Equal pressure on both sides of a standard cylinder will_______________.

• A. do nothing
• B. cause the cylinder to retract
• C. cause piston leakage
• D. cause the cylinder to extend

Answer: (C)

When the pressures on both sides of a hydraulic cylinder are the same, there is no net force acting on the piston. Movement of the piston happens only when there is a pressure difference across it, which creates a net force that drives extension or retraction against the load. With equal pressure, these forces cancel, so the piston stays in place (the cylinder does nothing movement-wise), assuming there’s no external force or friction to overcome. Piston leakage, meanwhile, isn’t caused by equal pressures—it’s a seal fault that allows fluid to bypass the piston, reducing efficiency or causing loss of containment. So the expected outcome is no movement, not extension, retraction, or leakage caused by the equal pressures.