What does the term "hydraulic leakage" refer to?

The term "hydraulic leakage" specifically refers to the loss of hydraulic fluid from the system due to the failure of seals, fittings, or other components. This loss can lead to decreased efficiency of the hydraulic system, as hydraulic fluid is essential for transmitting power and maintaining system pressure. When seals or fittings fail, fluid can escape, which can also result in potential damage to components and reduced performance of hydraulic equipment.

The other options do not accurately define hydraulic leakage. Excessive pressure buildup refers to an increase in pressure within the hydraulic system, which can lead to system failure but is not connected to leakage. An increase in fluid viscosity affects the flow characteristics of the hydraulic fluid but does not imply that any fluid is escaping from the system. Lastly, the radiation of hydraulic fluid is not a recognized term or issue within hydraulic systems; fluids do not radiate but rather flow within the confines of the system components.