An elongated elastomeric gasket (10) seals a pair of opposing flanges (12, 14) against the passage of liquid without compressing the flanges (12, 14) together. A reinforcing spring (32) is embedded within the elastomeric gasket (10) and is shaped so as to react when deflected by the operation of installing the gasket (10) into an operative position between the flanges (12, 14). A strategically located U-shaped bend (34) formed in the reinforcing spring (32) causes, in a preferred embodiment, contact pressure to be increased between opposed sealing beads at the other end of the gasket. More specifically, lateral contact pressure between a first pair of sealing beads (24) and their associated contact faces (38) is increased as a direct result of the reinforcing spring (32) being displaced during the assembly process. Likewise, lateral contact pressure between a second pair of beads (28) and their respective contact faces (42) is increased in direct response to the lateral displacement of the reinforcing spring (32) in the region of the first beads (24) during assembly.