How to Replace Toilet Anchor Bolts

Toilet anchor bolts, also called closet bolts or flange bolts, secure the base of the toilet to the floor. Most of the time, the original bolts remain in place, even during wax ring changes. If an anchor bolt or the closet flange beneath the toilet breaks, however, replacing the bolts is necessary. Once the old bolts are out -- inserting new ones is a breeze. Getting the old ones out, though, can be tough.

The closet flange resembles a short pipe with a flat, round collar. The collar sits on the finished floor and the pipe extends downward to connect with the drainpipe. The collar has two long slots to hold the anchor bolts. When setting a toilet flange, the plumber will align the slots on the sides, to match up with the holes in the toilet base.

Anchor bolts fit loosely, heads down, in the flange. Only when the toilet is in place and you tighten the nuts on the bolts, will the force tighten the bolts in the flange.

The best toilet bolts are brass, which helps them resist corrosion. Cheap toilet bolts made from other metal, and the metal nuts that fit on the bolts can rust. Before trying to remove existing nuts, spray them with a lubricant. With a pair of pliers, grab the tip of the bolt above the nut, and with an adjustable wrench, grip the nut firmly and twist counterclockwise.

If that loosens the nut, you can usually twist it off with the adjustable wrench. If the toilet flange beneath is broken, though, once the nut reaches the top of the bolt and you can no longer grip it with the pliers, bolt and nut are likely to spin. When that happens, cut the bolt off with a small saw fitted with a metal blade. If the original installer cross-threaded the nut and stripped the bolt threads, you might also have to cut the bolt.

Spray lubricant is also beneficial for loosening the nuts on tank bolts. Hold a tank bolt in place in the tank with a screwdriver, while twisting the nut off with a wrench.

After shutting off the toilet's water supply line, flush and hold the handle down until all the water drains from the tank, and then disconnect the supply line at the valve. You can use a plunger to push residual water out of the bowl or bail it out. It helps to have two people to lift the toilet straight up and off the bolts. After putting on disposable gloves and scraping away the old wax ring with a putty knife, slip the old anchor bolts out of the flange slots.

Insert new bolts in the flange slots, heads down, and align them opposite each other to match the corresponding holes in the toilet base. With the new bolts in place, fit a new wax ring on the flange and set the toilet carefully over the bolts, pressing gently until it rests flat on the floor.

In the replacement bolt kit, you'll find flat stoppers, washers and nuts. The stopper slips on first, then the washer and finally the nut. Tighten the nut down with an adjustable wrench only until it's snug. Do not overtighten. Cut the top of the bolts off about ¼ inch above the nuts and snap the decorative bolt covers in place.