Komatsuwheel loadersmall ( - wa120 / sk*)
Komatsu SK07-1(S/N 3440007-Up)
Maintenance schedule, common problems & OEM parts breakdown
The Komatsu SK07-1 (S/N 3440007-Up) is a compact wheel loader in Komatsu's small-utility class, built in the late 1990s at Komatsu's Este, Italy plant (the former FAI facility, later Komatsu Italia Manufacturing) rather than in Japan. A separate SK07-1 (S/N 1001-Up) population built in Japan with a different engine exists under the same bare model name; this write-up covers only the 3440007-Up Italy-built run. That run carries a Yanmar 4TN84 four-cylinder diesel rated at 29 kW (38.9 hp) and drives all four wheels through a hydrostatic transmission, with no geared final drives or separate axle oil sumps. Operating weight runs approximately 2,360 kg (5,203 lb), rated operating capacity approximately 634 kg (1,398 lb), and standard bucket capacity approximately 0.36 m³ (0.47 cu yd), placing it below Komatsu's WA65/WA70 compact wheel loader class. The smaller SK04 shared this mini-loader family with a lighter Perkins-powered build, and the SK07 nameplate later continued on separate serial blocks as the SK07J-1 and SK07J-2. Komatsu offered this chassis as a standard front-loader with a general-purpose bucket, with pallet forks, or converted to a tractor-loader-backhoe (TLB) configuration with an optional rear excavator attachment and its own stabilizer legs and hydraulic circuit.
Across the SK07 nameplate, the biggest split is build location and engine: this Italy-built 3440007-Up run uses the Yanmar 4TN84, the separate Japan-built 1001-Up run used a different engine, and the later SK07J-1/SK07J-2 variants moved to their own serial blocks. Configuration varied unit to unit more than the spec sheet did, with some machines leaving the factory as straight front-loaders and others as loader-backhoe combinations carrying a rear excavator kit and dedicated hydraulic circuit. In today's used and parts market this is a low-production, thinly documented machine: surviving units are scarce, service history is often incomplete, and parts support leans on Yanmar's shared industrial-engine network and Komatsu's compact-loader catalog rather than a dedicated aftermarket. Buyers value it as a tight-turning, mechanically simple loader for yard and small-site work where a full-size wheel loader is overkill, and the absence of electronics keeps it serviceable in the field with basic diesel-mechanic tools.
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 SK07-1(S/N 3440007-Up) specifications
Engine
| Engine model | Yanmar 4TN84, 4-cylinder direct-injection, liquid-cooled diesel |
| Rated power | 29 kW (38.9 HP) |
| Displacement | 1.91 L (116 cu in) |
| Cylinders | 4 |
| Emissions tier | Not documented for this serial range — machine predates modern emissions-tier regulation |
Weights
| Operating weight | 2,360 kg (5,203 lb) |
| Rated operating capacity | 634 kg (1,398 lb) |
Dimensions
| Standard tire size | 10-16.5 |
| Transport length/width/height, wheelbase, ground clearance | Not documented for this exact serial range in available spec sources — verify with your Komatsu dealer |
Performance
| Travel speed | 10 km/h (6.2 mph) |
| Bucket capacity | 0.36 m³ (0.47 cu yd) |
Service capacities (summary)
| Fuel tank, hydraulic system, engine oil, cooling system | Not documented for this exact serial range in available spec sources — verify with your Komatsu dealer or service manual |
Values vary by configuration, region, and serial range — confirm against your machine before planning transport or lifts.
SK07-1(S/N 3440007-Up) fluids & capacities
| System | Capacity | Recommended fluid |
|---|---|---|
| Engine crankcase (with filter) | approx. 5.3 L (5.6 US qt / 1.4 US gal) - Yanmar 4TN84 diesel | SAE 10W-30 or 15W-40 for normal/warm climates, SAE 5W-30 below freezing; API CD or CE service classification. Komatsu-brand equivalent: Komatsu EO. |
| Cooling system | not published for this exact serial range; this Yanmar water-cooled inline-4 family typically runs approx. 5.5-6.1 L (5.8-6.4 US qt) - varies by radiator/heater configuration, verify with your dealer | Ethylene-glycol based antifreeze/coolant, corrosion-inhibited, mixed with water to suit ambient temperature. Komatsu-brand equivalent: Komatsu Genuine Coolant. |
| Fuel tank | not documented for this exact serial range - verify with your dealer | No. 2-D diesel fuel; switch to a winter-blended or No. 1-D diesel below freezing to prevent fuel waxing. |
| Hydraulic system (including tank) | not documented for this exact serial range - verify with your dealer | Anti-wear hydraulic oil, ISO VG46 for normal climates (ISO VG32 in cold weather, ISO VG68 in hot weather). Komatsu-brand equivalent: Komatsu HO. This oil also feeds the hydrostatic travel drive on this loader. |
| Transmission / hydrostatic travel drive | shares the main hydraulic reservoir - no separate transmission oil chamber is documented for this hydrostatic-drive loader | Same anti-wear hydraulic oil as the hydraulic system (see above). |
| Final drives / axles | not applicable - wheels are driven by hydrostatic motors rather than geared final drives with their own oil sump; no separate axle capacity is documented | n/a |
| Grease points (pins, bushings, pivots) | spec only - no bulk reservoir; apply at each fitting per the lubrication schedule | Multipurpose lithium-based EP grease, NLGI 2. Komatsu-brand equivalent: Komatsu Genuine Grease. |
Capacities are refill values from factory literature — always fill to the dipstick/sight gauge, not the number.
Komatsu SK07-1(S/N 3440007-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 SK07-1(S/N 3440007-Up) beyond the schedule
Predictive Maintenance & Fluid Analysis
Hydraulic oil condition is the best predictor of trouble here, since one reservoir feeds both the loader circuit and the hydrostatic travel drive. Sample and check cleanliness at filter-change intervals rather than waiting for sluggish response or hesitation on grade, both classic contamination symptoms. Track engine oil condition and coolant temperature trends on the Yanmar 4TN84 to catch a failing water pump or slipping fan belt early. Watch cold-start behavior over time: gradually harder starting points to injector wear or dropping compression before it strands the machine.
Corrective & Common Repairs
Repair calls mostly trace to three spots: injector or glow-plug wear causing hard cold starts and smoky idle on the 4TN84; a seat safety interlock switch that blocks hydraulics even though the machine is otherwise sound; and clogged or contaminated hydraulic filters producing jerky, inconsistent hydrostatic travel. Bucket cylinder rod seals commonly weep once the machine has real hours on it. On backhoe-equipped units, the added stabilizer and boom circuit leaks more often than the main loader circuit. Rule out corroded electrical connectors before chasing a fuel or engine fault.
Overhaul & Rebuild Points
Plan a top-end look at the 4TN84 (valve clearance, injector spray, compression) once starting or idle quality degrades despite fresh fuel and filters. Loader-arm pivot bushings and bucket linkage pins wear fastest here, since tight-yard work means frequent full-lock turns; check pivots and steering linkage for play with the engine off before it becomes steering slop. A full hydrostatic pump-and-motor rebuild is usually a late-life job, needed only once fluid contamination goes unaddressed. On TLB units, inspect the backhoe mounting frame and stabilizer cylinders for wear from off-pavement digging.
Seasonal & Environment Servicing
Switch to a lighter engine oil (down to SAE 5W-30) and winter-blended diesel before freezing weather to protect the 4TN84's cold-start performance, and confirm the preheat/glow lamp cycles correctly rather than staying lit or never lighting. Match hydraulic oil viscosity to season, since this same fluid also runs the hydrostatic drive and thin summer oil will not protect it in winter. In hot, dusty yards, shorten air filter and grease intervals given tight linkage geometry. Drain fuel tank sediment more often in humid storage to prevent water-related injector damage.
SK07-1(S/N 3440007-Up) common service parts
| Part number | Part | Notes | |
|---|---|---|---|
| 885411417 | Oil Filter Clogging Transmitter | Lubrication service | Check fitment → |
| 885141126 | Glass, Transmission Oil Filter Clogging | Lubrication service | Check fitment → |
| YMR000114 | Filter, Assembly | Scheduled service item | Check fitment → |
| YMR000115 | Element, Assembly | Scheduled service item | Check fitment → |
| YMR000344 | Wrench, Filter | Scheduled service item | Check fitment → |
Always confirm against your machine's serial number — cross-check any part in Heavy Parts AI before ordering.
SK07-1(S/N 3440007-Up) fault codes & troubleshooting
| Code | Meaning | Likely cause | What to do |
|---|---|---|---|
| Oil pressure warning lamp (red oil-can symbol) | Engine lubrication pressure has dropped below the safe minimum. | Low oil level, clogged oil filter, worn oil pump, or a faulty pressure sender. | Stop the engine at once. Check oil level and filter condition before restarting. |
| Battery charge warning lamp (red battery symbol) | Alternator output has dropped and the battery is discharging. | Loose or broken drive belt, worn alternator brushes or regulator, or a wiring fault. | Check belt tension and battery terminals. Test alternator output with a meter. |
| Coolant temperature warning lamp or red gauge segment | Engine coolant temperature has exceeded the safe operating range. | Low coolant, blocked radiator fins, slipping fan belt, or a stuck thermostat. | Stop and idle down, let the engine cool, then check coolant level and radiator for blockage. |
| Preheat/glow indicator lamp | Intake air preheat circuit is active ahead of a cold start. | Normal on cold starts; a lamp that stays lit or never lights points to a preheat relay or wiring fault. | Wait for the lamp to go out before cranking. If it never lights on a cold start, check the preheat relay and wiring. |
| Parking brake engaged lamp | Parking brake is applied. | Brake left on, or a stuck or misadjusted brake switch. | Release the parking brake before driving. If the lamp stays lit with the brake released, check the switch and linkage. |
Codes and remedies are general guidance for this model family — always confirm with diagnostic tooling and your dealer before major repairs.
SK07-1(S/N 3440007-Up) attachments & work tools
General-purpose buckets
The standard front-mounted GP/dirt bucket is the primary work tool for this compact wheel-loader class. Nominal capacity runs roughly 0.3-0.4 m3 (varies by configuration/series across the SK07 family), sized for general loading, stockpiling and truck-loading duty rather than heavy quarry work.
Pallet forks
A fork frame or carriage can replace the front bucket for palletized material handling and general yard work. This is a common option across compact wheel loaders of this size class rather than a factory-standard fitment.
Loader-backhoe (rear excavator) attachment
Factory parts documentation for this serial-range family lists an optional rear backhoe/excavator unit that converts the machine into a tractor-loader-backhoe (TLB) configuration, offered across several serial-range variants of the SK07-1 line rather than as a running factory-standard fitment. Exact digging specs are not documented for this exact serial range - verify the specific backhoe kit against the parts book with your dealer.
Attachment mounting / coupler system
Work tools on this vintage compact loader mount via pin-on/bolt-on frames rather than a hydraulic quick-coupler. Changeover between bucket, forks or the backhoe unit is a manual pin-and-linkage swap rather than a cab-operated quick-hitch.
Auxiliary hydraulics for rear/backhoe attachment
Fitting the rear backhoe option requires its own hydraulic circuit and stabilizer legs tied into the loader's main hydraulic pump. The base front-loader configuration does not carry a rear auxiliary circuit without this kit installed.
All SK07-1(S/N 3440007-Up) assemblies by section
Every catalogued assembly group for the Komatsu SK07-1(S/N 3440007-Up). Open an assembly to preview the parts inside — full OEM part numbers are available in Heavy Parts AI.
Engine
Komatsu : Sk07-1(S/N 3440007-Up) : Engine : Air Intake Manifold
| YM***68 | Bend | 1 |
| YM***88 | Heater | 1 |
| YM***89 | Gasket | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Engine : Cooling Water System
| YM***17 | V-Belt | 1 |
| YM***08 | Screw | 1 |
| YM***08 | Rubber | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Engine : Crankshaft And Piston
| YM***97 | Parallel Pin | 1 |
| YM***03 | Bushing (Repair Part) | 4 |
| YM***54 | Ring, Snap | 8 |
Komatsu : Sk07-1(S/N 3440007-Up) : Engine : Cylinder Block
| 87***06 | Motor, Assembly | 1 |
| YM***78 | Cylinder Block, Assembly | 1 |
| YM***39 | Plug | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Engine : Cylinder Head
| YM***08 | Screw | 7 |
| YM***65 | Seal, Valve Exhaust | 4 |
| YM***52 | Guide Valve | 4 |
Komatsu : Sk07-1(S/N 3440007-Up) : Engine : Engine Stop Device
| YM***48 | Tie-Rod | 1 |
| YM***26 | Support | 1 |
| YM***19 | Clamp | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Engine : Exhaust Manifold
| YM***52 | Gasket | 1 |
| YM***14 | Manifold, Exhaust | 1 |
| YM***53 | Nut | 2 |
Komatsu : Sk07-1(S/N 3440007-Up) : Engine : Flywheel Housing And Oil Sump
| YM***08 | Screw | 4 |
| YM***99 | Support | 2 |
| YM***97 | Parallel Pin | 4 |
Komatsu : Sk07-1(S/N 3440007-Up) : Engine : Fuel Injection Line
| YM***39 | Pipe | 1 |
| YM***13 | Ring, Nut | 4 |
| YM***99 | Screw | 2 |
Komatsu : Sk07-1(S/N 3440007-Up) : Engine : Fuel Injection Pump
| YM***29 | Plug | 1 |
| YM***37 | Locking, Rack | 1 |
| YM***87 | Fuel Injection Gear | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Engine : Fuel Line
| YM***75 | Gasket | 2 |
| YM***61 | Pipe | 3 |
| YM***00 | Plug | 2 |
Komatsu : Sk07-1(S/N 3440007-Up) : Engine : Gasket Set
| YM***65 | Seal, Valve Exhaust | 4 |
| YM***82 | O-Ring | 3 |
| YM***46 | Fuel, Wrench, Strainer | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Engine : Gear Housing
| YM***96 | Pipe L=18 | 2 |
| YM***07 | Screw | 6 |
| YM***25 | Nut | 3 |
Komatsu : Sk07-1(S/N 3440007-Up) : Engine : Generator
Komatsu : Sk07-1(S/N 3440007-Up) : Engine : Governor
| YM***26 | Spring | 1 |
| YM***59 | Screw | 1 |
| YM***31 | Nut | 2 |
Komatsu : Sk07-1(S/N 3440007-Up) : Engine : Lubricating Oil Pump
| YM***94 | Dipstick | 1 |
| YM***74 | Gasket | 2 |
| YM***73 | Oil Pressure Transmitter | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Engine : Starter Motor
| YM***05 | Bearing (1) | 1 |
| YM***30 | Shaft | 1 |
| YM***31 | Kit, Stop Set, Pinion | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Engine : Timing Gear And Camshaft
| YM***85 | Bushing | 1 |
| YM***07 | Screw | 2 |
| YM***59 | Bearing, Thrust | 1 |
Escavator E31 (From Serial No. 3440007 To 3441484)
Komatsu : Sk07-1(S/N 3440007-Up) : Escavator E31 (From Serial No. 3440007 To 3441484) : Bucket
Komatsu : Sk07-1(S/N 3440007-Up) : Escavator E31 (From Serial No. 3440007 To 3441484) : Bucket Control Cylinder
| 50***01 | Bushing | 1 |
| 80***24 | Nut | 1 |
| 85***62 | Kit, Gasket | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Escavator E31 (From Serial No. 3440007 To 3441484) : Control Valve (1/3)
| 80***92 | Screw | 1 |
| 80***98 | Screw | 4 |
| 80***09 | Nut (Version B) | 8 |
Komatsu : Sk07-1(S/N 3440007-Up) : Escavator E31 (From Serial No. 3440007 To 3441484) : Control Valve (2/3)
| 80***94 | Screw | 8 |
| 80***98 | Screw | 8 |
| 84***17 | Cap | 2 |
Komatsu : Sk07-1(S/N 3440007-Up) : Escavator E31 (From Serial No. 3440007 To 3441484) : Control Valve (3/3)
| 80***94 | Screw | 8 |
| 80***98 | Screw | 8 |
| 84***07 | Plug | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Escavator E31 (From Serial No. 3440007 To 3441484) : Dipper Control Cylinder
| 80***24 | Nut | 1 |
| 85***76 | Kit, Gasket | 1 |
| 86***07 | Fitting (Except Germany) | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Escavator E31 (From Serial No. 3440007 To 3441484) : Excavation Group
| 20***67 | Arm | 1 |
| 20***68 | Arm | 1 |
| 50***96 | Pin | 2 |
Komatsu : Sk07-1(S/N 3440007-Up) : Escavator E31 (From Serial No. 3440007 To 3441484) : Excavation Group Hydraulic System
| 80***08 | Nut (With Stabilizers Only) | 1 |
| UE***21 | Hose | 1 |
| UE***30 | Pipe | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Escavator E31 (From Serial No. 3440007 To 3441484) : Fixed Frame And Sliding Plate
| 50***62 | Washer | 2 |
| 50***07 | Piston | 4 |
| 80***65 | Bolt | 4 |
Komatsu : Sk07-1(S/N 3440007-Up) : Escavator E31 (From Serial No. 3440007 To 3441484) : Hydraulic Piping Hammer (1/2)
| 20***50 | Plug | 1 |
| 20***70 | Plug (Only For Disconnecting Hammer) | 1 |
| 20***48 | Coupling, Assembly. (For Hammer On Plate And On Excavator) | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Escavator E31 (From Serial No. 3440007 To 3441484) : Hydraulic Piping Hammer (2/2)
| 50***06 | Bushing | 4 |
| 50***96 | Pin | 2 |
| 50***14 | Union | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Escavator E31 (From Serial No. 3440007 To 3441484) : Lifting Control Cylinder
| 80***24 | Nut | 1 |
| 85***77 | Kit, Gasket | 1 |
| 86***07 | Fitting (Except Germany) | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Escavator E31 (From Serial No. 3440007 To 3441484) : Main Valve Control Hydraulic System
| 20***51 | Coupling, Assembly. (For Hand Hammer) | 1 |
| 20***52 | Fitting (For Hand Hammer) | 1 |
| 20***53 | Body (For Hand Hammer) | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Escavator E31 (From Serial No. 3440007 To 3441484) : Main Valve Element For Hammer
| 80***92 | Screw | 4 |
| 80***98 | Screw | 4 |
| 80***09 | Nut (Version B) | 8 |
Komatsu : Sk07-1(S/N 3440007-Up) : Escavator E31 (From Serial No. 3440007 To 3441484) : Rotation Group
| 20***69 | Housing | 1 |
| 80***23 | Bolt | 12 |
| 80***47 | Screw | 4 |
Komatsu : Sk07-1(S/N 3440007-Up) : Escavator E31 (From Serial No. 3440007 To 3441484) : Sliding Plate Hydraulic System With Hydraulic Lock
| 50***10 | Union | 1 |
| 50***44 | Union | 4 |
| 50***08 | Elbow (For Hydraulic Lock) | 2 |
Komatsu : Sk07-1(S/N 3440007-Up) : Escavator E31 (From Serial No. 3440007 To 3441484) : Stabilizers Control Cylinder
| 80***18 | Nut | 1 |
| 86***07 | Fitting (Except Germany) | 1 |
| U2***3A | Cap | 1 |
Excavator E28 (From Serial Number 3440007 To 3441484)
Komatsu : Sk07-1(S/N 3440007-Up) : Excavator E28 (From Serial Number 3440007 To 3441484) : Bucket (Tooth With Bolts Version)
| 20***85 | Bucket, L=300 mm | 1 |
| 20***86 | Bucket, L=400 mm | 1 |
| 20***87 | Bucket, L=250 mm | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Excavator E28 (From Serial Number 3440007 To 3441484) : Bucket (Welded Tooth Version)
| 20***30 | Bucket, L=250 mm | 1 |
| 20***40 | Bucket, L=300 mm | 1 |
| 20***50 | Bucket, L=400 mm | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Excavator E28 (From Serial Number 3440007 To 3441484) : Bucket Control Cylinder
| 20***64 | Cylinder, Assembly | 1 |
| 80***24 | Nut | 1 |
| 85***18 | Kit, Gasket | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Excavator E28 (From Serial Number 3440007 To 3441484) : Control Valve (2/3)
| 80***94 | Screw | 8 |
| 80***98 | Screw | 8 |
| 84***17 | Cap | 2 |
Komatsu : Sk07-1(S/N 3440007-Up) : Excavator E28 (From Serial Number 3440007 To 3441484) : Dipper Control Cylinder
| 80***24 | Nut | 1 |
| 85***18 | Kit, Gasket | 1 |
| 86***07 | Fitting (Except Germany) | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Excavator E28 (From Serial Number 3440007 To 3441484) : Excavation Group
| 50***95 | Pin | 2 |
| 80***82 | Bolt | 10 |
| 80***24 | Screw | 2 |
Komatsu : Sk07-1(S/N 3440007-Up) : Excavator E28 (From Serial Number 3440007 To 3441484) : Excavation Group Hydraulic System
| 80***08 | Nut (With Stabilizers Only) | 1 |
| UE***09 | Hose | 1 |
| UE***07 | Hose | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Excavator E28 (From Serial Number 3440007 To 3441484) : Fixed Frame And Sliding Plate
| 50***62 | Washer | 2 |
| 80***65 | Bolt | 4 |
| 80***13 | Bolt | 2 |
Komatsu : Sk07-1(S/N 3440007-Up) : Excavator E28 (From Serial Number 3440007 To 3441484) : Hydraulic Main Valve (1/3)
| 80***92 | Screw | 1 |
| 80***98 | Screw | 4 |
| 80***09 | Nut (Version B) | 8 |
Komatsu : Sk07-1(S/N 3440007-Up) : Excavator E28 (From Serial Number 3440007 To 3441484) : Hydraulic Main Valve (3/3)
| 80***94 | Screw | 8 |
| 80***98 | Screw | 8 |
| 84***07 | Plug | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Excavator E28 (From Serial Number 3440007 To 3441484) : Hydraulic Piping Hammer (1/2)
| 20***50 | Plug | 1 |
| 20***70 | Plug (Only For Disconnecting Hammer) | 1 |
| 20***48 | Coupling, Assembly. (For Hammer On Plate And On Excavator) | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Excavator E28 (From Serial Number 3440007 To 3441484) : Hydraulic Piping Hammer (2/2)
| 50***02 | Bushing | 1 |
| 50***03 | Bushing | 1 |
| 50***04 | Bushing | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Excavator E28 (From Serial Number 3440007 To 3441484) : Lifting Control Cylinder
| 80***24 | Nut | 1 |
| 85***19 | Kit, Gasket | 1 |
| 86***07 | Fitting (Except Germany) | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Excavator E28 (From Serial Number 3440007 To 3441484) : Main Valve Control Hydraulic System
| 20***51 | Coupling, Assembly. (For Hand Hammer) | 1 |
| 20***52 | Fitting (For Hand Hammer) | 1 |
| 20***53 | Body (For Hand Hammer) | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Excavator E28 (From Serial Number 3440007 To 3441484) : Main Valve Element For Hammer
| 80***92 | Screw | 4 |
| 80***98 | Screw | 4 |
| 80***09 | Nut (Version B) | 8 |
Komatsu : Sk07-1(S/N 3440007-Up) : Excavator E28 (From Serial Number 3440007 To 3441484) : Rotation Group
| 20***07 | Housing | 1 |
| 20***11 | Rotation Group, Assembly | 1 |
| 80***94 | Bolt | 12 |
Komatsu : Sk07-1(S/N 3440007-Up) : Excavator E28 (From Serial Number 3440007 To 3441484) : Sliding Plate Hydraulic System With Hydraulic Lock
| 50***10 | Union | 1 |
| 50***08 | Elbow (For Hydraulic Lock) | 2 |
| 50***17 | Union | 2 |
Komatsu : Sk07-1(S/N 3440007-Up) : Excavator E28 (From Serial Number 3440007 To 3441484) : Stabilizers Control Cylinder
| 80***18 | Nut | 1 |
| 86***07 | Fitting (Except Germany) | 1 |
| U2***3A | Cap | 1 |
Excavator E30 (From Serial Number 3441491-)
Komatsu : Sk07-1(S/N 3440007-Up) : Excavator E30 (From Serial Number 3441491-) : Bucket (Tooth With Bolts Version)
| 20***85 | Bucket, L=300 mm | 1 |
| 20***86 | Bucket, L=400 mm | 1 |
| 20***87 | Bucket, L=250 mm | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Excavator E30 (From Serial Number 3441491-) : Bucket (Welded Tooth Version)
| 20***30 | Bucket, L=250 mm | 1 |
| 20***40 | Bucket, L=300 mm | 1 |
| 20***50 | Bucket, L=400 mm | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Excavator E30 (From Serial Number 3441491-) : Bucket Control Cylinder
| 80***67 | Bolt (Optional) | 2 |
| 80***24 | Nut | 1 |
| 80***08 | Washer (Optional) | 2 |
Komatsu : Sk07-1(S/N 3440007-Up) : Excavator E30 (From Serial Number 3441491-) : Control Valve (2/3)
| 80***94 | Screw | 8 |
| 80***98 | Screw | 8 |
| 84***17 | Cap | 2 |
Komatsu : Sk07-1(S/N 3440007-Up) : Excavator E30 (From Serial Number 3441491-) : Dipper Control Cylinder
| 80***24 | Nut | 1 |
| 85***18 | Kit, Gasket | 1 |
| 86***07 | Fitting (Except Germany) | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Excavator E30 (From Serial Number 3441491-) : Excavation Group
| 80***82 | Bolt | 10 |
| 80***24 | Screw | 2 |
| 80***92 | Dowel | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Excavator E30 (From Serial Number 3441491-) : Excavation Group Hydraulic System
| 80***08 | Nut (With Stabilizers Only) | 3 |
| UE***14 | Protection | 1 |
| UE***62 | Hose | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Excavator E30 (From Serial Number 3441491-) : Fixed Frame And Sliding Plate
| 50***62 | Washer | 2 |
| 80***65 | Bolt | 4 |
| 80***13 | Bolt | 2 |
Komatsu : Sk07-1(S/N 3440007-Up) : Excavator E30 (From Serial Number 3441491-) : Hydraulic Main Valve (1/3)
| 80***92 | Screw | 1 |
| 80***98 | Screw | 4 |
| 80***09 | Nut (Version B) | 8 |
Komatsu : Sk07-1(S/N 3440007-Up) : Excavator E30 (From Serial Number 3441491-) : Hydraulic Main Valve (3/3)
| 80***94 | Screw | 8 |
| 80***98 | Screw | 8 |
| 84***07 | Plug | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Excavator E30 (From Serial Number 3441491-) : Hydraulic Piping Hammer (1/2)
| 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 : Sk07-1(S/N 3440007-Up) : Excavator E30 (From Serial Number 3441491-) : Hydraulic Piping Hammer (2/2)
| 50***10 | Union | 1 |
| 50***47 | Union (For Hand Hammer) | 1 |
| 82***20 | Point | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Excavator E30 (From Serial Number 3441491-) : Lifting Control Cylinder
| 80***24 | Nut | 1 |
| 86***07 | Fitting (Except Germany) | 1 |
| 86***04 | Fitting (Only For Germany) | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Excavator E30 (From Serial Number 3441491-) : Main Valve Control Hydraulic System
| 20***51 | Coupling, Assembly. (For Hand Hammer) | 1 |
| 20***52 | Fitting (For Hand Hammer) | 1 |
| 20***53 | Body (For Hand Hammer) | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Excavator E30 (From Serial Number 3441491-) : Main Valve Element For Hammer
| 80***92 | Screw | 4 |
| 80***98 | Screw | 4 |
| 80***09 | Nut (Version B) | 8 |
Komatsu : Sk07-1(S/N 3440007-Up) : Excavator E30 (From Serial Number 3441491-) : Main Valve Support
| 80***46 | Bolt | 8 |
| 80***48 | Bolt | 1 |
| 80***97 | Screw | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Excavator E30 (From Serial Number 3441491-) : Rotation Group
| 20***07 | Housing | 1 |
| 20***11 | Rotation Group, Assembly | 1 |
| 80***94 | Bolt | 12 |
Komatsu : Sk07-1(S/N 3440007-Up) : Excavator E30 (From Serial Number 3441491-) : Sliding Plate Hydraulic System With Hydraulic Lock
| 50***08 | Elbow (For Hydraulic Lock) | 2 |
| 50***17 | Union | 2 |
| 80***82 | Bolt | 12 |
Komatsu : Sk07-1(S/N 3440007-Up) : Excavator E30 (From Serial Number 3441491-) : Stabilizers Control Cylinder
| 80***18 | Nut | 1 |
| 86***07 | Fitting (Except Germany) | 1 |
| U2***3A | Cap | 1 |
Machine And Optional Devices
Komatsu : Sk07-1(S/N 3440007-Up) : Machine And Optional Devices : Accelerator - Fuel System
| 20***44 | Fuel Tank | 1 |
| 20***50 | Plug | 1 |
| 20***57 | Plug, Assembly | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Machine And Optional Devices : Air Filter - Exhaust Silencer
| 33***62 | Muffler | 1 |
| 33***63 | Exhaust Hose | 1 |
| 33***00 | Pipe | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Machine And Optional Devices : Arm - Bucket
| 20***39 | Pushrod | 1 |
| 20***50 | Handle | 1 |
| 31***06 | Plate, Fki | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Machine And Optional Devices : Brake Group
| 33***76 | Link | 1 |
| 33***00 | Block | 1 |
| 33***01 | Union | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Machine And Optional Devices : Bucket Control Cylinder
| 39***49 | Bushing | 1 |
| 39***00 | R.H. Cylinder, Assembly | 2 |
| 39***00 | R.H. Cylinder, Assembly | 2 |
Komatsu : Sk07-1(S/N 3440007-Up) : Machine And Optional Devices : Cabin (1/2) : Unit_01_of_02
| 33***27 | Spacer (For Mounting Safety Valves) | 6 |
| 33***55 | Protection | 1 |
| 33***68 | Operator'S Cab, Assembly | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Machine And Optional Devices : Cabin (1/2) : Unit_02_of_02
| 33***27 | Spacer (For Mounting Safety Valves) | 10 |
| 33***16 | Spacer (Only For Mounting Front Door) | 3 |
| 33***29 | Spacer (For Mounting Front Door) | 6 |
Komatsu : Sk07-1(S/N 3440007-Up) : Machine And Optional Devices : Cabin (2/2)
| 33***63 | Seat Belt, Assembly | 1 |
| 33***66 | Cover | 2 |
| 33***68 | Washer | 4 |
Komatsu : Sk07-1(S/N 3440007-Up) : Machine And Optional Devices : Electrical Components
| 33***55 | Ppc Valve, L.H | 1 |
| 33***58 | Knob | 1 |
| 33***50 | Support | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Machine And Optional Devices : Engine-Pumps Group
| 33***50 | Joint | 1 |
| 33***51 | Flange | 1 |
| 33***64 | Support, R.H | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Machine And Optional Devices : Equipment (Germany Version)
| 33***58 | Support | 1 |
| 80***47 | Bolt | 1 |
| 80***00 | Screw (Only For Germany) | 2 |
Komatsu : Sk07-1(S/N 3440007-Up) : Machine And Optional Devices : Equipment Unloading Kit
| 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 : Sk07-1(S/N 3440007-Up) : Machine And Optional Devices : Final Drive
| 20***46 | Deducer | 2 |
| 50***01 | Tapered Plug | 1 |
| 80***44 | Bolt | 8 |
Komatsu : Sk07-1(S/N 3440007-Up) : Machine And Optional Devices : Frame
| 20***20 | Plug | 2 |
| 33***68 | Shim | 2 |
| 33***51 | Frame | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Machine And Optional Devices : Front Door
| 33***53 | Wiper, Assembly | 1 |
| 33***54 | Door, Assembly | 1 |
| 33***55 | Bracket | 2 |
Komatsu : Sk07-1(S/N 3440007-Up) : Machine And Optional Devices : Hydraulic Main Valve (1/2)
| 80***94 | Screw | 4 |
| 80***98 | Screw | 4 |
| 80***12 | Gasket, Seal | 3 |
Komatsu : Sk07-1(S/N 3440007-Up) : Machine And Optional Devices : Hydraulic Main Valve (2/2)
| 80***94 | Screw | 4 |
| 80***98 | Screw | 4 |
| 84***21 | Control Valve, Assembly | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Machine And Optional Devices : Hydraulic Piping (Bucket Lifting Cylinder) : Unit_03_of_03
| 20***70 | Clamp | 7 |
| 33***92 | Pipe | 2 |
| 33***93 | Pipe | 2 |
Komatsu : Sk07-1(S/N 3440007-Up) : Machine And Optional Devices : Hydraulic Piping (Bucket Lifting Cylinder) : Unit_02_of_03
| 20***70 | Clamp | 7 |
| 33***90 | Pipe | 1 |
| 33***91 | Pipe | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Machine And Optional Devices : Hydraulic Piping (Bucket Lifting Cylinder) : Unit_01_of_03
| 20***30 | Fastener | 7 |
| 33***56 | Pipe | 1 |
| 33***57 | Pipe | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Machine And Optional Devices : Hydraulic Piping (Bucket Tipping Cylinder) : Unit_02_of_03
| 20***70 | Clamp | 2 |
| 33***15 | Retainer | 1 |
| 33***86 | Pipe | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Machine And Optional Devices : Hydraulic Piping (Bucket Tipping Cylinder) : Unit_01_of_03
| 20***30 | Fastener | 2 |
| 33***15 | Retainer | 1 |
| 33***52 | Pipe | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Machine And Optional Devices : Hydraulic Piping (Bucket Tipping Cylinder) : Unit_03_of_03
| 20***70 | Clamp | 2 |
| 33***15 | Retainer | 1 |
| 33***95 | Pipe | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Machine And Optional Devices : Hydraulic Piping (Delivery And Return Line) (1/2) : Unit_02_of_02
| 20***70 | Plug (Only For Disconnecting Hammer) | 2 |
| 20***90 | Pressure Take-Up | 1 |
| 33***77 | Pipe | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Machine And Optional Devices : Hydraulic Piping (Delivery And Return Line) (1/2) : Unit_01_of_02
| 20***70 | Plug (Only For Disconnecting Hammer) | 2 |
| 20***90 | Pressure Take-Up | 1 |
| 39***72 | Hose | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Machine And Optional Devices : Hydraulic Piping (Delivery And Return Line) (2/2) : Unit_01_of_03
| 20***40 | Indicator Oil Level | 1 |
| 20***72 | Support | 1 |
| 33***02 | Valve | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Machine And Optional Devices : Hydraulic Piping (Delivery And Return Line) (2/2) : Unit_02_of_03
| 20***40 | Indicator Oil Level | 1 |
| 20***72 | Support | 1 |
| 33***02 | Valve | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Machine And Optional Devices : Hydraulic Piping (Delivery And Return Line) (2/2) : Unit_03_of_03
| 20***40 | Indicator Oil Level | 1 |
| 20***72 | Support | 1 |
| 33***02 | Valve | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Machine And Optional Devices : Hydraulic System Boom Loader Kit
| 20***51 | Coupling, Assembly. (For Hand Hammer) | 1 |
| 20***52 | Fitting (For Hand Hammer) | 1 |
| 20***53 | Body (For Hand Hammer) | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Machine And Optional Devices : Instrumentation
| 20***28 | Dashboard | 1 |
| 35***53 | Wrench | 2 |
| 80***60 | Screw | 4 |
Komatsu : Sk07-1(S/N 3440007-Up) : Machine And Optional Devices : Lifting Control Cylinder
| 39***00 | Cylinder, Assembly | 2 |
| 39***13 | Piston | 1 |
| 39***02 | Cylinder | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Machine And Optional Devices : Pedals Locking
| 20***21 | Stopper | 1 |
| 33***02 | Spring | 1 |
| 33***63 | Safety Bar | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Machine And Optional Devices : Pedals Unit
| 20***22 | Central, Pedal | 1 |
| 20***23 | Pedal, L.H | 1 |
| 20***05 | Support, R.H | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Machine And Optional Devices : Radiator - Heat Excangeur Group
| 20***87 | Support, Tank | 1 |
| 33***57 | Radiator, Assembly | 1 |
| 33***81 | Protection, Fan | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Machine And Optional Devices : Rear Door
| 33***52 | Support | 1 |
| 33***53 | Striker | 1 |
| 33***02 | Spring | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Machine And Optional Devices : Road Homologation - Work Light (1/2)
| 33***03 | Support (Version A) | 1 |
| 33***17 | Plate | 2 |
| 33***13 | Plate | 2 |
Komatsu : Sk07-1(S/N 3440007-Up) : Machine And Optional Devices : Road Homologation - Work Lights (2/2)
| 20***24 | Chain (With Stabilizers Only) | 2 |
| 20***06 | Protection For Bucket L=1420 | 1 |
| 33***00 | Support | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Machine And Optional Devices : Safety Valve (1/2)
| 33***03 | Support | 2 |
| 33***54 | Pipe | 1 |
| 33***00 | Plate | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Machine And Optional Devices : Safety Valve (2/2) : Unit_02_of_02
| 33***03 | Support | 2 |
| 33***51 | Pipe | 1 |
| 33***55 | Pipe | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Machine And Optional Devices : Safety Valve (2/2) : Unit_01_of_02
Komatsu : Sk07-1(S/N 3440007-Up) : Machine And Optional Devices : Self-Levelling Valve : Unit_02_of_02
| 84***64 | Valve, Assembly | 1 |
| 84***25 | Valve | 1 |
| 84***26 | O-Ring | 2 |
Komatsu : Sk07-1(S/N 3440007-Up) : Machine And Optional Devices : Self-Levelling Valve : Unit_01_of_02
| 84***01 | Valve, Assembly | 1 |
| 84***01 | Plug | 3 |
| 84***02 | Spring | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Machine And Optional Devices : Shovel Connection Devices
| 33***54 | Support | 2 |
| 33***06 | Lever Extension | 2 |
| 33***51 | R.H. Lock | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Machine And Optional Devices : Stabilizer Foot
| 20***63 | Bracket | 1 |
| 33***51 | L.H. Stabilizator Foot | 1 |
| 33***52 | R.H. Stabilizator Foot | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Machine And Optional Devices : Stabilizers Foots Hydraulic System
| 33***50 | Support | 1 |
| 33***60 | Pipe | 2 |
| 33***61 | Pipe | 2 |
Komatsu : Sk07-1(S/N 3440007-Up) : Machine And Optional Devices : Tools - Mark Plate
| 30***38 | Plate ?Fai Komatsu? | 2 |
| 33***06 | Plate, Max. Speed (Only For Germany) | 3 |
| 33***54 | Tools Bag | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Machine And Optional Devices : Transmission
| 20***46 | Deducer | 2 |
| 33***52 | Connecting Rod | 2 |
| 33***53 | Chain | 2 |
Komatsu : Sk07-1(S/N 3440007-Up) : Machine And Optional Devices : Transmission Hydraulic Motor
| 84***68 | Hydraulic Motor | 2 |
| 84***24 | Bearing | 1 |
| 84***25 | Bearing | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Machine And Optional Devices : Transmission Hydraulic Pump (1/2)
| 84***73 | Pump, Assembly | 1 |
| 84***40 | O-Ring | 1 |
| 84***44 | O-Ring | 2 |
Komatsu : Sk07-1(S/N 3440007-Up) : Machine And Optional Devices : Transmission Hydraulic Pump (2/2)
| 84***73 | Pump, Assembly | 1 |
| 84***40 | O-Ring | 1 |
| 84***44 | O-Ring | 2 |
Komatsu : Sk07-1(S/N 3440007-Up) : Machine And Optional Devices : Transmission Hydraulic System
| 33***65 | Pipe | 1 |
| 33***66 | Pipe | 1 |
| 39***73 | Hose | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Machine And Optional Devices : Travel Control Lever
| 33***15 | Bushing | 1 |
| 33***16 | Washer | 2 |
| 33***22 | Bushing | 1 |
Komatsu : Sk07-1(S/N 3440007-Up) : Machine And Optional Devices : Wheels
| 33***11 | Column | 12 |
| 33***50 | Rim (16,5x8,25) | 4 |
| 33***51 | Rim (Optional) | 4 |
Komatsu : Sk07-1(S/N 3440007-Up) : Machine And Optional Devices : Wire Assembly
| 33***58 | Knob | 1 |
| 33***52 | Wiring Harness | 3 |
| 33***03 | Protection | 1 |
SK07-1(S/N 3440007-Up) serial number reference
The SK07-1 identification plate is riveted to the machine frame, typically near the operator's seat or on the rear chassis rail on this class of small Komatsu loader; it stamps the model code (SK07-1) together with the full serial number. This series does not use a short alpha PIN prefix like larger Komatsu machines - the production run is identified by the numeric serial breakpoint itself (e.g. 3440007-Up vs 1001-Up), so match the full serial stamped on the plate against the manual's stated S/N-Up range rather than a 3-letter code.
| Prefix | Identifies | Notes |
|---|---|---|
| 3440007 | SK07-1 - Italy-built production run | Serial breakpoint 3440007-Up marks a distinct production block for the bare SK07-1 model code, built at Komatsu's European (Italy) plant rather than the Japan-built 1001-Up block. Engine fitted is not reliably tied to this specific serial run in available sources - confirm with dealer. |
| 1001 | SK07-1 - Japan-built production run (JPN) | A separate parts listing covers S/N 1001-Up, labeled as the Japan-built block - a different plant and serial series under the same bare SK07-1 model code, distinct from the 3440007-Up Italy run. Parts listings tied to this JPN block point to a 2D94-2 diesel; that engine tie is not documented for the 3440007-Up Italy run. Confirm exact engine and configuration with dealer before assuming a given machine falls in this run rather than 3440007-Up. |
Frequently asked questions
What engine does the Komatsu SK07-1 (S/N 3440007-Up) use?
This serial range uses a Yanmar 4TN84 four-cylinder, direct-injection, liquid-cooled diesel rated at 29 kW (38.9 hp), with mechanical governing and no engine control module or electronic diagnostics. A separate Japan-built SK07-1 population (S/N 1001-Up) uses a different engine and is not part of this serial range.
What is the operating weight of the Komatsu SK07-1 (S/N 3440007-Up)?
Operating weight runs approximately 2,360 kg (5,203 lb), with a rated operating capacity of approximately 634 kg (1,398 lb) and a standard bucket capacity of approximately 0.36 m³ (0.47 cu yd). Figures can vary slightly by configuration, such as backhoe-equipped units.
What replaced the Komatsu SK07-1 in this lineup?
The SK07 nameplate continued with the SK07J-1 and SK07J-2 variants, which run on their own separate serial blocks and are distinct machines from this 3440007-Up run rather than direct drop-in equivalents. Treat any parts or spec claim tied to those variants as unconfirmed for this serial range unless your dealer verifies it.
What SK07-1(S/N 3440007-Up) owners discuss
What's the real-world word on the Yanmar 4TN84 engine in this loader?
Shops that service this engine family call it tough and simple to keep running, but flag a few age-related patterns. Cold starts get harder as hours pile up, usually traced to worn glow plugs, dropping compression, or clogged/worn injectors rather than one single failure point. Some units run smoky at low idle in cold weather, put down to over-cooling at low RPM rather than a combustion fault. The 4TN84 shares its block family with the engine used in Komatsu's own small wheel loader line, so a diesel shop familiar with small Yanmar industrial engines can service this one even though the loader itself is scarce. Injector condition and valve clearance are worth checking on a schedule rather than waiting for a hard-start complaint.
How does the hydrostatic drive behave, and what wears out first?
This class of small hydrostatic loader is sensitive to hydraulic oil condition. Sluggish response, hesitation on a grade, or loss of drive power under load is almost always traced to contaminated or overheated oil rather than an outright pump failure. Jerky or inconsistent travel is more often a clogged filter or a sticking control valve than a worn charge pump. Change hydraulic oil and filters on schedule and the drive tends to outlast most other wear items on the machine; skip it and pump/motor wear accelerates. If drive power loss persists after a fluid and filter service, have your dealer verify charge pressure and pump output before condemning the transmission.
What wear points show up first on the loader arms and bucket linkage?
Pin and bushing wear at the loader arm pivots and bucket linkage is typically the first thing to develop play on a machine this size, especially if it has worked hard in tight spaces where full-lock turns and quick direction changes are routine. The bucket control cylinder is a common spot for rod seal weeping once the machine has some age on it. Cycle the arms and bucket through full travel and watch and listen for clunking or visible play at the pivots. Regreasing intervals matter more on a loader this compact since the linkage geometry runs tighter than on a full-size wheel loader.
Any known electrical or sensor gremlins on this era of small Komatsu-badged loader?
Wiring on a machine this age is simple compared to a modern electronically controlled loader, and most reported gremlins trace back to age rather than design: corroded connectors and grounds causing intermittent no-start conditions or erratic gauge readings, and a tired battery or alternator that gets mistaken for a fuel or glow plug problem. Seat safety interlock switches are a recurring nuisance across this class of small loader, since a failed or misadjusted switch blocks hydraulic function even though the rest of the machine is fine. These are cheap, simple fixes once diagnosed, but worth ruling out before chasing an engine or hydraulic fault that isn't really there.
Does the optional rear backhoe/excavator attachment have its own quirks?
A machine fitted with the rear backhoe option carries an added hydraulic circuit and extra hose runs back to the stabilizer and boom cylinders, and that added plumbing is where leaks most often show up rather than the main loader circuit. Stabilizer cylinder seals are also a wear point on machines that spend a lot of time working off pavement or on hard-packed ground. Confirm the backhoe was delivered and serviced as a matched unit with this chassis: a mismatched or swapped-on backhoe is a known source of fitment and hydraulic-circuit headaches on small European loader-backhoe combinations of this era.
What should you check when buying a used SK07-1 (S/N 3440007-Up)?
Start the engine cold and watch for hard starting, heavy smoke, or a rough idle, all of which point back to injector or compression condition on this engine. Cycle the loader arms and bucket, and the backhoe if fitted, through full travel checking for jerky movement, drift under load, or leaks at hoses and cylinder rods. Check the loader arm and bucket linkage pins for play and inspect the tires for uneven wear. Verify the seat safety interlock actually blocks hydraulic function when unoccupied. Cross-check the hour meter against overall wear: this was a low-production compact build, parts and service records are thin, and a seller who can't produce history is a bigger red flag here than on a mainstream model. Before finalizing a purchase, have your dealer verify hydraulic pump output and relief pressures, since a weak pump is the costliest hidden problem on a machine this size.
Any tire wear patterns typical for this loader class?
As a wheeled machine working tight yards, tire wear runs uneven fast where turning is frequent and tight, the kind of work this compact size is bought for. Look for uneven or feathered tread wear that points to alignment or steering-linkage wear rather than normal use, and check steering linkage for play with the machine stationary and the engine off.
Compiled from owner and technician discussions across the industry — experiences vary by serial range and machine history.
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