An actuator assembly includes a cylinder disposed in an actuator housing, the cylinder having a cylinder interior is in fluid communication with a source of pressurized fluid. A ram member has a piston head within the cylinder interior, and pressure on the piston head moves the ram member. An end of the ram member acts on a collar having a collar interior, and an end of a rod member is disposed within the collar interior. The rod member is displaceable relative to the collar such that the end of the rod member does not contact the collar. Accordingly, fluid in the cylinder interior acting on the ram member may expand due to thermal expansion without damaging a hard stop at an opposite end of the rod member and without losing system pressure by triggering a relief valve.