A piston cylinder device (1) comprising a cylinder (2) with a first and a second end and a guide (6), such that a pressure chamber (8) is formed in the cylinder. A piston (12) is moveable in the pressure chamber (8). The guide (6) is fixedly secured to the cylinder (2) by a lock ring (7). A sealing means (9) is arranged to seal between the guide (6) and an inner wall of a tubular wall (3) of the cylinder (2) to prevent fluid leakage from the pressure chamber (8) to the surroundings. The piston cylinder device (1) is provided with a material weakening zone (13) arranged in the inner wall of the tubular wall (3) of the cylinder (2) axially between the lock ring (7) and the second end (20) of the cylinder (2), the material weakening zone (13) being arranged to be deformed or sheared against the lock ring (7) at a predetermined level of impact of the piston (12) against the guide (6). A leakage gap (14) is arranged to interrupt the sealing means (9) upon deformation or shearing of the material weakening zone (13) such that gas from the pressure chamber (8) is allowed to leave the pressure chamber (8) through said leakage gap (14) to the surroundings.