An elongated fluid actuator arrangement includes a cylinder body comprising a first and second end portion. A piston body comprising a piston force area forming portion and a sleeve portion, which extends through said first and second end portions and exposes first and second outer section outside the cylinder body. A piston rod extends coaxially through said sleeve portion. The arrangement comprises a first and second extendable and contractible cover member each joined to the cylinder body and to the respective sleeve portion outer section.

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.