<p>Float valve repair usually means replacing a faulty ballcock in a toilet or tank, a DIY-friendly job involving turning off water, disconnecting the old valve (often by loosening a large nut with pliers/spanner), installing the new one (ensuring the rubber washer is in place), reattaching the float, and testing, which often solves constant dripping or running water issues by replacing worn internal parts or the whole unit. For engine valve float, it's a more complex repair involving stronger springs to prevent valve-to-piston contact at high RPMs.&nbsp;<br><br><strong>Shut off Water:</strong> Locate the stopcock or a local ball valve and turn off the cold water supply to the tank/cistern.</p><ol><li><strong>Drain Tank:</strong> Flush the toilet or bail out water until the tank is partly empty.</li><li><strong>Remove Old Valve:</strong> Use pliers and a spanner to loosen the large nut connecting the valve to the tank, holding the valve body to prevent twisting.</li><li><strong>Inspect/Replace Parts:</strong><ul><li><strong>Washer:</strong> Check the rubber washer inside the nut; if worn, replace it (often part of a repair kit).</li><li><strong>Float:</strong> Check the ball float for leaks (if it has water inside, it's faulty and needs replacing).</li><li><strong>Full Replacement:</strong> Often easier to install a new universal float valve unit.</li></ul></li><li><strong>Install New Valve:</strong> Position the new valve, tighten the nut (don't overtighten), reconnect the water feed pipe carefully.</li><li><strong>Adjust &amp; Test:</strong> Turn water back on, adjust the float arm to set the correct water level (just below the overflow pipe), and check for leaks.</li></ol>