🔍 Key Concepts

• How a hydraulic pump moves fluid and what happens if there is air or vapor in the fluid stream • The meaning of slippage in pumps versus physical noise and vibration • Why galvanic action is related to corrosion, not normal operating noise

💭 Think About

• Which condition would make a pump sound like it is "pumping rocks"—something causing bubbles or solid impacts? • Is the problem more likely related to fluid properties (air, vapor, pressure) or to metal corrosion or seal leakage? • Which of these terms is commonly associated with low inlet pressure or restricted suction on a pump?

✅ Before You Answer

• Match the symptom: loud knocking / gravel sound with the correct hydraulic term • Confirm which option is tied to vapor bubbles collapsing inside a pump • Eliminate any choice that deals mainly with electrical corrosion or minor internal leakage without severe noise