Modern toilet lids connect to the bowl using plastic bolts that are placed through pre-drilled holes on the bowl, secured with plastic nuts. Plastic bolts are now used in place of metal hardware because they are not prone to rust and corrosion. If the bolt on your toilet lid breaks, or you would simply like to replace the seat, you can easily remove the lid from the base. If the bolt is stuck, it can be removed using a hacksaw.
Locate the two plastic bolts securing the lid to the bowl. The bolts are located on the underside of the bowl, just behind the rear of the bowl opening.
Remove the two plastic nuts using an adjustable wrench (or pliers) in a counterclockwise direction.
Lift the lid assembly straight up and off of the toilet bowl.
If the plastic nuts can not be removed or are broken, cut the bolts either above or below the bowl using a hacksaw.