A fuel injector for effectively preventing excessive loading of a component mounted internal to the injector is provided which includes a one-piece retainer having first and second connector portions for permitting two independent loads to be applied to different internal components of the injector. The second connector portion includes threads for engaging a nozzle assembly to impart a compressive force on the nozzle assembly. The first connector portion also includes threads for engaging an outer barrel for placing a first compressive load on a load sensitive internal component, such as a center tube of an injection control valve. In this manner, the second compressive force can be set at a minimum level independent from the first compressive force to permit the size of the center tube to be minimized thereby reducing the overall size of the injector. Also, a locking device including a locking ring for engaging the outer barrel ensures a secure connection between the second connector portion and the outer barrel to prevent shifting at the connection during operation of the injector as the load at the connection transitions from a tension load to a compression load thereby ensuring only a minimum load on the center tube. A novel sealing assembly is also provided to permit effective sealing between the end of the center tube and the outer barrel regardless of tolerance variations while providing simplified valve stroke setting capability.