Is it an OEM or a jobber one?
I had no luck with jobber tailgates.
My wife's father (who sold me Big Brother) lost the original tailgate on the road...
After, Big Brother had two jobber tailgates which ended to split, as yours. I tried glue, and then rivets. Even the rivets have cut and needed to be replaced.
I bought a really good shaped OEM used tailgate in a salvage yard, and replaced the second jobber one. Since then (more than 10 years ago), I have no trouble with the tailgate.
Jeff / 1984 F350 Crew Cab 4x4/5.8L w351 4V/ T18/ D50 4.10 front/ 8' bed.
Restored 2019-2022.
Nicknamed «Big Brother 1984», due to its soooo-looong shape & nod to George Orwell's 1984 famous novel.