Which is a form of leakage that can occur in hydraulic actuators?

• A. Internal leakage
• B. External leakage
• C. Both
• D. None

Answer: (B)

Leakage paths in hydraulic actuators can be internal or external. Internal leakage happens when fluid bypasses the piston seals inside the cylinder, flowing from one side to the other and causing pressure loss or reduced actuator performance without visible seepage outside. External leakage is when fluid escapes to the surrounding environment through worn seals, fittings, or joints, which you can usually see as a leak on the outside of the actuator.

Both forms are possible in real systems, depending on seal wear, pressure, temperature, and assembly quality. External leakage is a clear sign of leakage, but internal leakage can degrade performance even if nothing is dripping. So the most complete understanding is that leakage can be both internal and external.