Abstract: A method of installing a seal on a fuel injector includes installing a seal in a groove in an outer surface of the fuel injector. The seal is then clamped in a heated clamp portion at a temperature sufficient to soften a material of the seal to allow the material to flow into the seal groove. The seal is then cooled while being maintained in the clamped state to allow the heated material to set to a desired outer diameter size. The seal groove in the fuel injector may be provided with an extrusion zone into which the softened material of the seal is allowed to flow as the seal outer diameter is reduced to the desired diameter during the heating and clamping process.