If a single-handle faucet makes noise when it is operating or if it is hard to turn, it may need to be lubricated. Lubricating a single-handle faucet is not that hard to do and can save money over buying a new faucet or having a plumber out to do the same. The main parts of a single-handle faucet are the cartridge, a seat, a washer and a retaining clip which holds the cartridge in place. Lubricating the faucet involves all these parts.
Turn off the water supply to the faucet by turning the shut offs under the sink all the way to the right. If there are no individual shut-offs under the sink then use the main water shut-off for the entire house.
Loosen the Allen screw located at the base of the faucet handle and pull off the handle.
Remove the washer that is directly under the handle.
Remove the retaining clip that holds in the cartridge. A pair of needle-nose pliers should work well for this task.
Pull the cartridge out with regular pliers. It may be stuck so it may take some pulling to get it out.
Remove the round brass seat that is directly under the cartridge with the needle-nose pliers.
Place grease into the hole and grease each part that was removed.
Reassemble all the parts by reversing the process that you used to remove them. Turn on the water.