Bolt and threaded connection of a brake hose and a brake pipe

A union nut (11) and a threaded connection between a brake hose (3) and a brake line (7) as well as a tool for tightening and loosening the union nut according to the invention are proposed. [0002] The union nut according to the invention allows the transmission of large torques between union nut and tool. Furthermore, the space requirement during assembly is reduced.