Patent ID: 7234386

Claim:
A hydraulic actuator for a vehicle suspension system which includes a load leveling apparatus and a control valve assembly that operates in response to sensed motion, said hydraulic actuator comprising: a piston; a tubular piston rod attached to the piston; a cylinder within which the piston is slideably received with an end of the tubular piston rod projecting outward from the cylinder, a first chamber and a second chamber defined within the cylinder, a third chamber within the tubular piston rod and separated from the first and second chambers, the cylinder further comprising a first port for exchanging fluid between the first chamber and the control valve assembly, a second port for exchanging fluid between the second chamber and the control valve assembly, and a third port for exchanging fluid between the third chamber and the load leveling apparatus to alter position of the piston in the cylinder; and an interior member attached to the cylinder and extending into the tubular piston rod, wherein the third chamber extends around the interior member which has an end that is exposed in the third chamber.