Troubleshooting Common Faults of Construction‑Machinery Hydraulic Systems With a Hydraulic Tester

•  Pressure: Reflects system load, performance of relief valves and hydraulic pumps
• Flow Rate: Indicates pump output and internal leakage — the most critical indicator for troubleshooting
• Oil Temperature: Detects overheating, excessive leakage and system overload
• Rotational Speed (RPM): Monitors input speed of engine or hydraulic pump
• Most hydraulic failures stem from internal leakage, worn‑out pumps, stuck valves or relief‑valve pressure loss. These hidden defects cannot be identified visually but will show up clearly on pressure‑flow test data.

• Confirm the rated pressure, flow rate and oil temperature range of the tested hydraulic system, and select a hydraulic tester with matching parameters.
• Check that the tester, connecting hoses and quick‑release couplings are undamaged, clean and free of impurities.
• Start the construction‑machinery engine, run the hydraulic system for several minutes to warm up the oil until it reaches normal working temperature.
• Shut down the equipment and relieve all residual pressure inside the hydraulic circuit before connecting the tester.

The tester is connected **in series into the hydraulic circuit**, either at the pump outlet or oil lines of cylinders and motors.

1. Hydraulic oil flows through the built‑in flow sensor to get real‑time flow data;  2. A branch oil circuit feeds the pressure sensor to collect pressure values under different loads;   3. The temperature sensor monitors hydraulic‑oil temperature;   4. Sensor signals are transmitted to the main display unit, showing real‑time readings and pressure‑flow curves;   5. Operators apply load (build‑up pressure) and record data: - Sharp flow drop at rated pressure → worn hydraulic pump, serious internal leakage    - Pressure fails to rise while flow remains normal → faulty relief valve, pressure regulation failure  - Slow cylinder movement with normal pump flow → internal leakage of cylinder or control‑valve malfunction

• Never connect or disconnect the tester when the hydraulic system is under pressure.
• - Do not exceed the maximum rated pressure of the tester, to avoid instrument damage or safety accidents.
• - Watch oil‑temperature changes during testing; stop testing immediately if overheating occurs.