Abstract: A retrofit tap valve assembly is disclosed for a tap having a tap housing, an axial flow valve seat in the tap housing, a tap spindle adapted to effect sealing engagement between a tap seal and the valve seat, and a spindle housing mounted in the tap housing and mounting the tap spindle for axial movement relative thereto to effect the sealing engagement, the retrofit tap valve assembly including:a longitudinally extending open-ended cylinder 15 member having a plurality of radially disposed apertures 17 extending longitudinally in the walls of the cylinder, the cylinder being adapted to sealingly engage the tap valve seat, anda piston member 16 adapted to be engaged by the tap spindle for axial movement therewith, the piston member including piston sealing means adapted to effect sealing engagement with the walls of the cylinder member.