How should hydraulic system leaks be checked during inspection?

• A. With the engine running and hydraulics pressurized to observe leaks.
• B. With the engine off and hydraulics depressurized; inspect hoses, cylinders and fittings for leaks, and operate controls slowly to observe leaks.
• C. Only visually inspect external hoses.
• D. Check leaks after loading a heavy load.

Answer: (B)

To reliably detect hydraulic leaks, first ensure safety by turning the engine off and depressurizing the hydraulic system. With the system not pressurized, carefully inspect hoses, cylinders, and fittings for any signs of leaks, such as wet spots, seepage, or oil accumulation around joints and seals. After the initial visual check, operate the controls slowly to cycle the hydraulics through their normal range. This controlled movement re-pressurizes parts of the system and helps reveal leaks that wouldn’t be visible while the system is stationary. This approach addresses all common leak points—hoses, fittings, and cylinder seals—and avoids the hazards of testing under pressure or relying only on a static inspection.