How to repair a dripping tap
Tools
One large open-ended spanner
Old screwdriver (for prying)
Possibly also:
One small spanner
One or two pipe wrenches
Cloth for padding jaws
Screwdrivers
Materials
Replacement washer or a washer-and-jumper valve unit OR a washer-and-seating set, petroleum jelly.
Possibly also: penetrating oil.
Removing the headgear
1. Turn off the water supply valve. Make sure the tap is turned fully on and no water is coming out, and put the plug into the plug hole to stop any small parts falling down the waste pipe.
2. Unscrew or lever off the cover of a non-rising spindle tap to expose the retaining screw. Remove the screw and put it in a safe place. Remove the head.
Or, alternatively: with a rising spindle tap, pry off the index disc and remove the retaining screw to release the capstan from the spindle. Use a wrench wrapped in cloth to unscrew the metal shroud and lift it away from the headgear nut.
3. Undo the 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 the pipe work attached to it.
4. If the nut is still difficult to turn, apply penetrating oil round the joint, wait about ten minutes to give it time to soak in, and then try again. You might have to make several applications.
Fitting the washer
1. Pry 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 around it and try again when it has soaked in. Then pry off the washer.
Or, alternatively: If the nut is impossible to remove, you can replace both the jumper valve and washer in one unit.
2. After fitting a new washer or washer and jumper, grease the threads on the base of the tap before reassembling.
Repairing the valve seating
When renewing a washer, inspect the valve seat inside the tap body. If it is scaled or scored by grit, the seal between washer and seat will not be effective, even with a new washer.
The simplest repair is with a washer-and-seating set. This has a stainless steel seat to fit into the valve seat, and a washer-and-jumper valve unit to fit into the headgear. When the tap is turned off, the stainless steel seating is screwed firmly into place. It may take a few days for the new seating to give a completely watertight fit. An alternative repair is to buy or hire a tap re-seating tool and grind the seat smooth yourself.
Tap conversion kit
You may be able to get a tap conversion kit to change the style of taps and replace worn or broken mechanisms. Newer heads can be changed for older style ones, or vice versa, or a tap with a crutch or capstan handle can be given a newer look. The spout and body of the tap remain in place. Some kits have bushes to fit different tap sizes. The kits are available from most DIY stores and fitting instructions are included.