Abstract: A method of making a pressurized shock dampening device, and the device so made wherein: a gas-generating, thermally decomposable substance is placed in the gas chamber of the device at the time of its assembly; the device is filled with hydraulic fluid and sealed; and thereafter the device is heated up to the thermal decomposition temperature of the substance to decompose it inside the device so as to increase the pressure in the gas chamber to at least two atmospheres. A preferred device includes a super atomspherically pressurized gas chamber defined by a bladder which is incommunicado the exterior of the device.