How to Evaluate the True Condition of a Used Excavator

1. Visual Inspection (Walk-Around Check)

Undercarriage (UC):

  - Check track chain/sprocket wear (measure pin height; >90% remaining is ideal).  

  - Inspect rollers, idlers, and carrier rollers for cracks/seals leaks.  

  - Measure track tension and look for uneven wear.  

Hydraulic System: 

  - Inspect hydraulic cylinders for **scoring, pitting, or leaks** around rods/seals.  

  - Check hoses and fittings for cracks, bulges, or oil residue.  

Structure: 

  - Look for cracks, welds, or bends in the boom, arm, and bucket linkage.  

  - Inspect the cab frame for damage or rust.  

Attachments & Bucket:

  - Assess teeth, edges, and side cutters for wear/replacement needs.  

  - Check bucket ears and linkage pins for elongation.  

2. Operational Tests

Engine:

  - Start the engine cold: Listen for excessive smoke (blue=oil; black=fuel; white=coolant).  

  - Check throttle response and idle stability.  

Hydraulics:

  - Test all functions (boom, arm, bucket, swing, travel) at MAX RPM.  

  - Listen for unusual noises (whining=air; knocking=pump issues).  

  - Check for drift(e.g., arm dropping overnight indicates seal failure).  

Swing System:

  - Test swing bearing smoothness and listen for grinding.  

  - Check brake engagement.  

Controls & Electronics:

  - Verify joystick responsiveness and safety interlocks.  

  - Test gauges, lights, and monitors.  

3. Documentation & History

Service Records:

  - Verify maintenance logs (fluid/filter changes, parts replacements).  

  - Look for consistent hourly service intervals.  

Usage History:

  - Ask about previous applications (e.g., mining=high stress; landscaping=moderate).  

  - Cross-check meter hours with wear patterns (e.g., seat/pedal wear vs. displayed hours).  

Ownership & Accident History:

  - Confirm no major repairs or structural damage.  

4. Critical Measurements & Tools

Wear Gauges:

  - Use calipers to measure pin/bushing wear (>10% oversize = replacement needed).  

Hydraulic Pressure Test:

  - Check pump/valve performance against OEM specs.  

Oil Analysis:

  - Sample engine/hydraulic oil for contaminants (metal particles = internal wear).  

5. Red Flags to Avoid

- 🚩 **Excessive Welding/Rust:** Indicates structural repairs or neglect.  

- 🚩 **Inconsistent Hours:** Worn pedals/seat but low meter hours suggest tampering.  

- 🚩 **Fluid Contamination:** Milky oil = coolant leak; metallic sheen = component wear.  

- 🚩 **Unresponsive Hydraulics:** Jerky movements or lag signal pump/valve issues.  

Key Questions to Ask the Seller

1. "Why are you selling the excavator?"  

2. "Can you provide full service records?"  

3. "Has any major component been replaced?"  

4. "Are there any known issues needing repair?"  

Final Tip:

"Price should reflect condition – a cheap excavator with hidden flaws will cost more long-term."