Abstract: The flexible ball joint is provided with a bellows which is protectively mounted inside a shell. A portion of the shell serves as the spherical socket and a portion of a sphere serves as the ball for the ball joint. The ball is mounted in the socket and is concentric therewith. One end of the bellows is attached to the shell and the other end is attached to the ball. A plurality of generally equally angularly-spaced Purbon buttons are mounted on a support ring which is mounted on the surface of the socket. These buttons are in engagement with the surface of the ball so the ball joint can pivot freely over a wide range of temperatures. A generally spherical shell-like member is mounted in fixed and closely-spaced concentric relation to the outer surface of the spherical socket to limit axial movement between the socket and the ball and hold the Purbond button on the support ring. In addition, the shell-like member has formations shaped to define cooling channels for the protective bellows.