Abstract: Apparatus for manufacturing an at least partly tubular body, provided with an elastic sealing ring accomodated in an internal groove in said member. In a moulding cavity of a mould first the tubular member is formed of plastic synthetic material, thereafter an annular cavity is arranged in the mould adjacent the outer surface of the body and subsequently a pressurized thermoplastic deformable material is brought against the inner surface of said body which material is an elastomer at the temperature of its normal use. Thereby the body is forced into the annular cavity and is simultaneously forming the internal groove, which is filled with elastomeric material.