Abstract: The invention relates to a method and apparatus for charging a hydro-pneumatic reservoir with gas under pressure. The reservoir is positioned between two vertically aligned supporting members, with the oil charging port and gas charging port of the reservoir axially aligned. The supporting member on which the oil charging port is positioned, is vertically adjustable. The gas charging port carries an initially loose fitting bushing with an expander member at its outer end, the bushing permitting flow of gas therearound to permit charging of the reservoir. A force applying member is slidably mounted in the uppermost supporting member such that when gas under pressure is applied, it will cause the force applying member to move upwardly and the gas under pressure will pass around the bushing into the reservoir to charge the latter.