Abstract: A cap for a fuel tank has a cap body for screwing into the filler neck of the fuel tank with an "O" ring interposed therebetween, and a lid member for mating to the cap body, both the lid member and the cap body having coacting structure for mutual interengagement to maintain the lid member normally mated to the cap body but separable in break-away relationship from the cap body to leave the cap body intact within the filler neck upon application of external force, such as through collision, to the lid member. The coacting structure may take the form of engaging recesses, holes or grooves on one member and of engaging projections, tabs or pins on the other member.

Abstract: A fuel tank cap comprising a cover, a bracket, an annular sealing member disposed around a cylindrical portion of said bracket, an annular retainer sandwiched between said cover and said annular sealing member, and an annular gasket sandwiched between said bracket and said retainer, the outer surface of said annular retainer being substantially coextensive in shape with the outer surface of said gasket, and one of the peripheral edge portions of said gasket having a projection held in locking engagement with said annular retainer.