I did this job for someone a few days ago. Sometimes you never know what you'll find. When I finally hacksawed the bolts off, I found the back of the tank was cracked. Not only that, but when the last repair was done 10 years ago, whoever did it knew the tank was cracked, and ran cement and epoxy along the outside of the tank along the crack. That repair lasted for 10 years, but it's not a smart repair. Suppose the homeowner went on vacation, and the crack started leaking then. They could have come home to a floor that was soaked and weakened.

Moral - when you do a repair, do it right, don't cut corners.