The fact that someone was in there already says a lot!
You have a chronic/intermittent problem. Until someone gets in there and finds the real underlying problem, you'll be fixing it every year/month/excursion.
Take the time. Bite the bullet. Grasp the nettle firmly. Do it Right.
Take down a whole section of coroplast and get in there with good lighting. See what's right and what's weak/wrong up in there. Then fix it so it stays fixed!
TT 2015 19RD "TheJayco"
TV 2003 F-350 "Montblanc" - Housebroken chore truck
Sitting in The Cheap Seats.
And proud of it!