Abstract: An adjustment element includes a cylinder; a piston axially movable in the cylinder and having a piston rod; an elastic annular seal between the piston and the one end of the cylinder, the annual seal including inner and outer radially circumferences which sealingly bear against the piston rod and the cylinder, respectively; a ring-shaped supporting element which is between the one end of the cylinder and the annular seal and axially supported by the cylinder, there being at least one of a first annular gap between the supporting element and the piston rod and a second annular gap between the supporting element and the cylinder; and a safety element which fills in the at least one of the first and second annular gaps. The safety element is made of a material with low melting temperature. The annular seal is axially supported by the supporting element and the safety element.