How to Buy a Used Komatsu Excavator Over 40 Tonnes: 20 Questions Answered
40-90 tonne used Komatsu excavator buying guide
How to Buy a Used Komatsu Excavator Over 40 Tonnes: 20 Questions Answered
Twenty direct decision blocks for buyers comparing PC400-PC950 used Komatsu excavators by operating weight, construction, quarry or mining duty, truck match, bucket, hot hydraulics, undercarriage, dismantling, shipping and risk-adjusted landed cost.
| Excavator class | Screening operating weight | Representative Komatsu models | Best-fit applications |
|---|---|---|---|
| Heavy construction | About 41-45 t | PC400, PC450 | Major foundations, road cuts, quarry support |
| Heavy production | About 48-60 t | PC490, PC500, PC550, PC600 | Rock excavation, mass cuts, sustained truck loading |
| Large quarry | About 64-70 t | PC650, PC700 | Quarry faces, high-volume loading, heavy attachments |
| Quarry / mining | About 79-93 t | PC800, PC850, PC900, PC950 | Large haul trucks, mining support, continuous production |
These are buying-screen ranges, not universal model weights. Exact operating weight changes with generation, LC undercarriage, boom, arm, bucket, counterweight, track shoes and guarding; verify the serial-specific specification before bucket, lifting or transport decisions.
See how the machine class changes
Compare the physical scale first, then use the questions below to decide whether the extra operating weight will earn its cost.
1. Which 40-90 tonne used Komatsu excavator should I buy for my job?
Buy the lightest Komatsu that can meet the hardest regular digging, lifting and truck-loading target without working at its limit. Use roughly 41-45 tonnes for heavy civil work and quarry support, 48-60 tonnes for sustained rock and mass excavation, 64-70 tonnes for large quarry production, and 79-93 tonnes for mine-scale loading. Moving up a class increases stability and bucket potential, but it also raises fuel, transport, undercarriage and attachment costs. Recommendation: write down material density, required tonnes per hour, truck size, maximum lift and transport route, then choose the lowest PC class that satisfies all five.
2. Should I buy a used Komatsu PC400 or PC450?
Choose a PC400 for the lowest transport and operating burden in the 40-tonne class, and a PC450 when heavier lifting or a larger bucket will be used every shift. Komatsu references put PC400-8 configurations around 41.7-42.6 tonnes and PC450-8 configurations around 44.3-44.8 tonnes. Both fit heavy foundations, road cuts and quarry support, but the PC450's extra mass is valuable only when the job uses it; otherwise it adds fuel and freight cost without enough production return. Recommendation: buy the PC400 for mixed heavy construction and frequent relocation, and the PC450 for denser material, stronger lifting demand or continuous truck loading.
3. Is a PC490/PC500 or PC550/PC600 the better production excavator?
Choose PC490/PC500 for versatile 50-tonne production and PC550/PC600 only when larger buckets and higher shift output will stay fully utilized. A current PC490 reference is about 47.9-50.0 tonnes with 1.12-3.17 cubic metre bucket options, while PC550/600 variants move into the next transport and attachment class. The larger machine can reduce loading cycles in dense material, but it loses the advantage if trucks queue poorly, haul roads slow the fleet or the bucket is only partly filled. Recommendation: buy PC490/500 for mixed quarry and infrastructure work; approve PC550/600 only after a production calculation shows lower cost per tonne.
4. Should a quarry buyer choose a Komatsu PC650 or PC700?
Choose the PC650 when transportability and attachment flexibility matter, and the PC700 when the haul fleet can use its additional production every hour. Komatsu lists PC650LC-11 configurations around 63.7-65.9 tonnes and a representative PC700LC-11 near 69.5 tonnes. The PC650 can be easier to mobilize and still supports large quarry buckets, while the PC700 adds working mass and loading capability but requires a stronger truck, road and service plan. Recommendation: select PC650 for mixed quarry duties and multiple sites; select PC700 for a stable high-volume face with correctly matched haul trucks.
5. When should I buy a PC850 instead of a PC900 or PC950?
Buy a PC850 for large quarry and mass-earthmoving work, and move to the PC900/950 class only for mine-scale output or very large truck matching. Komatsu lists PC850-8R1 configurations around 78.6-79.8 tonnes with 3.40-4.30 cubic metre buckets; the current PC900LC-11 is about 92.6 tonnes with 2.8-6.1 cubic metre options. The 90-tonne class can cut loading passes, but dismantling, cranes, heavy transport and idle cost rise sharply. Recommendation: choose PC850 unless verified truck payload, material density and shift target require the 90-tonne class.
6. How does the correct Komatsu class change between construction, quarry and mining work?
Use 40-50 tonnes for heavy construction, 50-70 tonnes for quarry production, and 80-90 tonnes only for mine-scale loading or exceptional bulk excavation. Construction rewards mobility, controlled lifting and attachment versatility; quarries reward breakout force, rock protection and cost per tonne; mining adds high utilization, larger trucks, planned rebuilds and component-level maintenance. A PC850 that is economical in two-shift quarry loading can be wasteful on intermittent foundations. Recommendation: choose from the dominant duty cycle, not the largest occasional task, and rent or subcontract the rare oversized work.
7. How should I match bucket size and haul trucks before buying?
Target a repeatable truck-loading match of about four to six clean passes without overfilling the bucket or truck. Compare heaped bucket volume, real fill factor and material density rather than nominal cubic metres alone: a bucket suitable for soil can overload the machine in blasted rock. A 40-50 tonne excavator usually pairs with smaller quarry trucks than a 65-90 tonne machine, but site geometry and truck payload decide the correct combination. Recommendation: calculate bucket payload as volume multiplied by density and fill factor, then reject any excavator-truck pair that needs too many passes or exceeds rated payload.
8. Should I choose standard, LC, SE, long-front or demolition configuration?
Choose standard or LC for ordinary digging, SE for severe earthmoving, and a special front only when its dedicated work will dominate the contract. LC undercarriages improve stability and flotation but add transport width and wear parts; SE arrangements prioritize digging force and reinforced work equipment; long-front and demolition machines exchange ordinary bucket force or transport simplicity for reach and protection. A special front priced like a standard machine is not automatically a bargain. Recommendation: buy the serial-specific factory configuration that matches the main job and avoid undocumented front conversions.
9. Which generation is better for export: Dash 7/8, Dash 10 or Dash 11?
Choose the generation your destination workshop can diagnose, supply and legally operate, not automatically the newest dash number. Dash 7/8 machines often have lower entry cost and familiar systems in export markets; Dash 10/11 can improve controls, monitoring and fuel management but may add emissions hardware, sensors and software dependence. A low-hour Dash 11 can create more downtime than a maintained Dash 8 where DEF, diagnostic tools or electronic parts are scarce. Recommendation: buy Dash 7/8 for simpler support markets and Dash 10/11 only after confirming emissions compliance, diagnostic access and parts lead time.
10. How many hours are too many on a 40-90 tonne Komatsu?
For a heavy Komatsu, duty history and component life matter more than the meter alone. Under 6,000 hours is a lower-hour screening band, 6,000-12,000 hours is normal used territory, and above 12,000 hours requires engine, pump, swing, final-drive and undercarriage records. Quarry breaker work, steep travel and abrasive rock can consume life faster than soil loading at the same hours. Rebuilt components can improve value only when invoices and serial details are verifiable. Recommendation: accept high hours only when measured condition, rebuild evidence and price fund the next major component cycle.
11. How do I verify serial number, KOMTRAX data and rebuild history?
Match the frame serial, engine number, monitor hours, KOMTRAX history and rebuild documents before discussing the final price. Compare locations, fault history, service dates and component serials with physical wear on pedals, seat, pins, rollers and bucket linkage. KOMTRAX is useful evidence but does not replace inspection, and a claimed dealer rebuild without invoices, measurements or component numbers should be valued as unverified. Recommendation: put the accepted serial, hours and documented rebuilt components on the purchase contract and stop if identities conflict.
12. What engine and cooling tests must a heavy Komatsu pass?
Require a true cold start followed by at least 45-60 minutes of loaded digging because heavy-machine cooling faults often appear only after heat soak. Compare cranking, smoke, blow-by, oil pressure, coolant temperature, fan response and warning codes before and after work; inspect oil, coolant and filters for fuel, water or metal. A short no-load rev cannot expose a restricted radiator, weak fan drive or engine that overheats under production load. Recommendation: reject the machine or price a verified repair when temperature rises, pressure falls or smoke and contamination continue hot.
13. How should I test pumps and the Komatsu CLSS hydraulic system?
Test cycle speed, force and combined functions with fully warmed hydraulic oil and the actual work attachment. Record boom-up, arm-in, bucket-curl and swing times, then operate boom, arm and swing together while checking pump noise, engine droop, hydraulic temperature, cylinder drift and case-drain evidence. A machine that is quick cold but slow hot may have pump, control-valve or internal leakage risk. Recommendation: require model-correct pressure and cycle measurements on PC500-class and larger machines, and buy only when hot performance remains balanced.
14. How do I inspect swing drives, travel motors and final drives on a large excavator?
Test both travel circuits and the complete swing system hot, then compare left-right speed, noise, temperature and oil condition. Large Komatsu models may use dual swing systems, making unequal braking, delayed response or metal contamination especially expensive. Travel uphill, track straight on level ground, hold on a slope and inspect final-drive plugs; then check swing bearing movement and stopping distance in both directions. Recommendation: choose the machine with matched temperatures and smooth response, or deduct the full quoted component repair rather than a small allowance.
15. How much undercarriage life should remain on a 40-90 tonne Komatsu?
Require measured remaining life for every major undercarriage component because a complete heavy-machine replacement can erase the purchase-price advantage. Measure links, pin and bush wear, rollers, idlers, sprockets, shoes and track sag on both sides; compare uneven wear, welded shoes and roller leakage. Wide shoes lower ground pressure in soft material but can increase twisting stress on hard rock, while narrow shoes improve durability but reduce flotation. Recommendation: buy only with a written measurement report and deduct the complete near-term replacement cost when any system is close to its limit.
16. Which structural repairs or breaker history should make me reject the machine?
Reject unresolved cracks, distorted frames and undocumented boom or arm repairs; accept ordinary bucket and pin wear only at a measured discount. Compare both sides of the boom foot, arm, revolving frame, counterweight area and track frames for fresh paint, stop-drilled cracks, plating and unequal geometry. Breaker and blasted-rock duty can load the front, swing bearing and hydraulic system more severely than soil loading. Recommendation: accept a structural repair only when an independent inspector verifies alignment, weld procedure and remaining strength in writing.
17. Which bucket and ground-engaging tools should I select for rock, clay or bulk soil?
Choose bucket volume from material density and bucket construction from abrasion and impact, not from the largest bucket that fits the pins. General-purpose buckets suit mixed soil, heavy-duty buckets add wear protection for compacted material, and rock buckets use stronger structure and teeth but add dead weight. Oversized buckets reduce stability and overload boom, cylinders and swing components at full reach. Recommendation: verify the serial-specific bucket chart, expected payload and tooth system, then select the smallest reinforced bucket that meets the production target.
18. What must be dismantled and measured before shipping a 40-90 tonne Komatsu?
Plan transport from measured component dimensions and weights before paying a deposit. A 40-50 tonne machine may move with limited dismantling where routes allow, while 65-90 tonne machines can require removal of bucket, arm, boom, counterweight or track components plus cranes and heavy trailers. Komatsu highlights counterweight removal as a transport feature on its current PC900, showing why logistics are part of machine selection. Recommendation: obtain a written dismantling, lifting, loading and reassembly plan with route and port approval before purchase.
19. What evidence is enough to buy a heavy Komatsu remotely?
Do not buy a 40-90 tonne excavator from edited video, clean paint and a meter photo. Require serial and component plates, at least 50 current photos, one continuous cold-to-hot working video, undercarriage measurements, engine and hydraulic oil analysis, fault-code evidence, leak inspection and a live video call. As machine value and transport cost rise, independent inspection becomes cheaper than one missed pump, swing or structural failure. Recommendation: proceed only when identity, hot performance, wear measurements and shipping configuration form one consistent evidence package.
20. What final decision rule should I use for a used heavy Komatsu?
Buy the machine with the lowest verified cost per required tonne moved, not the lowest advertised price. Add machine price, inspection, inland haulage, dismantling, cranes, export loading, freight, insurance, destination charges, tax, reassembly, initial service and a component reserve. Score job and truck match 25 points, engine/hydraulics 25, undercarriage/structure 20, identity and records 10, transport plan 10 and landed cost 10; require at least 80/100 with no unresolved major failure. Recommendation: approve the purchase only when the score, production estimate and repair reserve are written beside competing machines.
Current used Komatsu excavators over 40 tonnes
These 11 current used listings run from PC400 to PC950 class without adding new machines to fill the grid. Confirm serial-specific operating weight, year, hours, front equipment, undercarriage, hot working condition and dismantling cost before selecting a machine.
FAQ: final checks before purchase
Does PC400 mean the excavator weighs exactly 40 tonnes?
No. The PC number identifies a size family. Actual operating weight changes with generation, LC undercarriage, boom, arm, bucket, shoes, counterweight, guarding and special equipment; verify the serial-specific specification.
Is a PC950 still part of the 90-tonne buying class?
It is normally compared in the same upper construction and quarry decision group, but exact weight and transport configuration vary. Treat PC900/950 as a 90-tonne-class decision and verify the actual machine data.
Should I prefer a rebuilt engine or an original low-hour engine?
Prefer the option with the strongest evidence. A documented rebuild with measurements and component serials can be safer than an undocumented low-hour claim; price an unverified rebuild as unknown condition.
Can a 65-90 tonne Komatsu ship by standard container?
No as a complete machine. These excavators normally require RoRo, flat rack, breakbulk or heavy-lift planning with partial dismantling based on measured component dimensions, weights and port rules.
How large should the first-repair reserve be?
Set the reserve from inspection findings and component exposure, not one fixed percentage. A documented 45-tonne machine may need a smaller reserve than an 80-tonne quarry unit with uncertain undercarriage and pump history.
When is a third-party inspection mandatory?
Use one for every remote 40-90 tonne purchase unless your own qualified technician performs equivalent hot testing, measurements, oil sampling, serial verification and transport inspection.
Official specification anchors: Komatsu lists representative PC400-8 configurations around 41.7-42.6 tonnes, PC490LC-11 around 47.9-50.0 tonnes, PC650LC-11 around 63.7-65.9 tonnes, PC850-8R1 around 78.6-79.8 tonnes and PC900LC-11 around 92.6 tonnes. Review the PC400, PC490, PC650, PC850 and PC900 references, then verify the serial-specific configuration.
Send the material, hourly target, truck size, budget and destination port.
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