rings 37 38 against a shoulder 42 formed on the piston rod 24 when assembled a series of passageways 37a 38a 44a through the various component parts are formed in the guide head 22 to provide a damping action in association with lubricating oil within the pressure cylinder 15 although the guide head 22 does not form a sealed engagement with the cylinder wall 32 the passageways 37a 38a 44a also assist in the equalization of gaseous pressure on either side of the guide head 22 a relief opening 47 is formed in a front face 49 of the end cap 44 and communicates with the passageways 37a 38a 44a there is only a minimum amount of lubricating oil within the pressure cylinder 15 however the relief opening 47 provides an opening through which the oil can escape when the piston assembly 20 is in its fully extended position denoted by reference letter b the operation of a gas spring whether or not practicing the present invention is based upon differences in gaseous pressure between the interior portions of the pressure cylinder 15 generally denoted by reference letter a and the air pressure of the surrounding environment normally atmospheric this pressure differential acts upon the cross sectional area of the piston rod 24 as viewed from the interior of the pressure cylinder 15 causing it to move outwardly from the pressure cylinder 15 the conventionally charged gas springs are subject to two types of pressure drop related problems during operation the first leading ultimately to spring failure over time the seals located within the sealed end 18 fail permitting the pressurized gas in the interior portion a to gradually escape from the cylinder 15 failure of the gas spring inevitably follows this is illustrated in fig3.