If your faucet handle turns too far, it probably means that the interlocking knurls on either your faucet handle or faucet cartridge have become worn. It is common for a faucet with lever-style handles to become so worn over time that the faucet turns past the "off" position, or to have a faucet handle that turns in the wrong direction. The good news is that this is usually an easy repair that requires just a few basic tools.
Temporary Faucet Handle Repairs
When the faucet cartridge becomes stripped, your faucet handle turns too far, sometimes resulting in a faucet that turns past the "off" position. This can be extremely annoying, especially if you can't get the water to turn on or shut off. One simple temporary repair is to install a universal faucet handle. These are designed to fit most faucets, but they probably won't match your faucet — and they don't last forever.
Another temporary repair is to remove the faucet handle and wrap Teflon tape around the knurls of the internal stem on the faucet cartridge. This solution will give the knurls inside your faucet handle something to grip on to and allow it to turn. Like installing a universal faucet handle, this is only a temporary answer if your faucet handle turns too far. It is not a long-term solution.
If Your Faucet Turns Past “Off” Position
Close the drain or cover it with a towel to avoid losing screws and other small parts. Remove the decorative cap on the faucet handle to access the handle screw. The cap can be pried off with a flat-head screwdriver. If the faucet handle is loose, tighten the screw until it is snug by turning it clockwise with a Phillips screwdriver. Avoid overtightening the screw, as this can cause it to strip or break.
If tightening the handle screw does not solve the problem, remove the screw by turning counterclockwise. Pull the handle off and inspect the interlocking notches inside the handle and on the faucet cartridge. If they don't appear worn, set the handle back onto the cartridge with the notches in a slightly different position and turn to see if the faucet turns past the "off" position. If there is still a problem, remove the handle again.
Replacing the Faucet Cartridge
Turn off the water to the faucet with the shut-off valves below the sink. Open the faucet until the water drains out. Remove the locking nut by turning counterclockwise with an adjustable wrench or a pair of channel-lock pliers. Take out the faucet cartridge by lifting it out. If there is resistance, you can pull it gently with channel-lock pliers, or by reattaching the handle with the screw and pulling.
Install a new cartridge to replace the old one. These can be purchased at a hardware store or a home improvement store, such as Lowe's. Be sure the cartridge is installed exactly like the old cartridge to avoid having a faucet handle that turns in the wrong direction. Screw on the retaining nut and tighten it with an adjustable wrench.
Replace the handle, tighten the screw, and put on the decorative cap. Turn on the water at the valves under the sink and check for leaks while making sure you don't have a faucet handle that turns too far or the wrong way.