When moving into an older home, you will find many things that need to be replaced. This will include certain plumbing endeavors, most likely the faucets. Problems can be as minor as worn threads leading to annoying leaks to just a need to modernize your look. This can be only slightly more trouble than repairing leaks but it more than worth it in the long run.
To get a component that fits your fixture, measure the distance separating the centers of the holes in the fixture for the tailpiece connections. It is simple to find single-lever faucets at local discount stores for a 3-hole setup with a 4-inch hole separation and three-and four-hole sinks with 6 or 8-inch separations. However, this will not apply to fixtures that are connected vertically on the wall (which were popular in houses in 1920’s-1940’s) rather than horizontal fixtures.
If the new fixture has holes that don’t match, use individual faucets as replacements. It will be more trouble than it is worth to attempt to adapt a fixture to a single-lever faucet that isn’t intended to fit it.
Removing the old setup.
After turning off the water, unfasten the tailpiece coupling nuts. You may be able to reach these with locking pliers or an adjustable wrench, but the space between basin and wall is generally so small that a basin wrench is needed. You will now remove the old pop-up drain. Then unscrew the lock nuts, slide the washers down, pull off the old faucets and remove the tailpieces. Now you will have to use two pipe wrenches to unscrew threaded joints.
Now is the time to do some straightening.
Straightening the water supply tubes, that is; gently unbend the tubes of the new faucet so they can slide through the center sink hose. Lay the faucet on a table or floor and straighten each tube and make sure not to make kinks in the tubing. On a sink faucet, these tubes are next to the mounting studs and go through the out holes. These normally do not need straightening.
Putting the faucet in.
If your new faucet has a spray hose then set it first. Slip the hose down through the hole in the faucet assembly and gasket, then through its own hole in the sink. Then put it through the center hole in the sink. Attach the hose nut to the supply stub on the faucet with an adjustable wrench. If your setup doesn’t come with a gasket then seal the fixture holes with plumber’s putty.
Now you can slide the tubes and threaded mounting studs through the fixture holes. Place the washers and nuts on the studs from underneath and position the faucet. Then tighten the nuts first with your fingers and, secondly, with a wrench. Tightening with your fingers ensures that it will stay. Using the wrench first you run the risk of losing both washers and nuts.
Reconnecting the supply tubes.
Gently bend the supply tubes so that they will line up with the shutoff valve connectors. Supply tubes and connections are joined with compression couplings. You may need adapters to fit threaded parts to unthreaded tubing. Now is the time to install the pop-up drain. When all joints are tightened, turn the water back on, remove the aerator from the spout and run hot and cold water hard for several minutes to wash out the lines and check for leaks.