Regrinding or Renewing the Seat.If a tap continues to drip after you have replaced the washer, the seat is probably worn, allowing water to leak past the washer. A simple way to cure this is to cover the old seat with a nylon liner that is sold with a matching jumper and washer. A Catford Plumber will carry out this task.1). Drop the liner over the old seat, replace the jumper and assemble the tap. Close the tap to force the liner into position. Alternatively, use a tap-grinding tool to put a new smooth surface on the seat. The tool uses serrated cutters to grind out any imperfections that might be allowing water past the washer. With the headgear removed, insert the grinder and screw the threaded bush to the tap to locate the tool securely. Push down and twist the grinder clockwise. Resurfacing is complete when the whole seat is shiny and new looking.Replacing O-rings.On a mixer tap each valve is usually fitted with a washer, as with conventional taps, but in most mixers the gland packing has been replaced with a rubber O-ring. The base of the mixers swivel spout is also sealed with a washer or O-ring. If water leaks from that, it needs replacing. Firstly, remove the mixer spout, and the retaining screw may be accessible from the front, if it is at the back, you may have to use a cranked screwdriver to remove it. Catford Plumbers are skilled tradesmen. Lift out the swivelling spout, then, use a small screwdriver to flip out the O-ring from its groove. Take care not to scratch the metal. Make sure you always lubricate a new ring with silicon grease, then, carefully slide it into place before refitting the spout and replacing the retaining screw
