The fault lies not in your gleaming faucet set, but in the workings out of sight. Since you have access to the back and underside of the sink, use a flashlight and look for a vertical metal rod projecting below the back of the basin—the working part of the stop- per handle. It should be attached to a horizontal pivot rod with a spring clip. The pivot rod runs through the sink’s drainpipe, where it’s connected by a retaining nut that keeps the joint watertight. The pivot rod connects to the bottom of the stopper inside the drain- pipe. Together, the handle and pivot rod move up and down like a seesaw whenever you push on the stopper.
If the stopper won’t stay in place, the solution could be as simple as ad- justing the stopper level. (The plumber may not have checked the adjustment.) Underneath the sink, locate the point at which the rear end of the horizontal pivot rod attaches to the vertical stopper handle. There should be a flat metal bar with several holes in it. This is called a clevis.
To make the stopper rise higher when open, squeeze the bendable clip holding the pivot rod to the clevis, then slip out the pivot rod and move it down a hole or two on the clevis. To make the stopper close more tightly, move the pivot rod up a hole or two. If there’s no clevis, simply loosen the fitting or clamp joining the rods and move the pivot rod up or down on the handle rod as needed.
Or maybe the stopper is the problem. To replace damaged parts, remove the retaining nut at the back of the drain. Then pull the pivot rod out to release the stopper. If the rub- ber gasket around the bottom of the plug is worn or cracked, replace it or the entire stopper. Take it to a good hardware store and buy a comparable product.