A tank closure that includes a first tank closure member, a second tank closure member, and a bias member having a spring force to brace the second tank closure against the first tank closure member. The first tank closure member has a first stop member, while the second tank closure member has a second stop member. The second tank closure member is flexibly mounted in an axial direction relative to the first tank closure member, the second tank closure member. The second stop member, in a closed position of the tank closure, forms a mechanical stop relative to the first stop member to prevent axial movement of the second tank closure member relative to the first tank closure member against the spring force of the bias member.