Repairing Toilets

Because it gets used so often, your toilet has a good chance of eventually needing repair. Although some people find the prospect of working on a toilet distasteful, as long as you flush it once or twice before beginning, you will be dealing with clean water only. You may find some rust and sediment in the tank. The inner parts of a toilet are fairly simple. When someone flips the flush handle, a chain reaction of events starts. The handle lifts the trip lever, which in turn pulls a chain that lifts the tank flapper off the flush valve. (In older units, a lift rod raises a tank ball.) As water rushes down through the opening into the bowl, the reservoir of water and the waste in the bowl yield to gravity and pass through the toilet’s trap, down through the closet bend, and out a drain line.

Inside the tank, the float (or in older systems the float ball) descends along with the outrushing water until, at a predetermined level, the shutoff rod is attached to trips the ballcock, which is a water supply valve. At the same time, the tank flapper settles back into the flush valve, stopping water from leaving the tank. The ballcock opens to shoot a new supply of water into the tank through a refill tube and into the bowl through the overflow tube. When the float rises to its filled position, the ballcock shuts the water off. A wax ring seals the toilet bowl to a flange on the closet bend and keeps water from leaking out onto the floor. A spud gasket seals the tank to the bowl.

Toilet Repair Chart





Water continuously trickles or runs into tank and/or bowl (tank run-on).

Water level is too high.

Flapper or tank ball isn’t sealing properly.

Ballcock is faulty.

Adjust trip lever chain, adjust water level in tank, or replace leaky float (see below). Clean the flush valve under the flapper, or replace worn flapper.

Repair or replace ballcock.

Bowl overflows when flushed.

Toilet flushes incompletely.

Trap or drain is partially clogged.

Trap or bowl is clogged.

Run a toilet auger through the toilet, or clear drain.

Tank leaks.

Water is spraying up against the lid.

Gasket between tank and bowl is faulty.

Tank is cracked.

Anchor the refill tube so it sprays into the overflow tube.

Replace the spud gasket.

Replace the tank.

Bowl leaks.

Leak appears as a wet spot on the floor.

Wax ring is not sealing.

Bowl is cracked.

Pull up the toilet and replace the wax ring.

Replace the bowl.

Tank “sweats”—drops of water appear on the outside.

Condensation occurs due to difference in temperature between air and tank water.

Buy an insulation kit and install in the inside of the tank.

Fixing Tank Run-On

Most of a toilet’s mechanical action goes on inside the flush tank, and that’s where most common toilet problems develop. If water continually trickles or flows into the tank and/or bowl, start with the simplest diagnosis: The float may be rising too high, causing water to trickle down the overflow tube. If fixing that doesn’t solve the problem, see if the chain is tangled or has fallen off. Check flapper and ballcock.

Adjust the float ball. Remove the tank lid, and look to see if the water level is too high— it should not be above the overflow tube. If it is, the water will shut off when you pull up on the float ball. Bend the rod slightly downward so the float ball sits a bit lower.

Check the float for damage. A cracked float takes on water. When this happens, the ball won’t rise enough to trip the ballcock. To check out this possibility, agitate the ball. A faulty ball will make a swishing sound. Unscrew a faulty float ball, and replace it with a new one.

Fix a leaky flush valve seat. If water continually trickles into the bowl, and perhaps even causes the toilet to weakly flush occasionally, the problem is probably in the flush valve. It has two parts: a flapper or a tank ball, and the flush valve seat into which the flapper or ball drops to seal the bottom of the tank while it fills. Often the seat simply needs cleaning.

NOTE: Shut off the water to the tank, and flush the toilet to get the water out. Check the tank ball or flapper. If it has gunk on it, wipe it clean and smooth it using an abrasive pad. Once it’s cleaned, feel the valve seat to see if it is pitted or corroded if it’s metal. Flexible seats can be pried out and replaced. If you have a damaged metal seat, replace the entire flush valve.

Repair a diaphragm ballcock. NOTE: Shut off the water and flush the toilet. Remove the four screws on top of the ballcock, and lift off the bonnet. Clean out any deposits. Replace any worn parts, including the plunger. If a number of parts look worn, replace the entire ballcock.

Repair a plunger ballcock. NOTE: Shut off the water and flush the toilet. This is the oldest type of ballcock, and there are a number of parts that can go bad. You may need to replace it with either a diaphragm or float-cup ballcock. But first try cleaning and replacing the washers. Remove the thumbscrews holding the float rod mechanism in place, then lift it out and set it aside. Remove the plunger by pulling up on it. Typically you’ll find a seat washer as well as a couple of other washers. (In very old models, you may even find leather washers.) Remove and replace all of the washers, reassemble the mechanism, and turn the water back on.

Repair a float-cup ballcock. NOTE: Shut off the water and flush the toilet. This is the newest and the simplest design, and it rarely acts up. Pry off the cap, then remove the bonnet by lifting the shutoff lever on the float rod mechanism, pushing the mechanism down, and twisting counterclockwise firmly. Clean out any gunk, and replace the seal if it looks worn.

Fixing Leaky Tanks and Bowls

Puddling of water on the floor near the toilet can be fixed in several ways. On a hot, humid day, condensation dripping from the cool outside of the tank or bowl could be substantial enough to make a puddle. You can simply live with it or install rigid-foam tank insulation. A chronic leak probably means a faulty water supply connection, spud gasket, or wax ring. Often you simply need to tighten the hold-down bolts to solve the problem. A crack in a tank can sometimes be patched from the inside with silicone sealant. A cracked bowl should be replaced.

A leak at the water supply line - If the leak comes from where the water supply enters the tank, first tighten the locknut. If that doesn’t work, shut off the water, flush the toilet, and sponge out the water that remains in the tank. Disconnect the water supply line, remove the locknut, and replace the old beveled gasket and rubber washer with new ones.

A leak between the tank and bowl - Extended use can cause the tank hold-down bolts to loosen enough to produce a leak at the spud gasket. Use a screwdriver and a wrench to tighten the bolts to squeeze the tank against the spud gasket. If the leak persists, shut off the water, flush, and sponge out any water. Detach the supply line, remove the hold-down bolts, lift out the tank, and replace the spud gasket. Reassemble.

Older-style connections - With some old toilets, the tank connects to the bowl with a fitting. If leaks develop at either end of the fitting, tightening the nuts may stop the leak. If not, take the toilet apart and replace any worn parts from a plumbing supply source.

A leak at the base of the bowl - If the bowl is cracked, you’ll have to replace it. If the bowl is sound, try gently tightening the hold-down nuts. If that doesn’t stop the leak, replace the wax ring. Begin by shutting off the water, flushing the toilet, and sponging out any remaining water. Disconnect the water supply line, and remove the nuts on the hold-down bolts. Lift out the toilet. Scrape away the old wax ring and any old putty on the bottom of the bowl. Press a new wax ring in place according to the manufacturer’s directions. Reinstall the toilet.

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