A lot more information would be required for suggestions to be offered as we have no idea which RV brand, model #, construction, age, as well as where in the rear is it leaking, just to mention a few. How about some pictures of the area that's "coming apart"?
There's lots of good folks here with tons on info and very willing to help you, you just need to provide enough info about your problem so they can understand what your facing to ensure the info they provide really does HELP you, not cause more problems.
Days camping (2016)----181 days
Days camping (2017) --- 82 days
2016 Wildcat MAXX 28RKX (33' TT), 2007 13' Scamp
2015 Ram Laramie Hemi, w/air suspension
30 years RV'ing
11 different RV's