I'm attempting to install a new cable for my rear v-brake. Despite having a clean cable cut, I have been unable to thread the cable end thru the final piece of housing + the curved metal tube + metal end piece, (the part which actually attaches to the brake and works as a quick release). The cable is getting stuck where the housing and the curved metal tubing are attached. I'm assuming I don't separate the housing from the metal tube, right? In any event, they don't want to easily separate. Any suggestions?