Cylindrical liner for piston actuator

A hydraulic actuator comprising:

• a. a top plug having at least one inlet port, the top plug having a proximal side with an inlet port bore in fluid connection with the inlet port, the top plug further defining a central axis in a distal to proximal direction and having at least one sealing groove on the proximal side of the top plug, a top plug seal being received in said groove;
• b. an actuator housing centered along the central axis and proximally connected to the top plug, the actuator housing having an inner diameter and an inward facing wall;
• c. a piston sleeve having a distal end and a proximal end, the piston sleeve further having an inner diameter and an inward facing wall and an outer diameter and an outer diameter and an outward facing wall, the outward facing wall abutting the inward facing wall of the actuator housing, the top plug seal abutting the distal end of the piston sleeve;
• d. a piston having a diameter an outward facing wall, a proximal side and a distal side, the outward facing wall abutting or about abutting the inward facing wall of the piston sleeve;
• e. a downstop having a distal side and a proximal side, the distal side abutting the proximal side of the piston and the proximal side abutting a central spring and connected to an operator shaft having a distal end and a proximal end;
• wherein the piston sleeve is replaceable with a different piston sleeve having a different inner diameter and the piston is replaceable with a different piston having a different diameter, the outward facing wall of the different piston abutting the inward facing wall of the piston sleeve.