Fix hairline cracks in a broken cistern by filling the cracks with a porcelain sealer. Repair a cistern that overflows by adjusting the inlet valve correctly. Replace the siphon to fix a cistern that does not flush easily.Continue Reading
Start by pinpointing the area of the cistern that needs to be repaired. Cistern problems arise from cracks on its surface, blockages in the drainage system or incorrect connections with the pipes.
Start by draining the cistern completely. Allow it to dry naturally. Apply a porcelain sealer directly on the crack on the cistern's surface. Ensure that the cistern is not in use for a couple of days after repairing it.
Adjust the inlet valve to fix a cistern that overflows. To raise the water level in a cistern fitted with a Torbeck valve, turn the float clockwise. To lower the level, turn it counter clockwise. Raise the water level in a cistern fitted with a traditional metal float arm by bending the arm downwards. Bend the arm upwards to raise the level.
Fix a cistern that is difficult to flush by changing the siphon. Start by disconnecting the water supply to the cistern. Drain the cistern. Allow it to dry. Detach the plastic nut from under the cistern. Unscrew the siphon and remove it. Fix a new siphon in its place.