There’s a simple secret here: You need to use a basin wrench, available at most home centers. The head works on a cam principle, tightening around any size nut as you turn the handle. The head is mounted on the end of a long handle; it flips to allow you to turn clockwise or counterclockwise.
To remove the old faucet, close the shutoff valves under the sink. Next, use the basin wrench to remove the coupling nuts that secure the water-supply tubes to the faucet and to loosen the mounting nuts that secure the faucet to the sink or countertop. You’ll also need to disconnect the pop-up drain linkage from the sink drain by removing the retaining nut.
Before you position the new faucet, press some plumber’s putty all around the underside along the outer edge. After you make your connections, clean off the excess putty with a plastic putty knife or rag.
