Abstract: The invention relates to a method for producing a housing (12) for a throttle valve connection piece (10), which housing is to have particularly high dimensional stability. For this purpose, the housing (12), which has a throttle orifice (16) for a throttle valve (20), is produced from plastic (14) by the injection molding method, plastic (14) being partially injected around a metal cylinder (28) which, at least in the region of the throttle valve (20), forms the throttle orifice (16). In this case, before the injection molding method, an expanding mandrel (50) is expanded against the inner face (33) of the metal cylinder (28). During the injection molding method, the inner face (33) of the metal cylinder (28) is supported at least partially by the expanding mandrel (50). After the injection molding method, a reduction in the outer circumference (80) of the expanding mandrel (50) is carried out in order to remove the expanding mandrel (50) from the interior (70) of the metal cylinder (28).