Repairing leaking or sticking taps:
Shut off the water as per instructions Turning off the water supply: at the start of this book. Remove indicator dial. It will either flick out with a craft knife or screw out with a spanner.
Now remove the cross top or dome and remove any body cover to expose the head works. Now with a spanner on the base hex nut of the tap head works turn anticlockwise to undo it. Lift up to expose the spindle and the tap washer itself. Check for wear and tear. Place your fingernail inside the tap and run your nail around the seat to see if your nail drops into any crack that has worn its way into the seat making a tracking channel for the water under the tap washer. If you do strike a crack you will have to use a reseating tool to grind the crack out. Simply insert the reseater tool and wind the top assembly down onto the brass seat and holding this section still wind the very top of the reseater to begin grinding away at the crack to completely remove it. Remove the reseater and after flushing with water you will be able to see the progress.
Also you may be able to fit a dome-like tap washer which is designed to sit down inside the hole created by the seat and bypass the crack in the seat with a better chance of success if you want to try this way of doing it before going to the expense of buying a reseater tool.
Note: These dome-like washers have a really soft turn off. So only turn the tap till it stops leaking.
While you have the head works out wind the stem out of the head and lubricate the thread to ease any future sticking. If this does not stop the tap from sticking it means the shaft is damaged beyond repair and the tap needs a new head works. But before you go buying a new head works set check out the cost of buying a whole new tap, as the head-works can be expensive alone.