu : Wa20-1(S/N 1001-Up) : Work Equipment : High Lift Arm
| 01***25 | Bolt,(For Canvas Canopy?Head Guard) | 20 |
| 01***30 | Washer, Spring (Supplied W/Spider Assembly), Washer-Spring | 20 |
| 07***00 | Fitting, Grease - Upper Hinge Pin | 11 |
Komatsu : Wa20-1(S/N 1001-Up) : Work Equipment : High Lift Arm (For Livestock Raising)
| 01***25 | Bolt,(For Canvas Canopy?Head Guard) | 20 |
| 01***30 | Washer, Spring (Supplied W/Spider Assembly), Washer-Spring | 20 |
| 07***00 | Fitting, Grease - Upper Hinge Pin | 11 |
Komatsu : Wa20-1(S/N 1001-Up) : Work Equipment : Hydraulic Piping (Multipurpose Bucket Line) (For New Pin Type)
| 01***30 | Bolt,(For Quick Shift) (Mitsubishi) | 2 |
| 01***30 | Washer, Spring (Supplied W/Spider Assembly), Washer-Spring | 2 |
| 07***23 | O-Ring,(For 2nd Travel Speed) (Op) | 4 |
Komatsu : Wa20-1(S/N 1001-Up) : Work Equipment : Hydraulic Piping (Multipurpose Bucket Line) (For Multi Coupler And Old Pin Type)
| 01***30 | Bolt,(For Quick Shift) (Mitsubishi) | 2 |
| 01***30 | Washer, Spring (Supplied W/Spider Assembly), Washer-Spring | 2 |
| 07***23 | O-Ring,(For 2nd Travel Speed) (Op) | 4 |
Komatsu : Wa20-1(S/N 1001-Up) : Work Equipment : Large Capacity Bucket? 0.35m3 (For Multi Coupler And Old Pin Type)
| 04***60 | Screw,Machine Model (For Ec Reg.) | 4 |
| 09***35 | Plate? Name,(Limited Supply) (English) | 1 |
| 36***70 | Boss (Welded) | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : Work Equipment : Large Capacity Bucket? 0.35m3 (For New Pin Type)
| 04***60 | Screw,Machine Model (For Ec Reg.) | 4 |
| 09***35 | Plate? Name,(Limited Supply) (English) | 1 |
| 36***70 | Boss (Welded) | 3 |
Komatsu : Wa20-1(S/N 1001-Up) : Work Equipment : Large Capacity Bucket? 0.5m3 (For Multi Coupler And Old Pin Type)
| 04***60 | Screw,Machine Model (For Ec Reg.) | 4 |
| 09***35 | Plate? Name,(Limited Supply) (English) | 1 |
| 36***70 | Boss (Welded) | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : Work Equipment : Large Capacity Bucket? 0.5m3 (For New Pin Type)
| 04***60 | Screw,Machine Model (For Ec Reg.) | 4 |
| 09***35 | Plate? Name,(Limited Supply) (English) | 1 |
| 36***70 | Boss (Welded) | 3 |
Komatsu : Wa20-1(S/N 1001-Up) : Work Equipment : Lift Arm
| 01***25 | Bolt,(For Canvas Canopy?Head Guard) | 20 |
| 01***25 | Bolt,(Without Rops Guard? Canopy) | 2 |
| 01***30 | Washer, Spring (Supplied W/Spider Assembly), Washer-Spring | 20 |
Komatsu : Wa20-1(S/N 1001-Up) : Work Equipment : Lumber Fork (For Multi Coupler And Old Pin Type)
| 01***25 | Bolt,(For Canvas Canopy?Head Guard) | 8 |
| 01***30 | Washer, Spring (Supplied W/Spider Assembly), Washer-Spring | 8 |
| 04***24 | Pin, Spring | 2 |
Komatsu : Wa20-1(S/N 1001-Up) : Work Equipment : Lumber Fork (For New Pin Type)
| 01***25 | Bolt,(For Canvas Canopy?Head Guard) | 8 |
| 01***30 | Washer, Spring (Supplied W/Spider Assembly), Washer-Spring | 8 |
| 04***24 | Pin, Spring | 2 |
Komatsu : Wa20-1(S/N 1001-Up) : Work Equipment : Multi Coupler
| 01***20 | Bolt,(For Quick Shift) (Mitsubishi) | 4 |
| 01***30 | Bolt,(For Quick Shift) (Mitsubishi) | 4 |
| 01***65 | Bolt,(Except Japan) | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : Work Equipment : Multipurpose Bucket (For Multi Coupler And Old Pin Type)
| 01***20 | Bolt,(For Quick Shift) (Mitsubishi) | 8 |
| 01***25 | Bolt,(Without Rops Guard? Canopy) | 4 |
| 01***30 | Washer, Spring (Supplied W/Spider Assembly), Washer-Spring | 8 |
Komatsu : Wa20-1(S/N 1001-Up) : Work Equipment : Multipurpose Bucket (For New Pin Type)
| 01***20 | Bolt,(For Quick Shift) (Mitsubishi) | 8 |
| 01***25 | Bolt,(Without Rops Guard? Canopy) | 4 |
| 01***30 | Washer, Spring (Supplied W/Spider Assembly), Washer-Spring | 8 |
Komatsu : Wa20-1(S/N 1001-Up) : Work Equipment : Utility Fork (For Multi Coupler And Old Pin Type)
| 01***16 | Nut - M20 | 13 |
| 01***60 | Flat Washer - M20 (Hardened) | 13 |
| 04***60 | Screw,Machine Model (For Ec Reg.) | 4 |
Komatsu : Wa20-1(S/N 1001-Up) : Work Equipment : Utility Fork (For New Pin Type)
| 01***16 | Nut - M20 | 13 |
| 01***60 | Flat Washer - M20 (Hardened) | 13 |
| 04***60 | Screw,Machine Model (For Ec Reg.) | 4 |
Komatsu : Wa20-1(S/N 1001-Up) : Work Equipment : Utility Fork Grapple
| 01***16 | Bolt, Battery To Frame Ground Wire Attaching | 2 |
| 01***35 | Bolt,(For Quick Shift) (Mitsubishi) | 4 |
| 01***30 | Bolt,(Not Used With Emergency Str.) | 8 |
Work Equipment Control System
Komatsu : Wa20-1(S/N 1001-Up) : Work Equipment Control System : 2-Spool Control Valve (1/2)
| 01***10 | Bolt | 2 |
| 01***16 | Bolt (Op) | 2 |
| 01***20 | Bolt (Itl) | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : Work Equipment Control System : 2-Spool Control Valve (2/2)
| 01***08 | Nut (Op) | 1 |
| 07***11 | O-Ring (Kit) | 1 |
| 07***34 | O-Ring,(Not Used When (B) Spec.) | 2 |
Komatsu : Wa20-1(S/N 1001-Up) : Work Equipment Control System : 3-Spool Control Valve (1/2)
| 01***10 | Bolt | 4 |
| 01***16 | Bolt (Op) | 4 |
| 01***20 | Bolt (Itl) | 2 |
Komatsu : Wa20-1(S/N 1001-Up) : Work Equipment Control System : 3-Spool Control Valve (2/2)
| 01***08 | Nut (Op) | 1 |
| 07***11 | O-Ring (Kit) | 1 |
| 07***34 | O-Ring,(Not Used When (B) Spec.) | 2 |
Komatsu : Wa20-1(S/N 1001-Up) : Work Equipment Control System : Bucket Control Lever
| 01***16 | Bolt (With Air Heater & Conditioner) | 2 |
| 01***20 | Bolt,(With Auto Emergency Steering) | 5 |
| 01***12 | Screw | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : Work Equipment Control System : Dump Cylinder
| 01***20 | Bolt,(For Quick Shift) (Mitsubishi) | 2 |
| 01***30 | Washer, Spring (Supplied W/Spider Assembly), Washer-Spring | 2 |
| 07***60 | O-Ring,(For Pc750?800?1800) (A2610) | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : Work Equipment Control System : Front Attachment Control Lever
| 01***20 | Bolt,(For Quick Shift) (Mitsubishi) | 2 |
| 01***12 | Screw | 1 |
| 01***30 | Washer, Spring (Supplied W/Spider Assembly), Washer-Spring | 2 |
Komatsu : Wa20-1(S/N 1001-Up) : Work Equipment Control System : Hydraulic Filter
| 01***20 | Bolt,(For Quick Shift) (Mitsubishi) | 2 |
| 01***32 | Washer,(With Auto Emergency Steering) | 2 |
| 07***34 | O-Ring,(For Front Attachment) | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : Work Equipment Control System : Hydraulic Piping (1/2) (Front Attachment Line)
| 01***20 | Bolt,(For Quick Shift) (Mitsubishi) | 2 |
| 01***30 | Washer, Spring (Supplied W/Spider Assembly), Washer-Spring | 2 |
| 04***12 | Ring,Snap | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : Work Equipment Control System : Hydraulic Piping (2/2) (Front Attachment Line)
| 01***20 | Bolt,(For Quick Shift) (Mitsubishi) | 2 |
| 01***30 | Bolt,(For Quick Shift) (Mitsubishi) | 5 |
| 01***35 | Bolt,(For Quick Shift) (Mitsubishi) | 2 |
Komatsu : Wa20-1(S/N 1001-Up) : Work Equipment Control System : Hydraulic Piping (Dump Cylinder Line)
| 07***23 | O-Ring,(For 2nd Travel Speed) (Op) | 2 |
| 07***09 | Hose | 2 |
| 07***06 | Hose,(L=600) | 2 |
Komatsu : Wa20-1(S/N 1001-Up) : Work Equipment Control System : Hydraulic Piping (Lift Cylinder Line)
| 01***20 | Bolt,(For Quick Shift) (Mitsubishi) | 2 |
| 01***25 | Bolt,(For Canvas Canopy?Head Guard) | 2 |
| 01***35 | Bolt,(For Quick Shift) (Mitsubishi) | 2 |
Komatsu : Wa20-1(S/N 1001-Up) : Work Equipment Control System : Hydraulic Piping (Pressure Pick-Up Line) (For Back Hoe)
| 01***20 | Bolt,(For Quick Shift) (Mitsubishi) | 3 |
| 01***40 | Bolt, Mount Master Brake Cylinder | 1 |
| 01***11 | Nut,(With Under Mirror) | 6 |
Komatsu : Wa20-1(S/N 1001-Up) : Work Equipment Control System : Hydraulic Piping (Suction And Delivery Line)
| 01***25 | Bolt,Without Revolution Sensor | 3 |
| 01***30 | Bolt,(For Mechanical Governor) | 4 |
| 01***20 | Bolt,(For Quick Shift) (Mitsubishi) | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : Work Equipment Control System : Hydraulic Pump
| 04***15 | Ring, Snap | 1 |
| 70***10 | Seal, Oil | 1 |
| 70***70 | Plate | 1 |
Komatsu : Wa20-1(S/N 1001-Up) : Work Equipment Control System : Hydraulic Tank
| 01***20 | Bolt,(For Quick Shift) (Mitsubishi) | 3 |
| 01***30 | Bolt,(Not Used With Emergency Str.) | 4 |
| 01***32 | Washer,(With Auto Emergency Steering) | 3 |
Komatsu : Wa20-1(S/N 1001-Up) : Work Equipment Control System : Lift Cylinder
| 01***20 | Bolt,(For Quick Shift) (Mitsubishi) | 1 |
| 01***08 | Nut,(For Russian) | 2 |
| 01***30 | Washer, Spring (Supplied W/Spider Assembly), Washer-Spring | 1 |
WA20-1(S/N 1001-UP) serial number reference
On this compact loader the ID plate is a riveted metal tag on the main frame, typically near the articulation joint or on the frame rail below the operator's seat/cab support; check both frame halves if it is not visible on one side. This is a pre-VIN-era Komatsu machine, so the plate reads simply as model WA20-1 followed by a plain numeric serial number (starting at 1001) - there is no embedded three-letter plant/region code to decode as on later Komatsu PIN formats.
| Prefix | Identifies | Notes |
|---|---|---|
| 1001-UP | Base WA20-1 production range | Standard factory designation for this compact wheel loader is model WA20-1 with serial number 1001 and up; no separate three-letter alpha PIN prefix is used, just the model code plus a plain numeric serial. Built roughly 1987-1989. Fitted with the 4D94 (4D94-2) diesel engine, shared with the WA30-1 loader of the same era. |
| 1773-UP | Later documentation printing point (unconfirmed as a distinct build variant) | Some operation and maintenance manual coverage for this model begins at S/N 1773 and up rather than 1001. This looks like a mid-run manual reprint or later print date rather than a documented parts or configuration change. Confirm with dealer before treating it as a separate build variant. |
Frequently asked questions
What engine does the Komatsu WA20-1 (S/N 1001-UP) use?
It runs a Komatsu 4D94-2 diesel: naturally aspirated, mechanically governed, 4-cylinder, 2.94 L displacement, rated 36.5 kW (49 hp) gross. The same engine also powers the same-era WA30-1 loader. There is no ECM or electronic fuel control on this engine.
What is the operating weight of the Komatsu WA20-1 (S/N 1001-UP)?
Operating weight is about 3,978 kg (8,770 lb), placing it in the compact/utility wheel loader class with a roughly 0.6 m3 (0.79 cu yd) general-purpose bucket.
What replaced the Komatsu WA20-1 (S/N 1001-UP)?
Komatsu's WA20-2 (S/N 10001-UP) followed it in the WA20 line. The -2 series moved to a Yanmar-sourced 3-cylinder diesel in place of the Komatsu 4D94-2, a real powertrain change and not just a minor running update.
What WA20-1(S/N 1001-UP) owners discuss
What do operators and mechanics say about how the TORQFLOW transmission behaves in daily use?
Powershift TORQFLOW units on Komatsu wheel loaders of this era respond well when the transmission fluid stays clean and at the correct level. Hesitation on shift, slipping under load, or delayed engagement almost always trace back to contaminated or low fluid, a plugged sump screen, or worn clutch packs rather than a control problem — this machine predates electronic transmission controls, so there is no solenoid or module to chase. Check fluid condition and the sump screen first on any shift complaint. Regular fluid and filter changes matter more on a machine this age than on newer equipment, since seals and clutch material have had decades to degrade.
Where does wear show up first on a compact loader like this, and what needs the most attention?
Most wear on a small articulated loader concentrates at the center articulation pin, the steering cylinder pivots, and the loader linkage pins rather than in a track undercarriage — this machine rides on tires, so there's no track chain or roller wear to track. Daily greasing of every pivot point is the single biggest factor in pin and bushing life; skipping it, or greasing over a dirty fitting that pushes grit into the bushing, is the most commonly cited cause of premature play. Excess play at the articulation joint affects steering response and should be checked and corrected rather than dismissed as normal wear — have your dealer verify articulation and steering-cylinder pin tolerances if you feel looseness in the steering.
What quirks come up with the naturally aspirated engine, especially in cold weather?
The engine in this loader is a mechanically governed, naturally aspirated diesel with no electronic controls, so cold starting depends entirely on glow plugs (or an intake air heater) and injector condition. Extended cranking, rough idle, or white smoke on startup in cold weather point to weak glow plugs, a bad glow plug relay/timer, or aging injectors rather than any sensor fault. Because there's no engine control module to compensate for wear, performance drifts gradually with injector and compression condition over the years rather than throwing a code — owners generally judge engine health by start behavior, smoke color, and oil consumption instead of a diagnostic readout.
What electrical problems are most common on equipment this old with no computer controls?
With no engine control module or sensor network, electrical complaints on machines of this vintage are almost always basic charging-and-starting issues: a weak or sulfated battery, corroded ground and terminal connections, worn alternator brushes or a failing voltage regulator, or a sticking starter solenoid. Gauges and warning lights are simple analog circuits — a gauge reading wrong or a light staying on is more often a bad ground or loose connector than a failed sender. Check connections and charging voltage at the battery before replacing any component.
Are hydraulic leaks or sluggish bucket/loader response common complaints, and what usually causes them?
A hydraulic pump that starts whining is the classic sign of low fluid or air getting into the suction side — check fluid level and hose connections first. Sluggish bucket or lift-arm response on an older machine like this is usually fluid contamination or age-related wear in pump and valve internals, not a single failed part. Weeping at cylinder rod seals is common as chrome and seals age; wipe the rods down periodically to catch it early. Any loss of hydraulic pressure that affects steering response is a safety item — have your dealer verify steering-circuit pressure and cylinder condition rather than continuing to operate with a suspect steering system.
What should a buyer specifically check before purchasing a used WA20-1(S/N 1001-UP)?
Buyers are generally advised to check the bucket cutting edge and teeth for wear, inspect cylinder chrome for pitting or leaks by wiping the rods, and work every pivot pin for play — the articulation joint and loader linkage first. Confirm all four tires match in size and brand and wear evenly, since mismatched or unevenly worn tires point to alignment or loading issues. Run the machine through a full cold start to check glow-plug/cold-start behavior, and check TORQFLOW fluid for color and smell rather than just level. Because this is a small, long-discontinued model, sourcing exact-fit engine and hydraulic parts can take longer than for a current model — factor that into ownership cost before buying. Confirm the serial number falls in the correct production range for whatever spec sheet or manual you're relying on, since Komatsu revised these small loaders across more than one serial break.
Is this loader generally seen as reliable to keep running today, given its age?
The consensus on simple, pre-electronic machines like this is that they're mechanically straightforward and easy for an independent mechanic to work on, with no modules or sensors to chase. The tradeoff is age: hoses, seals, wiring insulation, and rubber components have had decades to harden or degrade even on a low-hour example, so a mechanically simple machine can still need a round of hoses, seals, and wiring cleanup after long storage or intermittent use. Owners of this class of loader generally say routine greasing, fluid changes, and prompt attention to small leaks keep them running for a very long service life.
Compiled from owner and technician discussions across the industry — experiences vary by serial range and machine history.
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