Abstract: A lubricating seal construction for a pneumatic cylinder (10) includes a lubricating rod seal (40) and lubricating piston seals (27, 29). The rod seal includes a cavity (66) for holding a supply of viscous flowable lubricant. The piston seals include cavities (100) for holding the supply of similar lubricant. Passages (70) extend from the cavity in the rod seal to apertures (72) adjacent an outer surface (52) of a moveable piston rod (30). Passages (104) extend from the cavity in the piston seals to apertures (106) adjacent an inner surface (26) of the cylindrical chamber (24) inside the cylinder. The seals are made from resilient material and are filled with lubricant during assembly of the cylinder. As the cylinder is cycled, lubricant passes from the cavities as required to lubricate the seals and adjacent moving surfaces.