Abstract: A sealing system for a hydraulic actuator is disclosed which is operable to selectively change the frictional sealing force exerted on a piston rod in response to the fluid pressure acting on the sealing system. The sealing system includes a leakage chamber formed in a rod guide surrounding a moveable piston rod which is partially disposed within a working chamber. A first seal member is operable for permitting a predetermined amount of hydraulic fluid to leak from the working chamber to the leakage chamber. The leakage chamber is in fluid communication with a low pressure fluid reservoir. A flow control valve selectively controls the flow of hydraulic fluid from the leakage chamber to the fluid reservoir so as to change the fluid pressure within the leakage chamber. A pressure responsive seal assembly concentrically engages the piston rod intermediate the leakage chamber and an upper end of the hydraulic actuator.