Mine filled up half way as well. It's a common problem.
I've heard that if you caulk it, it might last a year...the forces ripping it apart will do it again (it's pretty obvious why if you look at the position of those clips holding it to the top frame)-:
I used a q-tip to apply gorilla glue to it after cleaning it w/ no luck.

What does the repair DVD say to do to get the large reservoir in? Anything simpler than ripping out the entire e-box?