The Moen 7400 series of faucets includes the popular Chateau kitchen faucet, which is a single lever faucet. This faucet, like many other Moen models, may begin to leak or have water flow issues after assembly. If this is the case, a disassembly of the faucet and re-tightening of the parts is all you need to do to correct the problem. It takes just a few minutes and will not require extensive plumbing experience.
Turn off the water supply to the faucet by shutting the valves on the to water pipes directly under the faucet in your sink cabinet.
Take off the single lever handle on the Moen faucet. First take out the screw in front of the handle along the base with an Allen wrench. If there is a plug in the mounting hole, take this out before unscrewing the handle.
Remove the faucet dome, the large, round piece under the handle by turning it counterclockwise and lifting it up. Unscrew the cartridge retainer nut under the dome with a pair of locking pliers or a hexagonal wrench, properly sized to fit the nut.
Lift the cartridge out of the faucet base with your hands, or a pair of pliers if necessary, and insert a new one in place of it. Make sure the cartridge rests flush against the base of the faucet and install the cartridge retainer nut, turning clockwise to tighten it.
Replace the dome and turn clockwise to install it on the faucet base. Slide the handle onto the spout and tighten the set screw to hold it in place.