Even something as durable as a toilet can break or crack. If your toilet stops flushing or springs a leak, you may feel it necessary to call a plumber. If your toilet tank or seat lid cracks, however, you may find it more convenient to fix and replace on your own. You can accomplish either job without any knowledge of plumbing or without having previous repair experience.
Make padding out of a couple of towels, and place the padding on the floor, counter or table.
Place the broken pieces of the toilet tank lid on top of the padding to prevent further damage to the pieces as you work with them.
Arrange the pieces so that they are all upside down on the padded surface. This means you'll be looking at the inside of the tank lid rather than the part you'd see from the outside.
Glue the cracked pieces of your toilet lid back together with a strong adhesive. Be gentle with the pieces to prevent additional cracking. Put the glue on the inside surface of the break, and hold the broken pieces together until they bond.
Let the freshly glued toilet lid sit in an area where it won't be disturbed. Do not attempt to move it until the glue has dried completely.
Replace the toilet lid, being careful to avoid hitting it against the tank or wall.
Position the toilet seat so that the lid is down over the seat, covering the toilet bowl.
Flip up the tabs covering the bolts that secure the seat and lid to the toilet.
Use a wrench to undo the nuts beneath the bolts you uncovered. The nuts will be on the underside of the toilet.
Remove the toilet seat and lid by lifting it up and away from the rest of the toilet.
Install a new seat/lid assembly the same size as the one you removed. Put the seat/lid in place, and tighten the nuts by hand. Use a wrench to turn the nuts just a little, and tighten them securely.
Keep a firm hold on your wrench as you repair your toilet. If it slips and hits the toilet, it could damage or crack it. Purchase a replacement toilet lid as soon as possible. Gluing a toilet lid is only a temporary fix.