Park brake actuator

A park brake actuator, comprising: a housing; a piston comprising a piston rod and a piston head, the piston being provided in the housing; a spring, wherein the spring is arranged between the piston head and one side of the housing; an opening in the housing in which the piston rod is movably inserted; a fluid chamber being provided between the piston head and a side of the housing, wherein fluid is insertable into a fluid space, wherein the piston comprises at least one first guiding element which is adapted to guide the piston rod in the opening, and; at least one first seal between the piston rod and the opening.