This will get rid of that for you. We have them in every bronco at the shop right now because of that reason.
This link will get you 10% off if you choose to order...
Bronco Body Brace
The body brace is a bolt-in body stiffener that stiffens the side walls of the bronco body.
Made from 3/16 steel
Bolts into factory mounting holes!!
Installation is super easy!! Approx. 30 mins
The only tool required is a T50 torx!
Made for hard tops may fit some...