Maintenance of crawler excavators

Proper maintenance of crawler excavators is crucial for extending equipment lifespan and ensuring operational efficiency. It involves multiple aspects such as daily inspections, regular maintenance, and special maintenance for key components. Below is a detailed maintenance guide:

I. Daily Maintenance (Before and After Daily Operations)

• Clean soil and gravel from the surface of the machine body. Check if the cab glass, lamps are intact, and if the door locks function properly.
• Inspect the crawler and undercarriage: Check the tightness of the crawler (press the middle of the crawler with fingers, a sag of about 20-30mm is appropriate). Check if the track shoes and track links are broken or deformed, and if the track pins are loose. Inspect whether the top rollers, bottom rollers, and idlers rotate smoothly, and if there is any oil leakage or abnormal noise.
• For wheeled excavators (ignore this for crawler-type), check the tires: tire pressure, wear condition, and whether there are bulges or cracks.

• Engine oil: Check the dipstick when the engine is cold. The oil level should be between the upper and lower scale lines. If insufficient, add oil of the same model. At the same time, observe if the oil has deteriorated (turned black or contains impurities).
• Coolant: Check the liquid level in the expansion tank. Add coolant when it is below the minimum scale. Avoid adding water (use special coolant to prevent corrosion of the water tank).
• Hydraulic oil: Observe the hydraulic oil tank level gauge to ensure the oil level is within the specified range. Check the color of the hydraulic oil (normally light yellow or amber; if it turns black, it may need to be replaced).
• Fuel: Check the fuel level in the fuel tank. When adding fuel, take care to filter out impurities and avoid mixing in water. Also, check if the fuel filter is clogged.

• Hydraulic system: Check if there is any leakage in hydraulic pipelines and joints, and if the hoses are aged or damaged. After starting the engine, operate various actions (boom, arm, bucket, rotation, travel) and observe if they are smooth, with no abnormal noise or jamming.
• Brake system: Check the effectiveness of the travel brake and parking brake, whether the brake pedal stroke is normal, and if there is any oil leakage.
• Electrical system: Check the battery power (voltage should be above 12V) and whether the electrode posts are corroded. Check if the lights, horn, and instrument panel display are normal.

II. Regular Maintenance (According to Usage Hours or Cycles)

• Replace the fuel primary filter and drain water and impurities from the fuel-water separator.
• Inspect the engine air filter. If there is a small amount of dust on the surface, gently tap to clean it. If severely clogged (e.g., covered with oil and dust), the filter element needs to be replaced.
• Lubricate key articulation points: According to the instructions, apply grease to the joints between the boom and the frame, between the arm and the boom, between the bucket and the arm, etc. Ensure each lubrication point is fully lubricated (avoid omission to prevent increased wear).

• Replace the engine oil and oil filter: Drain the old oil when the engine is warm (to facilitate the discharge of impurities). After replacing the new filter, add new oil to the standard level.
• Inspect the hydraulic oil return filter and suction filter. If there are many impurities on the filter surface, clean or replace them.
• Inspect the cooling system: Clean dust and debris from the surface of the radiator and condenser (use a high-pressure air gun to blow clean, avoid direct flushing with water to prevent circuit failures) to ensure good heat dissipation.

• Replace the hydraulic oil return filter and suction filter. At the same time, check the contamination degree of the hydraulic oil (through professional testing or by observing the color and viscosity; if it turns significantly black and thick, consider replacing the hydraulic oil).
• Check the tightness of the crawler and the wear condition of the track links. If necessary, adjust the tension cylinder (add or release grease). If the track links and track shoes are severely worn (e.g., the tooth thickness is reduced by more than 30%), replace them in time.
• Check the engine valve clearance (required for some models). If there is abnormal noise or power drop, it needs to be adjusted by professionals.

• Completely replace the hydraulic oil: Drain the old hydraulic oil, clean the inside of the hydraulic oil tank (remove impurities settled at the bottom), add new hydraulic oil, and replace all hydraulic oil filters (including return oil, suction oil, pilot filters, etc.).
• Inspect the engine turbocharger (if equipped): Check if the impeller rotates flexibly, if there is any abnormal noise or oil leakage, and if the connecting pipelines are loose.
• Inspect the hydraulic pump and hydraulic motor: Observe if there is abnormal noise, vibration, or leakage during operation. Measure whether the working pressure is within the specified range (requires professional equipment for testing).
• Inspect structural components: Conduct flaw detection (such as visual inspection or magnetic particle inspection) on the welded parts of the boom, arm, frame, etc., to check for cracks. If cracks are found, repair them by welding in time (to avoid fracture due to operation with faults).

III. Special Maintenance for Key Components

• Avoid long-term idling (insufficient fuel combustion during idling easily causes carbon deposition and increases engine wear). During operation, try to keep the engine within the economic speed range (usually 1500-2000 rpm).
• Regularly clean carbon deposits on engine valves (by adding fuel additives or professional cleaning) to prevent power loss and increased fuel consumption caused by poor valve sealing.
• Check the tightness of the engine belt: Press the middle of the belt with fingers, a deflection of about 10-15mm is appropriate. Too loose may cause slipping (resulting in insufficient power generation and poor heat dissipation), and too tight may damage the bearings.

• Strictly use the hydraulic oil of the model specified by the manufacturer. Do not mix hydraulic oils of different brands and models (to avoid chemical reactions that reduce performance).
• When replacing hydraulic oil, replace all relevant filters at the same time and thoroughly clean the oil tank to prevent impurities in the old oil from contaminating the new oil.
• Avoid overloading the hydraulic system: Do not forcefully excavate hard objects (such as rocks, concrete blocks) during operation to prevent damage to hydraulic components due to excessive pressure.

• Avoid long-term travel on sharp stones, steel bars, and other hard objects to prevent the track shoes from being cut. When operating on muddy and soft ground, be careful to avoid crawler slippage and getting stuck (the travel speed can be appropriately reduced).
• Regularly check the oil level and tightness of the crawler tension cylinder. If oil leakage or insufficient tightness is found, add hydraulic oil and repair the seals in time.

• Keep the battery clean. Regularly rinse the electrode posts with hot water (to remove oxides) and apply Vaseline to prevent corrosion. When the equipment is parked for a long time, disconnect the negative pole of the battery (to avoid power loss).
• Check if the wire harness connectors are loose or aged, especially in parts prone to vibration and oil pollution such as the bottom of the cab and the engine compartment, to ensure reliable circuit connections.

IV. Maintenance for Long-Term Storage

1. Park the excavator on a flat and dry site, and place wooden boards under the crawlers (to prevent the crawlers from rusting due to direct contact with the ground).
2. Drain the fuel from the fuel tank (or add fuel stabilizer), close the fuel tank switch. Drain the engine oil and hydraulic oil (if parked for more than 3 months), and apply new grease to all lubrication points.
3. Clean the soil from the bucket, boom, and other parts. Apply anti-rust oil to metal surfaces (such as the bucket edge and track shoes). Cover the cab glass with cloth to prevent dust from entering.
4. Close the cab doors and windows, turn off the main power switch, remove the battery, and place it in a cool and ventilated place (charge it regularly to keep sufficient power).
5. Start the engine once a week (idle for 10-15 minutes) and operate various actions several times (to circulate the hydraulic oil) to prevent parts from rusting and jamming.