Remove the Old Lock

• 1). Remove the faceplate screws from both sides of the door and the edge plate, then remove the trim.
  
  
• 2). Remove the lock case screws and pull the lock case.
  
  
• 3). Cover a pair of pliers with electrical tape, then unscrew the cylinder and remove the internal assembly.
  
  
• 4). Measure the holes in the door to determine what size lock and trim you will need.
  
  

Replacing Lock

• 1). Insert the lock case into the hole left by the old lock.
  
  
• 2). Replace the securing screws and the plate.
  
  
• 3). Screw the lock cylinder into the hole or secure it with trim screws.
  
  
• 4). Insert the lock assembly into the existing hole, secure it with screws and install the new faceplate.
  
  

Patching the Hole

• 1). Measure the holes that need to be patched, including the hole on the door edge that used to house the lock cylinder and any holes in the door facing. Measure the width of the door.
  
  
• 2). Purchase some wood pieces or obtain some scrap wood, measure it and cut it to size.
  
  
• 3). Apply some wood epoxy to the edges and back of the wood and press the pieces into the holes.
  
  
• 4). Allow the patches to dry. Screw the solid trim piece to the door, covering the patch.
  
  

Installing New Lock

• 1). Tape the paper template over the section of the door where you want the new lock installed.
  
  
• 2). Mark the center of the holes that needs to be drilled with an awl, and mark where the strike plate needs to go.
  
  
• 3). Fit an electric drill with the appropriate-sized hole saw bit and drill through the center of the hole on both the edge and facing of the door.
  
  
• 4). Insert the lock assembly through the holes and secure with screws.
  
  
• 5). Cut around the spot in the door trim where the strike plate needs to go. Remove the wood carefully with the the utility knife and chisel. Install the strike plate and secure it with trim screws.