Repairing A Toilet

Toilet Construction:

Toilets are simple devices and they are all work in a very similar manner.  They are based on two items, a bowl and a tank although some manufacturers have models where they have molded these two items as one piece.

The bowl sits on the floor and has a rubber or wax gasket sealing the drainpipe to the base of the toilet.  These gaskets should never be reused.  They are very inexpensive and anytime the bowl is lifted from the floor, the gasket should be replaced.  I prefer the wax gasket as I feel it molds better to any imperfections in the porcelain material on the base of the bowl and the drainpipe flange. 

The toilet bowl gasket not only prevents water from the bowl from seeping onto the floor when the toilet is flushed, but it prevents sewer gas from entering the home.

Selection of toilet bowl gaskets

The bowl is held down tight to the drainpipe with two bolts.  The bolts, which should be brass, are designed with heads that fit through slots in the toilet drainpipe flange.  These bolts stand straight up and fit into the holes in the base of the toilet.  When tightened they compress the gasket between the base of the bowl and the flange and subsequently hold the toilet tight to the floor. 

In a few instances, there may be an additional two holes in the toilet bowl base.  These holes allow for the placement of two additional fasteners through the base of toilet and into the floor.

The tank contains two basic parts, although some manufacturers have designed one mechanism that contains both functions of the two parts: 

1. Float or fill valve (Figure 3).  The float or fill valve allows water to enter the tank to a certain predefined height. 

Selection of toilet float or fill valves

2. Flapper valve (Figure 4).  The flapper valve allows the water stored in the tank to be delivered to the bowl.

Selection of toilet flapper valves

A gasket and usually two and in a few instances three brass bolts, washers and nuts (Figure 5) hold the tank to the bowl and compress the gasket to prevent water leakage.

Selection of toilet tank gaskets

The incoming water pipe, which should have an independent valve, connects directly to the base of the float or fill valve.

1. Use a sponge remove any water left in the bowl,

2. Remove the nut that holds the water intake pipe from the bottom of the toilet tank.  This nut is holding the incoming water pipe to the float/fill valve.

3. Remove the nut that holds the float/fill valve tight to the bowl (located just above the water intake nut and it is on the outside of the bowl),

4. Remove the old float/fill valve assembly and install a new unit. 

5. Tighten the nut that fits over the thread on the bottom of the float/fill valve (this nut compresses a gasket on the inside of the tank between the bottom of the tank and the float valve),

6. Put the water intake pipe back in position and tighten the nut that holds it to the bottom of the float valve. 

7. Turn the water to the toilet on and look for leaks.

To replace the float/fill valve:

If the flapper valve needs replacement, you may have to remove the tank from the bowl.  This is dependent on the manufacturer of the toilet and style of valve used.  Some flapper valves can be replaced without removing the tank.  If you know the manufacturer of the toilet, you can easily buy the correct replacement.  If you don’t know the manufacturer, take a close look at the flapper valve and then buy a suitable replacement.  Follow the installation instructions with the replacement.  If the tank has to be removed, I recommend replacing the bolts, washers, and the gasket (Figure 5) that sits between the tank and bowl.  In many cases once these gaskets are compressed they will not reseal properly, once removed.

Symptom:  Water on floor. 

To replace the gasket:

1. Flush the toilet,

2. Remove the nut that holds the incoming water pipe to the bottom of the flush valve.

3. Remove the nuts on the bolts that hold the bowl to the floor (you may have to remove the bolt covers, use a screwdriver on the edge and pry upwards, the caps should pop off). 

4. Once the nuts are removed, lift the toilet straight up and off of the protruding bolts.  The toilet may feel like it is glued down; it is the old gasket that is holding it in place, wiggle the toilet, and it will come free.  All toilets have the drain trap molded into the bowl; this means that there is water still in the bowl, so expect water on your floor! 

5. With the toilet is removed, the gasket will be fixed to the drain flange and/or to the base of the toilet bowl.  Remove all of the old gasket material using a scraper. 

6. Place a new gasket over the molded drainpipe that protrudes from the base of the toilet. 

7. Lift the toilet over the bolts (I recommend replacing the bolts) and lower down so the bolts are protruding through the holes in the toilet base. 

8. Using the nuts, washers and if applicable the bases for the bolt caps; tighten the nuts to compress the gasket to the drainpipe flange.  It is best to hand tighten the nuts by going back and forth between the two bolts rather than tightening one all the way down and then the other (this will provide better seating of the gasket). 

9. Replace the caps (it may be necessary to cut the tops of the protruding bolts, using a hacksaw, in order to get the caps to fit.  Always cut the bolts above the nuts). 

10. Reconnect the water supply line.

CAUTION:  All toilets are molded from porcelain, which is a very brittle material.  Tightening any bolts with to much force may cause the porcelain to crack!

Additional information on toilets

Additional information on replacing a toilet