Abstract: The present actuator includes an inner cylinder closed at one end by an end cap and concentrically mounted in a reservoir tube. A fluid reservoir is formed between the inner cylinder and the reservoir tube. A piston is slidably mounted in the Y inner cylinder, dividing an interior volume of the inner cylinder into first and second chambers. A hollow piston rod is secured at its lower end to the piston and extends beyond the inner cylinder. A separator tube is mounted on the end cap and extends through the piston and into the piston rod to provide a fluid conduit from the reservoir to an external source of controlled pressurized fluid.