Buying a used excavator: configuration, measured condition and untested functions
Buying a used excavator means checking the exact configuration and measured condition against the work it must do. Obtain a written report covering the undercarriage, working joints, structure, hydraulics and permitted operating tests, with exclusions identified. A low hour reading, neat bucket or one successful digging cycle cannot establish every system’s condition. Configuration matters before any wear comparison: Cat’s current 306 CR specifications, for example, distinguish minimum and maximum operating-weight arrangements that both exclude the bucket. The model name alone therefore cannot settle the mass of an offered excavator and attachments. Record the installed stick, counterweight, track system, coupler, thumb and tools, then obtain the applicable capacity and transport information. Have a competent inspector use the model’s measurement and testing procedures, diagnose significant findings and quote the known work. Compare complete packages for the intended job, with untested functions and unknown repairs kept separate from costs already supported by evidence.
Establish the fitted package when buying a used excavator
Which configuration details should be recorded before judging the offer?
Identify the serial, boom and stick arrangement, counterweight, track or wheeled carrier, blade where fitted and all included tools and connections. Confirm which photographed equipment is included. The assessment and capacity information must match the actual package, including modifications that affect its operation or protective equipment.
Why can the same 306 CR model have different published operating weights?
The Cat 306 CR specification lists a minimum canopy arrangement at 6,410 kg and a maximum canopy arrangement at 7,090 kg, both excluding the bucket, so identify the actual tracks, counterweight and stick before using either published basis to assess an offered machine and attachments. The listed configurations differ by 680 kg.
Can a buyer add an assumed attachment mass to establish transport weight?
An assumed 6,410 kg machine plus an assumed 300 kg attachment totals 6,710 kg arithmetically. That is not a measured transport mass: first establish the actual machine basis, included equipment, fluids and transport arrangement without double-counting items.
Obtain dimensions and reliable mass evidence for transport. The smallest catalog figure cannot describe every offered package.
Read undercarriage measurements against the intended ground
What belongs in an undercarriage condition report?
For the fitted system, record component identities, measurements, applicable new and replacement references, track-frame condition and hardware findings. Record findings component by component. A seller’s single percentage or photograph cannot establish the complete replacement scope, so obtain an itemized estimate linked to the findings.
Is a wider track shoe automatically a better used-machine package?
Cat’s excavator undercarriage guidance links selection to ground, impacts, attachments and slopes, and warns about wide shoes under strong underfoot conditions. Match the fitted shoes to the approved combination and ground. Width alone cannot establish suitability, reduced wear or better performance for every job.
Commission joint, structural and operating assessments
How should boom, stick and swing movement be assessed?
Use competent personnel, the model’s prescribed support and measurement procedure, and the relevant limits. Locate and measure movement under the specified conditions. Do not push on a suspended counterweight, place hands in moving joints or improvise a test that bypasses the specified isolation and support requirements.
What evidence is needed for structural repairs or modified equipment?
Request the repair or modification history, applicable approval and assessment of the affected structure and protective equipment. A weld needs its own history and assessment. Record inaccessible areas and unresolved findings so a fresh finish does not conceal the further examination needed before the offered machine can be assessed for the job.
Does a cold start identify the cause of smoke or difficult starting?
Record ambient conditions and the actual starting state. Note warnings and symptoms during the authorized test.
Those observations can guide diagnosis, but they do not isolate every fuel, electrical, compression or other fault. A warm demonstration can also leave relevant starting conditions untested; obtain the appropriate investigation before pricing one guessed component as the cure.
How should hydraulic and travel tests be compared with acceptance criteria?
Because combined-function behavior can depend on the fitted control arrangement, record attachment, mode, temperature and load under the manufacturer’s test method before comparing results with that model’s acceptance criteria or diagnosing a slower movement as pump failure. Retain the test conditions with the finding.
Read the report and compare the acquisition costs
| Offer | Purchase | Known work | Delivery | Subtotal |
|---|---|---|---|---|
| A | $35,000 | $8,000 | $2,000 | $45,000 |
| B | $41,000 | $1,000 | $2,000 | $44,000 |
What detail can a named used-inspection program provide?
Cat’s used-inspection description includes configuration and history review, diagnostic access, measurement tools, photographs and component ratings. Obtain the report and terms for the offered serial. The program description illustrates inspection evidence; it does not confer certification on an unrelated listing or prove that every required test was completed on the machine you viewed.
How does identified repair work change the price comparison?
Assume offer A is $35,000 with $8,000 agreed immediate work and $2,000 delivery, reaching $45,000 before tax and additional charges. Assume offer B costs $41,000 with $1,000 work and $2,000 delivery, reaching $44,000. These are illustrative figures, not repair estimates; the lower asking price becomes $1,000 more on that known-cost basis, before differences in capability and unresolved condition.
Verify the attachment combination and close the evidence gaps
Can an included coupler or thumb be valued without its compatibility evidence?
Identify its model, mounting, hydraulic and control requirements, condition and approval for the excavator’s actual configuration. Match the applicable lifting and operating information, accounting for attachment mass on the stated basis. Physical fit, an auxiliary hose or one cylinder movement does not establish the whole combination’s capacity, locking integrity or suitability for your intended material.
What remains to be resolved after the viewing?
Reconcile the condition report, ownership evidence, service history and written quotations with the job requirements, parts support and transport plan. List unperformed tests and obtain required diagnosis. Choose on the supported package and its remaining uncertainty; an hour reading or a successful bucket movement cannot supply missing structural, hydraulic or attachment evidence.
Use excavator task and access requirements and undercarriage measurements for the offered machine. The buying guides cover inspection and sampling scope and Checking a machine for liens and theft: ownership checks.
Keep the offered configuration with the inspection findings
Inventory the excavator, fitted stick, counterweight, track arrangement, coupler and supplied tools before comparing wear or transport figures. A spare bucket and a fitted thumb are separate items to identify, not evidence that every attachment in the listing is an approved complete installation. Record the relevant serial and attachment identification with the quotation and report.
For the undercarriage, include shoes or track belts, chains where fitted, sprockets, rollers, idlers and retaining components in the appropriate inspection. Obtain the model's measurements and reference limits for the actual track system. Missing hardware, visible leakage or damaged components belong in the findings, but one feature's appearance cannot establish the remaining life or replacement cost of the whole assembly.
Have joint and hydraulic checks performed through the correct methods
Identify the pin joints and the swing system as separate inspection areas. Obtain measured movement and the applicable method and limits rather than attempting a generic bucket-and-counterweight rocking exercise beside an unsupported machine. A noise or visible gap is an observation to investigate.
The report should distinguish a diagnosed bearing or bushing problem from further examination still required.
Agree the permitted cold-start and functional tests before the visit. Retain the starting temperature, operating mode, load and other required test conditions with the result. Include travel and simultaneous hydraulic functions where the inspection scope calls for them.
A cycle time from another model or a brief unloaded demonstration cannot supply a universal pump-condition verdict.
Turn the report into comparable purchase packages
List diagnosed repairs, measured wear, unavailable tests and missing equipment separately. Obtain itemized quotations for known work and identify the support available for unresolved findings. Include the cab, restraint, protective equipment, coupler locking and controls in their appropriate assessment rather than treating the digging cycle as a complete inspection.
Compare that finished scope with another offered machine using the same task and attachment requirements. A low meter reading or fresh paint should not replace the records and actual findings, while an unfamiliar symptom should not be assigned a convenient inexpensive cause. The usable comparison is the identified package and the work it still requires.