Basic Plumbing Maintenance
Household Plumbing Made Easy
Change a Tap Washer
Replacing a tap washer is one of those chores that needs to be done periodically. Luckily, it’s easy once you know how.
The first step in replacing a cold water tap is to turn off the water supply to your home. You’ll usually find the valve near your gate. In the case of a flat, ask your caretaker. If you are changing a hot water tap washer and you have an equal-pressure system, when you turn off the mains water open the hot water tap and the flow will soon cease.
- Remove the handle. In some cases, the screw is fitted on the side, and in others, it’s on the top.
- Now remove the dome or plastic insert. To avoid damaging the chrome if the dome is tight, protect it with a cloth when using your adjustable wrench or water pump pliers.
- Un-screw the brass valve assembly.
- Remove the nut holding the washer in place, replace the washer and re-tighten the nut.
- Reassemble the tap in reverse order to disassembly, make sure that it is closed, turn the water mains back on and test your repair. Bear in mind that the water flow will cease sooner than before the repair as the washer has not yet been compressed so, tighten the tap only enough to close it. If you crank it down as far as before, you will be replacing the washer sooner than you think.
- Turn off the water supply to the cistern – the stopcock is usually mounted on the wall or inlet pipe to one side of the unit.
- Remove the cap (if there is one).
- Close the ends of the split pin that acts as a pivot for the float arm and remove it.
- Manoeuvre the arm free, using it to pull the piston towards the end of the cylinder as you do so.
- Remove the piston. A hint: you have to be careful not to damage it. If you cannot grip it with a pair of pliers, push it back in, put the lid back on the cistern and then turn the tap on for a second or two. The jet of water is often enough to push the piston out far enough for you to get a good grip on it.
- While the piston is out, use a little bit of fine sandpaper on a length of dowel to remove any deposits in the cylinder and, if the piston itself is brass, then also clean it, should it be necessary. You can also drape some cloth over the end of the cylinder and turn the water back on for a few seconds, not strongly, but enough to push any dirt out. The cloth will stop the water from blasting out.
- Pry the washer out of its recess in the head of the piston and insert the replacement.
- Position the washer with the slot for the float arm directly downwards and insert it into the cylinder.
- Gently manoeuvre the float arm into position. You will be able to do this only if the slot in the piston is positioned correctly. Hint: you will find it easier to position the float arm properly if you flush the toilet beforehand – if it’s still full of water, the float will tend to make things difficult.
- Re-insert the split pin and spread the ends slightly with a screwdriver blade to prevent it from falling out.
- Turn the water back on and raise the float arm, checking that the water coming into the cistern stops flowing.
- Incidentally, if you find that the water in the cistern does not come up to the same level as before, it’s because the new washer is a little thicker than the old one where it meets the nozzle. If necessary, bend the float arm up a little, so that the float can rise higher and fill the cistern to the required level. Later on, you may need to bend the arm down again as the washer is indented where it meets the nozzle.
- Fine sandpaper