Fixing that Dripping Tap
A dripping tap or leaking tap usually means that the tap washer needs renewing, but it can also be caused by a damaged valve seating. If the drip is from a mixer nozzle, then change both tap washers.
Removing the headgear
1 Turn off the water supply to the taps *. Make sure the tap is turned fully on, and put the plug into the plughole to stop any small parts falling down the waste pipe. This is an important tip and can save you a lot of time and aggravation later on.
*Turn off the water under the taps at the service valves or at the mains.
2 Unscrew or lever off the cover of a non-rising spindle tap to expose the retaining screw (use a flat head screwdriver). Remove the screw and put it in a safe place. Remove the head of the tap.
Alternatively with a rising spindle tap, prise off the index disc (in the centre of the handle) (again with a screwdriver) and remove the retaining screw to release the capstan (handle). Use an Adjustable spanner wrapped in some rag or cloth to unscrew the metal shroud and lift it from the headgear nut.
3 Undo the larger headgear nut with a spanner. Do not force the nut. If it is stiff, brace the tap body by hand or with a pipe wrench wrapped in a cloth, to prevent the tap from turning and fracturing or damaging the pipework attached to it. If you damage the pipe at this point it could cause a leak and you would need to call a plumber.
4 If the nut is still difficult to turn, apply penetrating oil round the joint, wait for about 10 minutes to give it time to soak in, then try again. You may have to make several applications. It is also possible to apply heat to it with and electric paint stripper or blow torch but be very careful.
Replacing the Washer
5 Prise off the washer with a screwdriver. If there is a small nut holding it in place, unscrew it with a spanner (normally 8mm). If it is difficult to undo, put penetrating oil round it and try again when is has soaked in. Then prise off the washer.
Alternatively if the nut proves to difficult to remove, then you can replace both the jumper valve and washer in one unit.
6 After fitting a new washer or washer and jumper valve, grease the threads on the base of the tap before reassembling. It is possible to get a special silicone gel from the plumbers merchants, but something like vaseline would do.
Repairing the valve seating
When renewing a washer, have a look at the valve seat inside the tap body. If it is rough or scored, possibly by grit, the seal between the washer and seat will not be effective even with a new washer and will let water by.
The easiest repair is with a combine washer and seating set, available at hardware stores.This has a plastic seat part, which fits into the valve seat, and a washer and jumper valve unit will fit into the headgear.
When the tap is turned off, the plastic seating is forced firmly into position. It may take a few days of using the tap for the new seating to give a completely watertight seal.
An alternative repair to the valve seat is to buy or hire a tap reseating tool and grind the seat smooth yourself.