If it was a very old one, it may have been glued by the previous owner. The clamps from 2006 and early 2007 were a more brittle plastic and the tabs would break and people would glue them even though we replaced them for free. Is it a DC pump? The AC models from Germany if 230V/50Hz will not work here even with a voltage adapter, they depend on the Hz for the speed and the coil for 50Hz cannot work on 60Hz and vice versa.