Ensure you have the right size threaded piece and cutter for the reseater.
Step 2 – Insert cutter
Place the reseater blade downwards into the tap body.
Step 3 – Secure in tap
Tighten the threaded section in the retaining nut screw hole.
Step 4 – Attach tap reseater driver
Attach the tap reseater driver adapter to an appropriate power drill using the same method for attaching a regular drill bit.
Step 5 – Position drill
Slot the drill adapter onto the tap reseater.
Step 6 – Low speed
Use the drill on a low setting to grind down the seat. Only a light pressure and quick bursts of drilling should be needed.
Step 7 – Inspect seating
Remove the tap reseater and inspect the seat. The process may need repeating several times (with slightly more pressure for tougher build-ups), until you have a shiny-looking seat which is smooth to the touch.
Reassemble the tap
Whilst the tap is disassembled, it is advisable to also check that the O-rings and washer are in full working order and replace if necessary.
Then you can reassemble the tap in the reverse order you took it apart. The tap should now be fixed, if the leak persists, contact a plumber.