sometime in my CJ's history a fiberglass tub,fenders,hood,and windshield frame was bought. Whoever changed this started with a very junky frame,so over time the body started to crack in places.
they also did not use washers on some bolts so I have small cracks around those.
I have recently taken the body off,repaired and made it stronger.I also replaced the frame.
here is my short fiberglass list
Make sure the frame is in good shape.
Use bigger washers on all bolts.
Any holes that are cut into the fiberglass,seal them so water cannot get between the 'glass.
consider putting a rollcage in it that attaches to the frame and side protection.
all wires that were grounded to the body/dash will have to be rewired.
fiberglass is very bad for your lungs! so use the correct face protection when cutting into it.
It is also very itchy.