hey guys, while rebuilding my engine. i took the fuel injectors out of the intake and off the fuel rails. so i need to replace the o rings. i bought the o ring kits from napa, but the kits come with 2 o-rings, a hard plastic seal of some sort, and a little blue nipple of some sort. i'm assuming the later two are meant for the inside of the injector? anyone have a clue how to disassemble the injectors to put these in? or should i not worry abt it and only replace the two o rings?