You do not have to be a contortionist to replace a leaky faucet on top mounted single or double kitchen sinks. The entire procedure can be completed in two hours or less if you follow these steps:
1. Turn off the water supply.
2. Loosen the ring that connects the ABS trap to the waste pipe, remembering the rule “lefty loosey and righty tighty.” You should be able to unscrew the ring by hand, however, in some cases the gentle use of a pipe wrench may be required to get it started.
3. Remove the brackets on the underside of the sink that hold it to the countertop with a flat screwdriver, 3/8-inch wrench or 3/8-inch ratchet. Put the brackets aside for re-installation.
4. If the faucets are old, they may be connected to the water lines with compression fittings and flexible metal pipes. In this case, cut the pipes with metal snips; do not attempt to loosen the corroded nuts that attach the pipes to the taps, unless your body is made of rubber and you love a futile challenge.
Newer installations should have braided steel hoses that are easy to disconnect from accessible inlet pipes or shut off valves with a 5/8-inch open-end wrench.
5. With the pipes cut or unhooked, the trap unscrewed and the brackets removed, use a flashlight or trouble light to examine the underside of the faucet. You will see two polymer nuts, each with four or more wings, threaded around the tap inlet pipes. When the faucet was originally installed, these nuts were hand tightened to seal the fixture to the upper side of the sink. However, after years of corrosion, they can be difficult to unscrew. In fact, the wings may break off in the process.
I’ve found the easiest way to get rid of these nuisances is to melt them off with a propane plumber’s torch set at low flame. (Keep a fire extinguisher nearby and wear a mask to prevent inhalation of fumes.)
6. With the wing nuts gone, it is now possible to remove the sink and faucet from the countertop. Push the sink upward from the underside to break the caulking seal between the sink’s lip and the countertop. Use a scraper to remove the old sealant before you reinstall it. (Silicone is best.)
7. Place the sink with the attached faucet upside down on a work table. You now have easy access to the nuts that hold the compression fittings to the threaded hot and cold tap inlets. (Braided hoses have similar sized nuts.)
Sometimes, these connectors have become “welded” in place by corrosion and require a shot of penetrating oil and the application of a little heat from a torch to loosen them to the point where a 7/8-inch open-end wrench will remove them.
8. You have now completed the most difficult part of the job. Install your new fixture (be sure it is compatible with your sink; most taps are four-inch O.C. from the faucet) by reversing the above steps. You will have to reach behind the sink to hand tighten the new polymer wing nuts sufficiently to seal the rubber or plastic pad between the faucet’s base and the sink’s back lip.
9. In place of compression fittings and flexible metal pipes, use steel braided hoses that screw on to the three-quarter-inch male fittings of the taps and the half-inch male fittings of the water supply lines or shut off valves. To ensure against leaks, wrap Teflon tape around the male threads in the same direction as the female connector tightens (righty tighty). The new nuts can be hand tightened on to the threaded tap pipes for most of the way, but an open-end wrench or a basin wrench is required to tighten the final rounds to prevent leaks.
10. If you don’t have shut off valves on your hot and cold inlet pipes, you can add them with a slick device known as a Shark Bite. The fitting is available in straight or elbow styles and is designed to accept half-inch copper, PEX or CPVC pipe. One end has a half-inch male thread to accept tap lines and the other has a fitting that slides onto any of the above named pipes and locks into position. The gadget includes a handy quarter-turn valve to open or close your water supply lines. The end that slides over the pipe can be removed with a simple tool sold with the valve, while the valve can be replaced by sliding the self-locking orifice back over the pipe.
I must admit that I was leery of a Shark Bite’s ability to seal a water line under pressure without leaking, so I experimented by installing them on the hot and cold inlet pipes that supply my kitchen sink.
An important requirement is that the ends of the half-inch pipes are cut square and burrs are removed with a file. Equally important is for the pipes to extend an inch into the valves’ orifices. I learned by trial and error that failure to seat the pipes to the correct depth results in a serious leak. The trick is to place a one-inch mark on each pipe, then push it into the valve with sufficient force to ensure that the pipe is fully seated at the mark.
Apparently, this easy-to-install invention was adopted for home plumbing from submarine technology, though I suspect the valve was not used in those leaky subs Canada purchased from Britain several years back.