Things You'll Need
Lock re-keying kit
Having a lock that does not operate correctly is frustrating as well as potentially dangerous. Most issue with Kwikset door lock cylinders involve the pins that react with the key. When the pins wear down, your key begins to not work with the lock. You can repair the Kwikset lock cylinder by re-keying the cylinder. Re-keying kits are available at home improvement centers as well as from Kwikset. When purchasing a kit at a home improvement store, ensure that you purchase a kit for Kwikset locks.
Remove the outside door knob assembly from the door. Some models have a small pin on the neck of the inner door knob. Push the pin in with a paper clip to disconnect the door knobs. Most models will have two screws on the inside doorknob that you remove with a Phillips-head screwdriver.
Push the small spring housing away from the cylinder on the inside of the door knob with the cylinder plug tool that comes with the kit. The plug tool resembles a round tube with a fork on one end. Use the fork end to pry the retaining ring from the cylinder and pull the cylinder away from the doorknob.
Place the flat retaining ring tool that comes with the kit around the retaining ring on the back of the cylinder. Hold the cylinder with one hand while popping the retainer off with the retaining tool.
Insert the cylinder plug tool in the back of the cylinder and begin pushing the cylinder plug out of the cylinder housing. The plug contains the pins that you will be replacing. Maintain pressure on the plug tool while pushing the cylinder plug. The plug tool will keep the cylinder springs from falling.
Turn the cylinder plug over and dump out the pins. Insert the new key that comes with the kit and use needle-nose pliers to set the new pins into the cylinder plug. A code sheet will come with the kit to indicate what color pins go into each cylinder hole for the key. The pins should be flush across the cylinder.
Push the cylinder plug back into the cylinder. Place the back of the plug against the end of the plug tool and push the plug tool out. This will keep pressure inside the cylinder housing and keep the springs on the housing from falling.
Pop the retainer back over the end of the cylinder. Insert the cylinder into the door knob and secure the cylinder to the door knob with the retaining clip. Reattach the inner and outer door knob to the door using the retaining screws or pin.