Step 4: Replace the old gasket with a new one that is identical. New gaskets that are almost perfectly matched to the old gaskets generally allow the faucet to no longer drip. You should also note that the old gasket is either beveled or flat and replaced with the same new gasket. A gasket designed only for cold water will swell significantly when hot water flows to block the water outlet, making the hot water flow slower. Some washers work in hot and cold water, but make sure that the gasket you bought for replacement is exactly the same.
Step 5: Secure the new gasket to the valve plug and reassemble the parts in the faucet. Rotate the cartridge clockwise. After the cartridge is in place, reinstall the packing nut. Be careful not to leave the wrench scratched on the metal.
Step 6: Reinstall the handle and replace the button or disc. Re-open the water supply and check for leaks.