I have a 1999 Ultra Classic. I have a rider back rest. It's the type with the two legs that has a spring in between to hold tension on the mounting bracket and slides between the seat. It has gotten real shaky up inside. Has anyone had one of these apart and are they repairable? Just wondering how they are put together inside before I start taking the covering off. Can't find anything on them in the parts manuals. Any help would be appreciated. Thanks