I have removed every screw ( I think! ) from the bottom of ths vac (mine is M# v13102 - date code= 2805 - looks similar to this V1310 listed here) & I could get the top to loosen enough to remove the broken belt, but can't get the thing to open up to replace the belt. Semms to be holding fast on the front where thr rubber bumper is, & the cover on the bottom looks like one stationary piece. How do I get this thing open to replace belt? Please HELP!