A coil spring for use in a cavity, such as in a groove of a pin, a housing, or both. The cavity can also be part of a seal assembly. The coil spring can have a longitudinal component positioned within the plurality of interconnected coils that runs along the spring coil axis in order to increase rigidity of the coil spring. The longitudinal component applies a load against the coil spring and/or provides restriction against the coil spring taking a shape or size different than that of the coil spring retaining groove.