Why is my straight edge getting distorted when I bevel it? I have a straight edge that I want to bevel...



When I apply the bevel it crimps and gets distorted...



How can I get a straight smooth bevel all the way down?  Here is my blend file...

blend file

Thanks for any help.
It looks like not all the adjacent faces are connected. The big face on top of the side panels are the problem (image 1). You just need to connect them to the rest. To do that, just create an edge loop on it and merge (Alt+M) the bottom vertex with the one on the top of the wheel hole (image 2). That should do it (image 3).