Gather the Pieces Together
Before you start reassembling the Moen faucet aerator, make sure that your parts are in front of you. These parts include the metal cap, the metal screen, the plastic screen, mixer and the rubber washers. Place all these parts on a flat surface before you begin the job.
The Metal Pieces
With all the parts in front of you, start by slotting together the metal pieces. Assemble the aerator in the metal cap that will be fixed on the faucet. Hold the metal cap in your left hand and insert the metal screen. Gently press the screen until it reaches the bottom of the cap.
The Rubber Pieces
After having inserted the metal screen, insert the air and water mixer into the cap. Make sure both the screen and the mixer are the correct way up, with the mixer pointing in the direction of the water flow.
The Rubber Washer
After having inserted the screen and the air and water mixer, place the rubber washers into the aerator cap. Make sure that this piece is also the right way up, otherwise you will be unable to fix the aerator tightly over the faucet, and water may also start to leak out. Even a worn washer can cause these problems, so make sure the rubber washer is in good shape before you insert it into the aerator.
Fit Back on the Faucet
Now you have all the parts of aerator reassembled, screw it onto the faucet. Tighten the aerator first by hand and then screw it down properly with the help of a pair of pliers. If you will not screw the aerator properly onto the faucet, water may leak out of it.