A brake, namely a pre-assembled brake, for an electric motor in whose housing there can be arranged the brake, wherein the brake can be actuated electromagnetically and - has a coil winding which is provided in a coil core, - has a lining carrier which can be movably arranged, by means of drive toothing providable on a rotor shaft of the electric motor, in a form-locked manner in a circumferential direction and in a linear manner, namely in a rotor axial direction, namely on a rotor shaft of the electric motor comprises - an armature plate, guided in an axial direction by at least one guide part, in particular an armature plate actable upon by spring elements, and - a friction disc, wherein the guide part is detachably connected to the coil core and to the friction disc, namely is screw-connected, and the friction disc is spaced apart from the coil core by means of the guide part, therefore is secured at a predeterminable, fixed distance from the coil core, wherein the guide part is screwed into the coil core until contact of a further shoulder formed at the guide part, wherein the coil core of the brake receives a bearing of the rotor shaft, characterised in that the axial regions covered by the bearing and by the coil winding of the brake overlap or are the same, wherein a hexagon socket is provided at an axial end-region of the guide part so that the guide part can be screwed into a tapped bore of the coil core by means of a hexagonal tool, wherein the guide part has a cutout with an internal thread, so that the friction disc of the brake is screw-connected to the guide part by means of a screw, wherein the friction disc is secured against a shoulder at the outer circumference of the guide part. wherein the brake can be actuated electromagnetically and - has a coil winding which is provided in a coil core, - has a lining carrier which can be movably arranged, by means of drive toothing providable on a rotor shaft of the electric motor, in a form-locked manner in a circumferential direction and in a linear manner, namely in a rotor axial direction, namely on a rotor shaft of the electric motor comprises - an armature plate, guided in an axial direction by at least one guide part, in particular an armature plate actable upon by spring elements, and - a friction disc, - has a coil winding which is provided in a coil core, - has a lining carrier which can be movably arranged, by means of drive toothing providable on a rotor shaft of the electric motor, in a form-locked manner in a circumferential direction and in a linear manner, namely in a rotor axial direction, namely on a rotor shaft of the electric motor comprises - an armature plate, guided in an axial direction by at least one guide part, in particular an armature plate actable upon by spring elements, and - a friction disc, wherein the guide part is detachably connected to the coil core and to the friction disc, namely is screw-connected, and the friction disc is spaced apart from the coil core by means of the guide part, therefore is secured at a predeterminable, fixed distance from the coil core, wherein the guide part is screwed into the coil core until contact of a further shoulder formed at the guide part, wherein the coil core of the brake receives a bearing of the rotor shaft, characterised in that the axial regions covered by the bearing and by the coil winding of the brake overlap or are the same, wherein a hexagon socket is provided at an axial end-region of the guide part so that the guide part can be screwed into a tapped bore of the coil core by means of a hexagonal tool, wherein the guide part has a cutout with an internal thread, so that the friction disc of the brake is screw-connected to the guide part by means of a screw, wherein the friction disc is secured against a shoulder at the outer circumference of the guide part.