Core items of daily maintenance

1. Hydraulic system maintenance

Regularly check the hydraulic oil level and contamination. It is recommended to replace the filter element every 500 hours and the hydraulic oil every 6000 hours.

High-pressure hoses must be replaced every 5 years or 10,000 hours to prevent safety accidents caused by aging and rupture.

Test the main pump flow (such as the standard CX550-C 187.5±5 L/min@50bar). If abnormal, the pump body or regulator needs to be repaired.

2. Engine maintenance

Check the oil and coolant levels daily and adjust the valve clearance every 250 hours (intake 0.3mm/exhaust 0.45mm).

The injection nozzle pressure must be maintained at 17.7MPa, and the injection timing is calibrated to 11° before the top dead center in the cold state.

3. Structural parts and brake system

The slewing bearing clearance exceeds 1.5mm (measured when the load is 20 tons) and needs to be adjusted or replaced immediately.

When the wear reaches 3 mm, the winch brake pads must be replaced. If the brake drift test (zero displacement within 2 minutes) fails, the hydraulic brake valve needs to be repaired.

Periodic professional inspection

Performance test standard

• Travel performance: Tested on a solid and level ground, the 10-meter travel time of the CX700-C fast gear should be 20.9~24.0 seconds. If the deviation exceeds 10%, the travel motor or reduction box needs to be checked.
• Rotation system: The no-load 3-circle rotation time is 40.8~46.7 seconds (CX550-C). The timeout may be due to motor leakage or valve group failure.

Electrical system inspection

Test the functions of safety devices such as torque limiters and overwinding protection, every month. The controller fault code (such as E20 sensor abnormality) needs to be checked according to the manual instructions.

Safety maintenance warning

• High-pressure risk: The pressure must be released before disassembling the hydraulic pipeline to avoid high-pressure oil injection damage.
• Environmental protection requirements: Waste oil, filter elements, etc., need to be stored in a classified manner and handled by professional institutions.
• Prohibition: Unauthorized modification of the safety valve set pressure (such as the main safety valve standard of 29MPa); otherwise, it may cause structural overload.

Hitachi recommends:

• Establish a step-by-step maintenance plan every 500 hours and 2000 hours, and keep inspection records.
• For complex faults (such as abnormal pump control), contact the authorized service provider first to avoid misjudgment and increased losses.