Bellows is an asymmetrical elastic one or two layer corrugated metallic sheath, which can stretch, twist, shrink or shift under pressure, force or temperature. Bellows has a specific feature. It cracks in the place of continuous bends. Because of this you hear an unpleasant sound and maybe even the smell of exhaust inside the car. The bellows can not be repaired. It must be replaced.

Bellows can be easily welded in place of the old one, but there are may appear a problem when installing insulation covers. To do this, bend them, cut and weld. Also when welding the new bellows it is important to follow the pipes geometry. So, mark two pieces of the pipe with a marker, before and after the bellows in several places. Then attach the new bellows and carefully measure it to fit the old one the pipe not to shorten or lengthen after welding.