Komatsuwheel loadersmall ( - wa120 / sk*)
Komatsu SK09J-1(S/N SK09JF20001-Up)
Maintenance schedule, common problems & OEM parts breakdown
The SK09J-1(S/N SK09JF20001-Up) is a compact wheeled loader in Komatsu's small-frame lineup, grouped by Komatsu alongside its WA120 in the same size class. It steers by varying wheel speed side to side instead of through a center-hinge articulation joint. Komatsu built this first SK09J series from roughly 1997 to 1999 under the SK09JF20001-Up serial range. Power comes from a four-cylinder Perkins 1004-4 diesel rated around 51 kW (68 hp) gross, driving a machine with an operating weight near 3.4 t (7,496 lb) and a rated operating capacity of about 870 kg (1,918 lb). Komatsu offered it as a straight front loader or with a factory rear backhoe/excavator arm and stabilizer legs, turning the same chassis into a loader-backhoe combination unit. The line traces back to FAI, an Italian compact-equipment builder Komatsu partly acquired in 1991 and fully absorbed by 1995; the SK09J-1 launched as Komatsu dropped the FAI badge in 1997. The SK09J-2 replaced it in 1999.
The main change at the SK09J-2 update was the engine: Komatsu moved from the Perkins 1004-4 to one of its own four-cylinder diesels, rated close to 50 kW (67 hp) net, while carrying over the same operating weight, bucket size, tire fitment, and roughly 13 km/h (8 mph) travel speed. Because the two generations share a near-identical loader/backhoe platform, wear parts such as tires, cylinder seals, arm bushings, and chassis grease fittings interchange across the -1 and -2 range even though engine parts do not. These small European-market loaders never sold in the volumes of Komatsu's mainline WA-series wheel loaders, so surviving SK09J-1 units are less common today and mostly circulate through European dealers and parts networks. Their draw for current owners is a simple, mechanically governed pre-electronic driveline with no ECM or onboard diagnostics, making it a straightforward machine to keep running with basic mechanical skills and correctly identified parts.
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 SK09J-1(S/N SK09JF20001-Up) specifications
Engine
| Engine model | Perkins 1004-4, four-cylinder liquid-cooled diesel. The later SK09J-2 generation carried a different four-cylinder diesel producing roughly 50 kW (67 hp) net; this Perkins unit is specific to the SK09J-1 range. |
| Gross power | 51 kW (68 hp) |
| Cylinders | 4 |
| Displacement | Approximately 3.9 L (243 cu in), Perkins 1004 four-cylinder family |
| Emissions tier | Not published for this generation |
Weights
| Operating weight | 3.4 t (7,496 lb) |
| Rated operating capacity | 870 kg (1,918 lb) |
| Ground pressure | Not published for this model |
Dimensions
| Bucket capacity | Approximately 0.45 m³ (0.59 cu yd) with standard toothed shovel. A smaller figure near 0.08 m³ (0.10 cu yd) is also cited for a different bucket option - varies by configuration |
| Standard tires | 12-16.5 |
| Transport length | Approximately 3.2-3.4 m (10.5-11.1 ft), varies by measurement point |
| Transport width (over tires) | Approximately 1.74 m (5.7 ft) |
| Transport height | Approximately 2.1-2.3 m (7.0-7.4 ft), varies by measurement point |
| Wheelbase | Approximately 1.0 m (3.3 ft) - platform figure, not separately confirmed for this exact serial range |
| Ground clearance | Approximately 24 cm (9.5 in) - platform figure, not separately confirmed for this exact serial range |
Performance
| Max travel speed | 13 km/h (8.1 mph) |
| Operating speed | Approximately 8 km/h (5 mph) |
| Breakout force | Approximately 24 kN (5,401 lbf) - platform figure, not separately confirmed for this exact serial range |
| Turning radius (center, with bucket) | Approximately 2.05 m (80.8 in) - platform figure, not separately confirmed for this exact serial range |
Service capacities (summary)
| Fuel tank | Approximately 80 L (21.2 gal) - platform figure, not separately confirmed for this exact serial range |
| Hydraulic system | Approximately 50 L (13.3 gal) - platform figure, not separately confirmed for this exact serial range |
| Engine oil | Approximately 9 L (2.4 gal) - platform figure, not separately confirmed for this exact serial range |
| Cooling system | Not documented for this model - verify with your dealer |
Values vary by configuration, region, and serial range — confirm against your machine before planning transport or lifts.
SK09J-1(S/N SK09JF20001-Up) fluids & capacities
| System | Capacity | Recommended fluid |
|---|---|---|
| Engine crankcase (with filter) | Approx. 9.1 L (2.4 US gal) reported for this compact wheel loader platform. Not documented independently for this exact serial range - verify with your dealer or the OMM before service. | Komatsu Genuine engine oil (EO series), SAE 15W-40, API CI-4 / JASO DH-1, for ambient temperatures around 0°C to 45°C. Drop to 10W-30 or 10W below -15°C per Komatsu's seasonal viscosity guidance. |
| Cooling system | Not documented for this exact serial range - verify with your dealer or the OMM before service. | Komatsu Supercoolant AF-NAC, ethylene-glycol based, supplied pre-mixed for year-round use. Do not mix with other coolant types. |
| Fuel tank | Approx. 80 L (21.2 US gal) reported for this compact wheel loader platform. Not documented independently for this exact serial range - verify with your dealer or the OMM before service. | No. 2-D diesel fuel (ASTM D975) or EN590 equivalent. Switch to a winter-grade, low-cloud-point diesel in cold climates. |
| Hydraulic system (tank and circuit) | Approx. 50.3 L (13.3 US gal) total system reported for this compact wheel loader platform. Not documented independently for this exact serial range - verify with your dealer or the OMM before service. | Komatsu Genuine hydraulic oil (HO series), ISO VG46, DIN 51524 Part 2 HLP, for normal ambient use. Use ISO VG32 in cold climates and ISO VG68 in consistently hot climates. |
| Transmission / axle differentials (front and rear) | No published capacity found for this model. Verify with your dealer or the OMM before service. | Komatsu Genuine powertrain oil (TO series) or axle oil (AXO series), or an equivalent SAE 80W-90 GL-4/GL-5 gear oil, depending on the specific component fitted. |
| Grease points (all fittings) | Applied per lubrication-point schedule. No reservoir capacity applies. | Komatsu Genuine grease G2-LI, lithium EP2 multipurpose grease, for all chassis, loader-arm, and attachment grease points. |
Capacities are refill values from factory literature — always fill to the dipstick/sight gauge, not the number.
Komatsu SK09J-1(S/N SK09JF20001-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 SK09J-1(S/N SK09JF20001-Up) beyond the schedule
Predictive Maintenance & Fluid Analysis
Run oil analysis on the Perkins 1004-4 crankcase at every oil change and watch for coolant contamination; the oil cooler core is the more likely leak point ahead of the head gasket if the dipstick turns milky. Track hydraulic oil condition on the loader and backhoe circuits, since seal wear shows up first as slow cylinder creep with the controls centered. Sample front and rear differential and final-drive oil at scheduled changes to catch bearing wear before a hub failure interrupts an already-thin European parts supply.
Corrective & Common Repairs
Hard cold starts and lingering white smoke usually trace to a weak thermostart element rather than the injection pump; check its relay and wiring first. High-hour units commonly develop a fuel weep at the injection pump's throttle-shaft seal and injectors that seize in the bore from corrosion, not fuel quality. Loader or backhoe arm creep with controls centered points to worn cylinder seals or a relief valve holding open. Clean corroded connectors at the seat interlock switch and chassis grounds before chasing intermittent no-crank complaints.
Overhaul & Rebuild Points
Plan a full driveline evaluation once oil analysis or a compression test flags the Perkins 1004-4 for bearing or liner wear; rebuild the injection pump alongside it since output drifts on the same timeline. Loader and backhoe cylinders on high-hour machines need reseal or replacement once creep can't be tuned out at the relief valve. Front and rear differential/final-drive units wear from the constant scrub loads of differential-steer operation and are worth a teardown inspection at major overhaul rather than a seal-only fix.
Seasonal & Environment Servicing
Switch to a lower-viscosity engine oil grade and winter-grade diesel before cold weather, and confirm the thermostart element is working since it is this engine's only cold-start aid. Keep the Komatsu-spec ethylene-glycol coolant at full strength year-round rather than diluting it. In hot or dusty yard duty, step up air-cleaner element checks and hydraulic oil viscosity grade, and rinse road salt or de-icer off axle and hub seals promptly in winter road use to protect the differential-steer hubs from corrosion.
SK09J-1(S/N SK09JF20001-Up) common service parts
| Part number | Part | Notes | |
|---|---|---|---|
| PK2656615 | Fuel Filter, Assembly | Fuel system service | Check fitment → |
| 848001074 | Air Filter, Assembly | Air intake service | Check fitment → |
| PK2654403 | Oil Filter | Lubrication service | Check fitment → |
| P3773K808 | Filter Head | Scheduled service item | Check fitment → |
| 338807062 | Filter Support | Scheduled service item | Check fitment → |
Always confirm against your machine's serial number — cross-check any part in Heavy Parts AI before ordering.
SK09J-1(S/N SK09JF20001-Up) fault codes & troubleshooting
| Code | Meaning | Likely cause | What to do |
|---|---|---|---|
| Oil pressure warning lamp (no alphanumeric code) | Engine oil pressure below the minimum switch setting | Low oil level, worn oil pump, clogged suction screen, or failed pressure switch | Stop engine immediately, check oil level, inspect for leaks before restart |
| Coolant temperature warning lamp (no alphanumeric code) | Engine coolant temperature above the safe operating threshold | Low coolant, blocked radiator fins, slipping or broken fan belt, faulty thermostat | Idle down, let engine cool, check coolant level and radiator before continuing work |
| Charge (alternator) warning lamp (no alphanumeric code) | Battery not receiving charge from the alternator | Broken or slipping belt, failed alternator, loose or corroded wiring connection | Check belt tension and battery terminals, test alternator output |
| Air cleaner restriction indicator (no alphanumeric code) | Intake air filter element restriction has reached the service limit | Clogged or saturated air filter element | Inspect and clean or replace the air filter element |
Codes and remedies are general guidance for this model family — always confirm with diagnostic tooling and your dealer before major repairs.
SK09J-1(S/N SK09JF20001-Up) attachments & work tools
Front loader bucket
Standard general-purpose front bucket sized for this compact wheeled loader class, in the roughly 0.45 m3 range. Mounts on the machine's front tool bar with a bolt-on cutting edge.
Front quick-attach tool bar
Frame tool bar / shovel connection lets the front bucket and other loader-type tools go on and off without pinning, typical of this compact wheeled loader platform.
Rear backhoe/excavator arm
Factory-documented rear-mounted swing arm with its own boom, dipper arm, and bucket cylinders, plus a dedicated excavator control valve and PPC joystick. Converts the base loader into a combination loader-backhoe.
Backhoe digging buckets
Narrow trenching buckets for the rear arm, offered in roughly 300-600 mm (about 12-24 in) widths to match different trench and utility-digging jobs. Width mounts to the same arm/bucket cylinder linkage.
Rear stabilizer legs / outriggers
Hydraulic stabilizer feet at the rear brace the machine while the backhoe arm digs and retract for travel. Fitted as part of the backhoe-arm configuration, not on the plain loader setup.
Hydraulic hammer/breaker provision
Dedicated auxiliary lines and quick couplers allow a hydraulic breaker to be mounted either on the front tool plate or on the backhoe arm. A separate circuit is documented for a hand-held hammer.
Auxiliary hydraulic (3rd function) kit
Pedal-controlled auxiliary circuit with quick-disconnect couplings powers front attachments beyond basic bucket curl and lift, wired into the machine's PPC pilot-hydraulic system.
Road-travel / homologation package
Optional road-legal kit documented for this model: turn-signal switch, work lighting, wheel chains, and ID plates for travel on public roads between job sites, consistent with small European utility-loader practice for this class.
All SK09J-1(S/N SK09JF20001-Up) assemblies by section
Every catalogued assembly group for the Komatsu SK09J-1(S/N SK09JF20001-Up). Open an assembly to preview the parts inside — full OEM part numbers are available in Heavy Parts AI.
Control System
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Control System : Auxiliary Hydraulic Kit Control Pedal
| 20***00 | Pedal | 2 |
| 33***58 | Pedal | 1 |
| 33***64 | Handle | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Control System : Fuel Control Lever
| 20***00 | Pedal | 1 |
| 33***78 | Support | 1 |
| 33***64 | Plate | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Control System : Hydraulic Piping (Bucket Lifting And Tipping Ppc Line)
| 33***53 | Link (For Homologation Road) | 1 |
| 39***64 | Hose | 1 |
| 39***89 | Hose | 2 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Control System : Hydraulic Piping (Travel Ppc Line)
| 33***07 | Support | 1 |
| 33***09 | Tee | 2 |
| 39***42 | Hose | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Control System : Safety Bars
| 33***28 | Bushing | 2 |
| 33***66 | Plate R.H | 1 |
| 33***67 | Plate L.H | 1 |
Engine
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Engine : Air Intake - Exhaust Manifold
| P3***31 | Manifold, Exhaust | 1 |
| PK***08 | Intake Heater | 1 |
| P3***03 | Gasket | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Engine : Alternator
| P2***52 | Regulator | 1 |
| P2***60 | Kit, Washer | 1 |
| P2***61 | Kit, Terminal | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Engine : Alternator And Mountings
| 33***32 | Adjusting Support | 1 |
| 33***55 | Adjusting Support | 1 |
| P3***21 | Bracket | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Engine : Application Miscellaneous And Auxiliaries
| PK***54 | Plug | 1 |
| P3***46 | Pipe | 3 |
| P2***54 | Plug | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Engine : Crankshaft - Pistons And Connecting Rods
| PK***81 | Kit, Crankshaft, Assembly | 1 |
| PK***12 | Key | 1 |
| PK***2B | Kit, Bearing (--0.50 mm) | 0 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Engine : Cylinder Block
| PK***10 | Plug | 6 |
| P3***44 | Gasket | 1 |
| PK***69 | Spacer | 4 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Engine : Cylinder Head
| 87***29 | Motor, Assembly | 1 |
| PK***10 | Plug | 1 |
| P3***01 | Plate | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Engine : Feed Pump
| P2***67 | Pump, Assembly | 1 |
| P2***33 | Screw | 4 |
| P3***16 | Plate | 2 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Engine : Flywheel Housing, Flywheel And Starter Ring
| P3***54 | Cover | 1 |
| P4***95 | Flywheel, Assembly | 1 |
| PK***25 | Pin | 2 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Engine : Fuel Filter
| PK***15 | Fuel Filter, Assembly | 1 |
| P2***16 | Washer | 1 |
| P3***12 | Nut | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Engine : Fuel Injection Nozzle
| PK***89 | Shim, 0.700 mm | 0 |
| PK***87 | Shim, 0.660 mm | 0 |
| PK***83 | Shim, 0.580 mm | 0 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Engine : Fuel Injection Piping
| P2***19 | Hose-Clamp | 2 |
| P3***02 | Hose-Clamp | 4 |
| P3***12 | Nut | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Engine : Fuel Injection Pump
| P2***16 | Plate | 1 |
| P2***66 | Rotor | 1 |
| P2***30 | Shaft | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Engine : Gasket Set (Lower)
| P3***03 | Gasket | 1 |
| P3***07 | Gasket | 1 |
| PU***51 | Kit, Gasket | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Engine : Gasket Set (Upper)
| P3***44 | Gasket | 1 |
| P3***09 | Gasket | 1 |
| P3***03 | Gasket | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Engine : Gear Drive Auxiliary Drive
| P2***49 | Screw | 1 |
| P2***02 | Screw | 1 |
| P2***04 | Screw | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Engine : Kit Gasket Injection Pump
| PU***44 | Kit, Gasket | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Engine : Low Pressure Fuel System
| P4***03 | Pipe, Fuel | 1 |
| P3***12 | Nut | 2 |
| P3***06 | Pipe, Fuel | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Engine : Lubricating Oil Filter And Breather
| P3***25 | Pipe | 1 |
| P2***10 | Screw | 1 |
| P2***95 | Hose-Clamp | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Engine : Lubricating Oil Pump And Delivery Housing
| P3***03 | Spring | 1 |
| P3***25 | Washer | 1 |
| P3***11 | Flange | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Engine : Lubricating Oil Sump
| 33***04 | Union (Only For Germany) | 1 |
| 33***72 | Pipe | 1 |
| 33***39 | Support | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Engine : Oil Filter
| PK***08 | Sleeve | 1 |
| P4***56 | Pipe, Oil | 1 |
| P3***05 | Hose-Clamp | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Engine : Pre-Fuel Filter
| P2***16 | Washer | 1 |
| PK***04 | Sleeve | 3 |
| P2***75 | Tank | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Engine : Pulley, Crank
| P2***11 | Screw | 4 |
| P3***41 | Pulley, Crank Shaft | 1 |
| P3***37 | Screw | 3 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Engine : Rocker Shaft
| P2***31 | Stud | 3 |
| PK***22 | Screw | 1 |
| PK***79 | Screw | 8 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Engine : Starter Motor
| P2***09 | Kit, Repair | 1 |
| P2***04 | Nut | 3 |
| P2***71 | Starter Motor, Assembly | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Engine : Throttle And Stop Controls
| P3***04 | Bracket | 1 |
| PK***02 | Washer, Spring | 1 |
| P2***01 | Screw | 2 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Engine : Timing Gear And Camshaft
| PK***12 | Key | 1 |
| P4***23 | Idle Gear, Assembly | 1 |
| P2***03 | Nut | 2 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Engine : Water Pump - Thermostat
| 88***15 | Water Temperature Transmitter (Instrument) | 1 |
| P2***55 | Seal, Oil | 1 |
| P2***05 | Seal, Oil | 1 |
Engine Related Parts And Electrical System
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Engine Related Parts And Electrical System : Air Filter - Exhaust Silencer
| 33***54 | Muffler Support | 1 |
| 33***56 | Pipe, Upper | 1 |
| 33***62 | Filter Support | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Engine Related Parts And Electrical System : Dashboard (1/2)
| 33***03 | Dashboard | 1 |
| 81***11 | Position, Plate | 1 |
| 88***55 | Wrench | 2 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Engine Related Parts And Electrical System : Dashboard (2/2)
| 80***60 | Screw | 4 |
| 81***87 | Washer (Optional) | 4 |
| 85***69 | Gasket (Optional) | 0 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Engine Related Parts And Electrical System : Electric System (Omologation Road And Work Light)
| 33***00 | Support | 1 |
| 33***03 | Support (Version A) | 1 |
| 33***51 | Support, R.H | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Engine Related Parts And Electrical System : Electrical System (2/3)
| 30***95 | Support | 1 |
| 33***04 | Support | 1 |
| 33***05 | Protection | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Engine Related Parts And Electrical System : Electrical System (3/3)
| 30***14 | Retainer | 1 |
| 33***51 | Support | 1 |
| 50***07 | Rubber | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Engine Related Parts And Electrical System : Engine Mounting Parts
| 33***68 | Support, Front, R.H | 1 |
| 33***69 | Support, Front, L.H | 1 |
| 33***22 | Support, Rear, L.H | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Engine Related Parts And Electrical System : Fuel Piping
| 20***57 | Plug, Assembly | 1 |
| 30***77 | Pipe | 2 |
| 30***78 | Pipe | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Engine Related Parts And Electrical System : Power Take Off
| 33***16 | Washer | 2 |
| 33***53 | Support | 1 |
| 33***65 | Cover Flange | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Engine Related Parts And Electrical System : Radiator (1/2)
| 30***38 | Hose | 1 |
| 30***66 | Hose | 1 |
| 33***57 | Protection | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Engine Related Parts And Electrical System : Radiator (2/2)
| 80***29 | Damper | 4 |
| 87***11 | Plug | 1 |
| 87***25 | Hydraulic Motor | 1 |
Frame
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Frame : Brake Group
| 33***81 | Cock, Assembly | 1 |
| 33***85 | Union | 1 |
| 33***00 | Block | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Frame : Frame
| 20***20 | Plug | 2 |
| 20***80 | Ballast | 2 |
| 33***68 | Shim | 2 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Frame : Transmission
| 20***90 | Crown Wheel | 2 |
| 33***07 | Washer | 2 |
| 33***09 | Link | 2 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Frame : Wheels
| 33***11 | Column | 12 |
| 33***52 | Rim | 4 |
| 33***53 | Rim (Opzionale) | 4 |
Guard And Operator'S Cab
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Guard And Operator'S Cab : Cabin (1/2)
| 33***10 | Gasket, R.H | 1 |
| 33***11 | Gasket, L.H | 1 |
| 33***61 | Protection | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Guard And Operator'S Cab : Cabin (2/2)
| 33***27 | Spacer (For Mounting Safety Valves) | 1 |
| 33***78 | Retainer | 1 |
| 33***79 | Retainer | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Guard And Operator'S Cab : Engine Hood
| 33***52 | Support | 1 |
| 33***53 | Striker | 1 |
| 33***02 | Spring | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Guard And Operator'S Cab : Front Door
| 33***53 | Wiper, Assembly | 1 |
| 33***54 | Door, Assembly | 1 |
| 33***55 | Bracket | 2 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Guard And Operator'S Cab : Inner Cabin Cover
| 33***45 | Sheet | 1 |
| 33***02 | Cover | 1 |
| 33***16 | Sheet | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Guard And Operator'S Cab : Operator'S Cab (Equipment) (Only For Germany)
| 80***04 | Nut | 6 |
| 80***08 | Washer (Optional) | 4 |
| 80***09 | Washer | 2 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Guard And Operator'S Cab : Operator'S Seat
| 33***63 | Seat Belt, Assembly | 1 |
| 33***68 | Washer | 4 |
| 33***22 | Plate (Except Germany) | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Guard And Operator'S Cab : Rear Hood
| 33***54 | Hinge | 2 |
| 33***13 | Pin | 2 |
| 33***57 | Hood, Rear | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Guard And Operator'S Cab : Supports And Manipulators Ppc Valves
| 33***70 | Guide, R.H | 1 |
| 33***71 | Guide, L.H | 1 |
| 33***74 | Support, L.H | 1 |
Mark Plate
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Mark Plate : Equipment (For Road Circulation)
| 20***24 | Chain (With Stabilizers Only) | 2 |
| 33***23 | Plate, L.H | 1 |
| 33***24 | Plate, R.H | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Mark Plate : Equipment (Germany Version)
| 80***87 | Bolt | 4 |
| 80***08 | Nut (With Stabilizers Only) | 4 |
| 80***01 | Spring Washer (With Stabilizers Only) | 4 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Mark Plate : Mark Plate
| 30***38 | Plate ?Fai Komatsu? | 2 |
| 31***06 | Plate, Fki | 1 |
| 33***19 | Transfer Print Translation | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Mark Plate : Tools
| 33***35 | Support | 1 |
| 33***53 | V-Belt | 1 |
| 33***54 | Tools Bag | 1 |
Work Equipment
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Work Equipment : Arm
| 33***53 | V-Belt | 1 |
| 33***50 | Arm | 1 |
| 33***51 | Safety Bar | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Work Equipment : Arm (Excavator)
| 20***82 | Bucket, L=300 mm | 1 |
| 20***83 | Bucket, L=400 mm | 1 |
| 20***84 | Bucket, L=500 mm | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Work Equipment : Arm Cylinder (Excavator)
| 80***24 | Nut | 1 |
| 85***76 | Kit, Gasket | 1 |
| 86***07 | Fitting (Except Germany) | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Work Equipment : Boom Cylinder (Excavator)
| 80***24 | Nut | 1 |
| 85***77 | Kit, Gasket | 1 |
| 86***07 | Fitting (Except Germany) | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Work Equipment : Bucket
| 20***42 | Handle | 1 |
| 33***06 | Spacer | 6 |
| 33***18 | Link | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Work Equipment : Bucket Cylinder (Excavator)
| 50***01 | Bushing | 1 |
| 80***67 | Bolt (Optional) | 2 |
| 80***24 | Nut | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Work Equipment : Bucket Tipping Cylinder
| 39***49 | Bushing | 1 |
| 39***52 | Bushing | 1 |
| 39***13 | Dump Cylinder, L.H | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Work Equipment : Lifting Cylinder
| 39***52 | Bushing | 1 |
| 39***08 | Lift Cylinder, R.H | 1 |
| 39***09 | Lift Cylinder, L.H | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Work Equipment : Main Valve Support (Excavator)
| 80***46 | Bolt | 8 |
| 80***48 | Bolt | 1 |
| 80***97 | Screw | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Work Equipment : Outrigger Cylinder
| 80***18 | Nut | 1 |
| 86***07 | Fitting (Except Germany) | 2 |
| UE***41 | Cylinder Head | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Work Equipment : Rotation Group (Excavator)
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Work Equipment : Shovel Connection
| 33***50 | Support, R.H | 1 |
| 33***51 | Support, L.H | 1 |
| 33***52 | Pin | 2 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Work Equipment : Stabilizer Foot
| 33***51 | L.H. Stabilizator Foot | 1 |
| 33***52 | R.H. Stabilizator Foot | 1 |
| 33***55 | L.H. Cylinder, Assembly | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Work Equipment : Stabilizers And Frame (Excavator)
| 50***62 | Washer | 2 |
| 50***07 | Piston | 4 |
| 80***65 | Bolt | 4 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Work Equipment : Swing Bracket And 1st Arm (Excavator)
| 80***82 | Bolt | 2 |
| 80***73 | Screw | 2 |
| 80***92 | Dowel | 1 |
Work Equipment Control System
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Work Equipment Control System : Bucket Lifting Hydraulic System (Floating Version)
| 33***02 | Block | 1 |
| 39***98 | Hose | 1 |
| 39***72 | Hose | 2 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Work Equipment Control System : Equipment Unloading Kit
| 20***50 | Body (For Hammer On Plate And On Excavator) | 1 |
| 20***64 | Plug (For Hammer On Plate And On Excavator) | 1 |
| 20***05 | Clamp (For Hammer On Plate And Excavator) | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Work Equipment Control System : Excavator Control Valve (1/3)
| 80***92 | Screw | 4 |
| 80***98 | Screw | 4 |
| 80***09 | Nut (Version B) | 8 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Work Equipment Control System : Excavator Control Valve (2/3)
| 80***94 | Screw | 8 |
| 80***98 | Screw | 8 |
| 84***17 | Cap | 2 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Work Equipment Control System : Excavator Control Valve (3/3)
| 80***94 | Screw | 8 |
| 80***98 | Screw | 8 |
| 84***07 | Plug | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Work Equipment Control System : Final Drive (1/2)
| 80***49 | Screw | 2 |
| 84***98 | Hydraulic Motor | 1 |
| 84***73 | Spring | 11 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Work Equipment Control System : Final Drive (2/2)
| 80***74 | Screw | 2 |
| 84***09 | Plug | 2 |
| 84***40 | Cap Valve | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Work Equipment Control System : Hammer Hydraulic System (1st Part)
| 20***49 | Fitting (For Hammer On Plate And On Excavator) | 1 |
| 20***50 | Body (For Hammer On Plate And On Excavator) | 1 |
| 20***52 | Fitting (For Hand Hammer) | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Work Equipment Control System : Hammer Hydraulic System (2nd Part)
| 39***48 | Hose | 1 |
| 39***49 | Hose | 1 |
| 50***20 | Union | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Work Equipment Control System : Hydraulic Piping (Arm Cylinder Line) (Excavator)
| 50***43 | Union (For Homologation Road) | 2 |
| 80***08 | Nut (With Stabilizers Only) | 2 |
| 85***17 | O-Ring (For Homologation Road) | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Work Equipment Control System : Hydraulic Piping (Auxiliary Kit Line)
| 20***48 | Coupling, Assembly. (For Hammer On Plate And On Excavator) | 1 |
| 20***49 | Fitting (For Hammer On Plate And On Excavator) | 1 |
| 20***50 | Body (For Hammer On Plate And On Excavator) | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Work Equipment Control System : Hydraulic Piping (Boom Cylinder Line) (Excavator)
| 50***43 | Union (For Homologation Road) | 2 |
| 85***17 | O-Ring (For Homologation Road) | 1 |
| UE***30 | Hose | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Work Equipment Control System : Hydraulic Piping (Boom Swing Line) (Excavator)
| 50***43 | Union (For Homologation Road) | 2 |
| 80***82 | Bolt | 12 |
| 80***08 | Nut (With Stabilizers Only) | 12 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Work Equipment Control System : Hydraulic Piping (Bucket Cylinder Line) (Excavator)
| 50***12 | Union | 2 |
| 80***08 | Nut (With Stabilizers Only) | 1 |
| 85***17 | O-Ring (For Homologation Road) | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Work Equipment Control System : Hydraulic Piping (Bucket Lifting Cylinder)
| 20***70 | Clamp | 4 |
| 30***22 | Clamp | 2 |
| 33***55 | Pipe | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Work Equipment Control System : Hydraulic Piping (Bucket Tipping Cylinder)
| 20***70 | Clamp | 2 |
| 33***15 | Retainer | 1 |
| 33***51 | Pipe | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Work Equipment Control System : Hydraulic Piping (Delivery And Return Line) (Excavator)
| 20***48 | Coupling, Assembly. (For Hammer On Plate And On Excavator) | 1 |
| 20***49 | Fitting (For Hammer On Plate And On Excavator) | 1 |
| 20***50 | Body (For Hammer On Plate And On Excavator) | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Work Equipment Control System : Hydraulic Piping (Locking Cylinder Line) (Excavator)
| 50***44 | Union | 5 |
| 50***02 | Union Tee | 1 |
| 50***08 | Elbow (For Hydraulic Lock) | 2 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Work Equipment Control System : Hydraulic Piping (Oil Cooler And Return Line) : Unit_02_of_02
| 20***30 | Plug | 1 |
| 20***06 | Union | 1 |
| 31***95 | Union | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Work Equipment Control System : Hydraulic Piping (Oil Cooler And Return Line) : Unit_01_of_02
| 20***30 | Plug | 1 |
| 31***95 | Union | 1 |
| 33***75 | Union | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Work Equipment Control System : Hydraulic Piping (Outrigger Line Stabilizers) (Excavator)
| 50***12 | Union | 4 |
| 85***17 | O-Ring (For Homologation Road) | 1 |
| UE***42 | Hose | 4 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Work Equipment Control System : Hydraulic Piping (Outrigger Line) (1/2)
| 33***12 | Union | 1 |
| 39***57 | Hose | 2 |
| 39***65 | Hose | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Work Equipment Control System : Hydraulic Piping (Outrigger Line) (2/2)
| 33***50 | Pipe | 4 |
| 33***01 | Clamp | 1 |
| 39***20 | Hose | 2 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Work Equipment Control System : Hydraulic Piping (Suction Delivery Line) : Unit_02_of_02
| 20***90 | Pressure Take-Up | 1 |
| 33***79 | Union | 1 |
| 33***03 | Elbow | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Work Equipment Control System : Hydraulic Piping (Suction Delivery Line) : Unit_01_of_02
| 20***90 | Pressure Take-Up | 1 |
| 33***07 | Support | 1 |
| 33***79 | Union | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Work Equipment Control System : Hydraulic Piping (Travel Motor Line) (1/2)
| 33***81 | Pipe | 1 |
| 33***04 | Support | 1 |
| 39***30 | Hose | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Work Equipment Control System : Hydraulic Piping (Travel Motor Line) (2/2)
| 20***43 | Union | 1 |
| 33***10 | Union | 2 |
| 33***67 | Pipe | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Work Equipment Control System : Hydraulic Pump (1/2)
| 80***35 | Ring, Snap | 1 |
| 80***62 | Ring, Snap | 2 |
| 84***40 | O-Ring | 2 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Work Equipment Control System : Hydraulic Pump (2/2)
| 80***35 | Ring, Snap | 1 |
| 80***62 | Ring, Snap | 2 |
| 84***40 | O-Ring | 2 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Work Equipment Control System : Hydraulic Tank
| 20***90 | Plug | 1 |
| 20***40 | Indicator Oil Level | 1 |
| 33***51 | Hydraulic Tank | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Work Equipment Control System : Loader Control Valve (1/12)
| 80***77 | Screw | 4 |
| 84***69 | Tie-Rod, Assembly | 4 |
| 84***70 | Kit, Gasket (Control Valve, Assembly.) | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Work Equipment Control System : Loader Control Valve (2/2)
| 80***77 | Screw | 8 |
| 84***50 | Element, Assembly | 1 |
| 84***52 | Element, Assembly | 1 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Work Equipment Control System : Loader Control Valve (For Outrigger)
| 80***77 | Screw | 4 |
| 84***50 | Element, Assembly | 2 |
| 84***67 | Tie-Rod, Assembly | 4 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Work Equipment Control System : Main Valve Element For Hammer
| 80***92 | Screw | 4 |
| 80***98 | Screw | 4 |
| 80***09 | Nut (Version B) | 8 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Work Equipment Control System : Ppc Valve (Lifting And Overturning Bucket)
| 84***52 | Washer | 8 |
| 84***56 | Shim, 0.100 mm | 0 |
| 84***57 | Shim, 0.200 mm | 0 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Work Equipment Control System : Self-Levelling Valve
| 84***25 | Valve | 1 |
| 84***26 | O-Ring | 2 |
| 84***27 | Plug | 2 |
Komatsu : Sk09j-1(S/N Sk09jf20001-Up) : Work Equipment Control System : Translation Manipulator
SK09J-1(S/N SK09JF20001-Up) serial number reference
The PIN/serial plate on this class of Komatsu compact wheel loader sits on the main frame, typically near the operator seat area or on the chassis at the rear, under or near the support arm. The stamped number reads as the model-code stem (SK09JF) followed by a five-digit running number; the model stem itself works as the identifying prefix rather than a separate plant or region code, and the numeric tail shows where the unit falls in the production run, with 20001 marking the start of this range.
| Prefix | Identifies | Notes |
|---|---|---|
| SK09JF | SK09J-1 - original series (approx. 1997-1999 build) | Only serial block documented for this machine, starting at SK09JF20001-Up. Identifies the first-series compact wheel loader ahead of the later SK09J-2 update. This series runs the Perkins 1004-4 diesel engine, rated around 51 kW (68 hp) gross. The follow-on SK09J-2 update switched to a different engine, so parts and service specs tied to that later engine do not carry back to this range. No separate plant-code or regional sub-prefix is documented within this range. |
Frequently asked questions
What engine powers the Komatsu SK09J-1(S/N SK09JF20001-Up)?
A four-cylinder Perkins 1004-4 diesel rated around 51 kW (68 hp) gross. Komatsu switched to one of its own four-cylinder diesels, rated close to 50 kW (67 hp) net, on the following SK09J-2 generation.
What is the operating weight of the Komatsu SK09J-1(S/N SK09JF20001-Up)?
Approximately 3.4 t (7,496 lb), with a rated operating capacity near 870 kg (1,918 lb). Exact figures can vary slightly with the front bucket or rear backhoe-arm configuration fitted.
What replaced the Komatsu SK09J-1(S/N SK09JF20001-Up)?
The SK09J-2, built from about 1999 to 2003 on the same compact loader chassis, with a different four-cylinder diesel replacing the Perkins engine.
What SK09J-1(S/N SK09JF20001-Up) owners discuss
What do owners say about cold-start behavior and white smoke on this Perkins-powered loader?
This engine generation uses a fuel-fed thermostart (glow) element rather than a bank of conventional glow plugs. A weak or fouled thermostart element is the most commonly reported cause of hard cold starts and heavy white smoke at start-up. Light white smoke on a cold morning that clears once the engine reaches operating temperature is considered normal; smoke that lingers after warm-up more often points to worn valve guides letting oil drain into the cylinders overnight, or a thermostart circuit passing raw fuel into the intake. Check the thermostart element and its relay/wiring before condemning the injection pump.
Are there known fuel-system quirks with this engine on the SK09J-1?
The mechanical injection pump on this engine family is reported to develop a fuel weep at the throttle-shaft seal over time, usually showing up as a small diesel stain at the pump's top cover rather than a driveability complaint. A second recurring item on high-hour examples is an injector seizing in its bore, more often from corrosion around the nozzle than from fuel quality. Freeing a stuck injector calls for heat and penetrating oil worked in gradually, not force, to avoid damaging the cylinder head. Both issues are treated as routine wear on this engine, not a defect tied to one production run.
What undercarriage or tire wear pattern is typical for this loader?
This machine steers by running the left and right wheel pairs at different speeds instead of through an articulation joint, so every turn scrubs the tires across the ground rather than rolling them through the turn. Owners of this class of differential-steer loader report faster tread wear than an equivalent articulated wheel loader, especially on paved or abrasive yard surfaces, with the scrub load shifting between the front and rear tires depending on whether the bucket is loaded or empty. This is expected wear from the steering design, but uneven wear side-to-side is still worth checking against tire pressure and hub condition rather than assumed to be normal.
Do owners report hydraulic cylinder drift or creep on the loader or backhoe circuit?
Slow bucket or lift-arm creep with the controls centered is a commonly reported complaint on small loaders and backhoes of this vintage. Mechanics trace it to a short list of causes: worn cylinder seals allowing internal bypass, a control-valve spool not sealing fully to tank, or a load-holding/relief valve that has weakened or picked up debris and is cracking open early. Because drift on the loader arms or a rear backhoe arm can let a raised load or boom settle unexpectedly, have your dealer verify the relief valve settings and cylinder seal condition rather than just topping off the reservoir.
What electrical or sensor issues come up most on this generation of loader?
Reported electrical complaints on machines of this age center on corrosion rather than outright component failure: connectors at the seat/safety interlock switch, the thermostart relay, and chassis grounds are the usual suspects behind an intermittent no-crank or a machine that cranks but will not fuel. Cleaning and re-seating these connections resolves most no-start complaints before any switch needs replacing. Because the seat interlock is a safety device that keeps the loader from being driven or the arms operated with no one in the seat, have your dealer verify the switch and wiring rather than wiring around it.
Is coolant-in-oil or head gasket failure a known problem on this engine?
Coolant showing up in the engine oil, seen as a milky dipstick, is reported often enough on this engine family that mechanics check the oil cooler core for an internal leak before condemning the head gasket, since the cooler sits directly in the oil-to-coolant path and is the more common failure point. If the cooler checks out clean, a compression and leak-down test is the next step to confirm a head gasket or cracked cylinder head before any teardown.
What should a buyer check before purchasing a used SK09J-1 wheel loader?
Start the engine cold and confirm the smoke clears within a normal warm-up, then listen for injection pump or bearing noise once at operating temperature. Cycle the loader arms, and the backhoe if the machine has the factory rear attachment, through full travel under load and watch for cylinder creep with the controls centered. Check tires for even wear side-to-side, since a differential-steer machine pulling or dragging on one side will scrub one set of tires noticeably faster. Inspect hub and final-drive housings for leaks or play, and ask for maintenance records where available, since machines of this type are typically worked hard in yard or municipal service. If a rear backhoe is fitted, test its auxiliary hydraulic circuit and coupler under load rather than cycling it empty.
Compiled from owner and technician discussions across the industry — experiences vary by serial range and machine history.
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