Method of manufacturing an accumulator having plane mounting surfaces

Production of a tubular volume storage unit (1) comprises hydroforming a tubular volume storage unit to form planar surfaces (8) arranged at a distance from each other, inserting through-holes (4) in the planar surfaces, and forming a connection (15) between the planar surfaces and the front surfaces of holding elements (10). An independent claim is also included for a tubular volume storage unit for fuel. Preferred Features: The distances between the planar surfaces corresponds to the distances of the cylinder head bores in the cylinder head of an internal combustion engine. The connection is produced by a capacitor-discharge welding.