An excavator can have a good engine and strong hydraulics but still require major spending if the undercarriage is heavily worn. Before buying a used excavator, inspect the complete track system rather than looking only at the track shoes. Links, pins, bushings, rollers, carrier rollers, idlers, sprockets and track tension all work together, and wear in one area can accelerate wear elsewhere.
Start with a visual inspection of both sides. Look for uneven wear, damaged shoes, loose bolts, leaking rollers, worn sprocket teeth and abnormal track position. Then operate the excavator and check travel, noise and track movement. For a more accurate purchase decision, ask for actual undercarriage measurements and compare them with the correct manufacturer wear limits. This guide explains what overseas buyers should check before purchasing a used excavator from Japan.
Why Undercarriage Condition Matters Before Purchase
The undercarriage supports the excavator's weight and allows the machine to travel across the jobsite.
Major components can include:
- Track shoes
- Track links
- Pins and bushings
- Track rollers
- Carrier rollers
- Front idlers
- Sprockets
- Track adjusters
- Track guards
These components wear together as a system.
Replacing several worn components at the same time can represent a significant additional ownership cost. For that reason, undercarriage condition should influence the value of a used excavator.
Do Not Judge the Undercarriage From Track Shoes Alone
Track shoes are easy to see, so buyers often focus on them first.
However, shoes are only one part of the system.
An excavator may still have acceptable grouser height while the links, bushings, rollers or sprockets are already heavily worn.
The opposite is also possible. Damaged or worn shoes do not automatically mean every internal track component is near replacement.
Inspect the complete system before making a judgment.
Start by Comparing the Left and Right Tracks
Walk around both sides of the excavator before operation.
Compare:
- Track shoe wear
- Link height
- Sprocket condition
- Roller position
- Idler position
- Track sag
- Missing or loose hardware
Large differences between the left and right sides can indicate uneven operating conditions, poor adjustment or different component replacement histories.
Check the Track Shoes
Track shoes contact the ground and provide traction and flotation.
Inspect for:
- Reduced grouser height
- Bent shoes
- Cracked shoes
- Broken edges
- Missing shoes
- Loose shoe bolts
- Missing bolts
- Different shoe types fitted together
Track shoe width also matters.
Wide shoes can improve flotation on soft ground, but unsuitable shoe width on hard or rocky ground can place additional stress on undercarriage components.
Look Closely at Track Shoe Bolts
Loose hardware deserves attention because movement between the shoe and link can damage mounting surfaces.
Look for:
- Loose bolts
- Missing bolts
- Damaged bolt heads
- Elongated mounting holes
- Signs of repeated tightening
Do not assume missing hardware is only a cosmetic problem.
Inspect the Track Links
The links form the track chain and provide the running surface for the rollers.
Look for:
- Reduced rail height
- Uneven rail wear
- Cracks
- Damaged link edges
- Loose or damaged joints
- Abnormal side wear
Visual inspection can identify obvious damage, but remaining wear life is better evaluated with measurements.
Pins and Bushings Are Critical Wear Components
Pins connect the track links, while bushings interact with the drive sprocket.
Inspect for signs such as:
- Dry joints
- Abnormal movement
- Uneven bushing wear
- Cracking
- Oil or grease leakage from sealed joints
- Track pitch elongation
As pins and bushings wear, the effective track pitch can change. This affects how the chain engages with the sprocket.
Track Elongation Cannot Be Judged Accurately by Eye
A chain may look acceptable but still have significant internal wear.
Professional undercarriage inspections can measure track pitch across several links and compare it with manufacturer wear data.
If the excavator is expensive enough to justify a detailed inspection, ask whether measured undercarriage wear information is available.
Inspect the Sprocket Teeth
The drive sprocket transfers travel power into the track chain.
Look for:
- Sharp or pointed teeth
- Uneven tooth profiles
- Cracks
- Broken teeth
- Abnormal side wear
Very pointed teeth can indicate substantial sprocket wear.
However, sprocket appearance should be considered together with bushing and track-chain condition.
Why Sprocket and Bushing Wear Should Be Viewed Together
The sprocket and track bushings repeatedly contact each other during travel.
If their wear patterns no longer match correctly, accelerated wear can occur.
This is why replacing only one worn component without considering the rest of the track system may not provide the expected service life.
Check the Front Idler
The front idler guides the track and forms part of the track-tension system.
Inspect:
- Tread wear
- Side wear
- Cracks
- Oil leakage
- Abnormal movement
- Position inside the track frame
The idler position can also provide clues about track-chain wear and adjustment range.
Pay Attention to Idler Adjustment Position
As the track chain wears and becomes longer, the adjuster may move the idler farther forward to maintain correct tension.
If the idler is already close to the end of its adjustment range, ask why.
This observation alone cannot determine remaining track life, but it is useful when combined with link and pitch measurements.
Inspect the Lower Track Rollers
Lower rollers carry much of the machine's weight.
Check each visible roller for:
- Oil leakage
- Flat spots
- Heavy tread wear
- Flange wear
- Cracks
- Abnormal sideways movement
- Missing or loose mounting hardware
A roller that has stopped rotating can cause additional wear on the track chain.
Check Carrier Rollers Where Fitted
Carrier rollers support the upper section of the track chain on many excavators.
Inspect:
- Rotation
- Leakage
- Surface wear
- Flange condition
- Debris packed around the roller
Mud or debris can interfere with free roller movement.
Oil Leakage Around Rollers and Idlers Deserves Attention
Many rollers and idlers are lubricated and sealed.
Visible leakage may indicate seal problems.
Do not assume every wet area means immediate replacement, but active leakage should be investigated before purchase.
Check Track Tension
Track tension can strongly affect wear.
A track that is too tight can increase stress and accelerate component wear.
A track that is too loose can affect tracking and increase the risk of derailment.
Correct track sag depends on the exact excavator and operating conditions.
Never apply one generic sag measurement to every model.
Use the manufacturer's maintenance manual.
Mud and Working Conditions Can Change Track Tension
Packed mud, clay, sand, snow or stones can effectively tighten the track during operation.
This means track adjustment may need to reflect real operating conditions.
When inspecting a used machine, look for heavy material packed around:
- Rollers
- Idlers
- Track frames
- Sprockets
Heavy packing can also hide wear or damage.
Track Guards and Rock Guards Should Be Checked
Some excavators use track guides or rock guards to help keep the track aligned.
Inspect:
- Bending
- Cracks
- Heavy wear
- Missing bolts
- Missing guards
Damaged guards can also suggest previous operation in rocky or severe conditions.
Check the Track Frame for Structural Damage
Move beyond the replaceable wear components and inspect the structure itself.
Look for:
- Cracks
- Bending
- Heavy corrosion
- Previous welding
- Impact damage
- Damaged mounting areas
Structural track-frame repairs should be evaluated separately from normal wear-part replacement.
Operate the Excavator and Listen
A static inspection should be followed by a travel test where conditions allow.
Listen for:
- Grinding
- Knocking
- Repeated clicking
- Track jumping
- Unusual roller noise
Watch whether the tracks move smoothly through the rollers, idlers and sprockets.
Travel Forward and Reverse
Test both directions.
Some wear symptoms may become easier to notice in reverse.
Compare:
- Left travel speed
- Right travel speed
- Noise
- Track movement
- Machine pull
A machine that consistently pulls to one side may have an undercarriage issue, but travel motors, hydraulics or other systems can also cause this symptom.
Do Not Confuse Travel-System Problems With Undercarriage Wear
Slow travel or poor straight-line tracking can result from several systems.
Possible causes can include:
- Track tension
- Mechanical undercarriage resistance
- Travel motor condition
- Final drive condition
- Hydraulic performance
Do not conclude that a travel motor is defective only because one track appears slower.
Look at Final Drive Areas for Leakage
The final drives power the sprockets.
Inspect around them for:
- Oil leakage
- Damaged housings
- Loose bolts
- Abnormal noise during travel
Final drive condition is a separate mechanical consideration from normal track wear, but the components are located together and should be checked during the same walk-around.
Steel Tracks and Rubber Tracks Need Different Checks
Mini and compact excavators may use rubber tracks instead of steel track chains.
For rubber tracks, inspect:
- Cuts
- Cracks
- Missing tread sections
- Exposed steel cords
- Damage around embedded metal cores
- Uneven wear
- Track tension
A rubber track should not be evaluated using the same wear measurements as a conventional steel track chain.
Ask Whether the Undercarriage Has Been Partially Replaced
A used excavator may contain a mixture of newer and older components.
Examples include:
- New sprockets with older chains
- New track shoes on worn links
- Several replaced rollers
- One newer track assembly
Partial replacement is not automatically negative.
However, the buyer should understand which parts are new, which remain worn and whether components are working together correctly.
Look for Uneven Wear
Uneven wear can provide clues about previous operating conditions.
Compare both sides and different areas of the same track.
Possible patterns include:
- Heavy inside-edge wear
- Heavy outside-edge wear
- One track more worn than the other
- Individual rollers wearing differently
- Uneven grouser wear
The cause should be investigated rather than guessed from the wear pattern alone.
Previous Working Conditions Matter
| Previous Environment | Areas to Check Closely |
|---|---|
| Rock or quarry work | Shoes, links, sprockets, guards and impact damage |
| Sand or abrasive soil | Pins, bushings, links, rollers and sprockets |
| Mud or clay | Track tension, packed material, rollers and idlers |
| Demolition | Track shoes, guards, frame damage and packed debris |
| Frequent slope work | Uneven side wear and track alignment |
| Light urban work | Hours, shoe condition and general wear pattern |
If previous use cannot be confirmed, treat it as unknown.
Operating Hours Do Not Tell You Undercarriage Life
Two excavators with the same operating hours can have very different track wear.
Wear depends strongly on:
- Ground material
- Moisture
- Track tension
- Travel distance
- Travel speed
- Turning technique
- Shoe width
- Cleaning and maintenance
Hours provide context, but physical wear measurements are more useful for estimating remaining undercarriage life.
Measurements Are Better Than Percentage Guesses
Used-machinery listings sometimes describe an undercarriage as “70%” or “80%.”
Ask what that percentage means.
A useful professional inspection may measure:
- Track pitch or chain elongation
- Link height
- Bushing diameter
- Track shoe or grouser height
- Roller wear
- Idler wear
The measurements should be compared with the correct manufacturer wear chart for that exact undercarriage system.
Do not create a remaining-life percentage from appearance alone.
Manufacturer Measurement Systems Provide Better Evidence
Manufacturers use structured undercarriage measurement programs.
For example, Caterpillar uses Custom Track Service to measure and manage wear components.
Komatsu also recommends precise undercarriage wear measurements and periodic inspection to support decisions about pins, bushings, rollers and sprockets.
If an inspection report is available with the used excavator, it can provide more useful information than photographs alone.
Do Not Assume All Components Wear at the Same Rate
A complete undercarriage may contain components at different stages of wear.
For example:
- Track links may still be usable.
- Bushings may be near their wear limit.
- Several rollers may already leak.
- Sprockets may have been replaced recently.
Estimate repair needs component by component before calculating the machine's real purchase value.
Common Undercarriage Red Flags
- Broken or missing track shoes
- Loose track shoe bolts
- Cracked links
- Dry or damaged track joints
- Very pointed sprocket teeth
- Leaking rollers or idlers
- Rollers that do not rotate
- Excessive or uneven track sag
- Idler near the end of adjustment range
- Major left-to-right wear difference
- Damaged track frame
- Abnormal travel noise
One red flag does not automatically make the excavator a bad purchase.
The important question is how much repair is required and whether the purchase price reflects that condition.
A Practical Excavator Undercarriage Checklist
- Track Shoes: Check grouser wear, cracks and bending.
- Shoe Bolts: Look for loose or missing hardware.
- Links: Inspect rail wear, cracks and side wear.
- Pins and Bushings: Check joints, leakage and visible wear.
- Track Pitch: Ask for measurement where available.
- Sprockets: Inspect tooth shape, cracks and damage.
- Idlers: Check wear, leakage and adjustment position.
- Lower Rollers: Check rotation, leakage and flange wear.
- Carrier Rollers: Inspect condition where fitted.
- Track Tension: Compare with manufacturer specification.
- Track Guards: Check bending, wear and missing parts.
- Track Frame: Inspect cracks, repairs and impact damage.
- Final Drives: Look for oil leakage and abnormal noise.
- Travel Test: Test forward and reverse movement.
- Left vs Right: Compare wear and travel behavior.
- Rubber Tracks: Check cords, cracks and tread where applicable.
- Previous Repairs: Identify partially replaced components.
- Operating Hours: Compare hours with actual measured wear.
- Previous Use: Consider terrain and travel conditions.
- Wear Report: Review professional measurements where available.
What Can an Overseas Buyer Check From Photos?
If you cannot inspect the excavator personally, request clear photographs of both complete undercarriages.
Useful images include:
- Full left track
- Full right track
- Track shoe close-ups
- Track links and bushings
- Left and right sprockets
- Front idlers
- Lower rollers
- Carrier rollers
- Track sag
- Track frame
- Final drive areas
A travel video can also help show track movement and abnormal noise.
Photos cannot replace wear measurements, but they can reveal areas that deserve further inspection.
Buying a Used Excavator from Japan
Japanese used machinery can include mini, compact, medium and large excavators with different steel or rubber track systems.
You can check current Japanese used machinery available at EVERYCAR.jp. Inventory changes regularly, so a particular manufacturer, model or undercarriage specification should not be assumed to remain available.
For more information about checking engines, hydraulics and other major machinery systems before purchase, visit the Japanese Used Machinery & Heavy Equipment Guide.
Measure the Undercarriage Before Estimating Its Remaining Value
A useful used-excavator inspection should treat the undercarriage as a complete wear system.
Check the shoes, links, pins, bushings, rollers, idlers and sprockets. Compare the left and right tracks. Check tension, track-frame condition and travel behavior.
Then, when possible, use actual measurements and the correct manufacturer wear limits to estimate remaining service life.
If you are looking for a used excavator from Japan, you can contact EVERY with your preferred manufacturer, model, size, budget and destination. Exact undercarriage specification, component wear and machine condition should be confirmed for each individual excavator before purchase.
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