If you know who your great-grandpa was, look up his death certificate and that should tell you his parents.  If not, try checking a census record at a time when he would have been a child, if you know where he lived.  That would give you his parents and siblings.  If you just say you're related to particular Maxwell, and all your're doing is sitting back waiting for someone else who's related to respond, you may be waiting a long time.  Or forever.  Take the names you know, and everything about them, and work backward.  You're bound to find something.