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How to Replace a Door Lock

Learn how to replace a door lock with measuring, removing old hardware, installing latch and strike, testing keys, mistakes, troubleshooting, and FAQs.

Home & RepairsEdited by Pramod Tiwari
2 min read

Quick Answer

To replace a door lock, buy a lock that matches the door thickness, backset, and bore, remove the old screws and hardware, install the new latch, exterior and interior lock pieces, tighten screws evenly, install or adjust the strike plate, and test the key and latch before closing the door.

Tools and Materials

  • Replacement lockset or deadbolt
  • Screwdriver
  • Tape measure
  • Pencil
  • Chisel optional
  • Drill optional
  • Safety glasses optional

Safety Precautions

  • Do not leave an exterior door unsecured during the project.
  • Keep keys accessible before closing the door.
  • Use a licensed locksmith for high-security locks, damaged doors, or uncertain fit.
  • Avoid very low quote locksmith scams; verify business identity and pricing before emergency service.
  • Wear eye protection if drilling or chiseling.

Step-by-Step Instructions

  1. Step 1

    Measure existing lock

    Check door thickness, bore size, and backset.

  2. Step 2

    Remove old hardware

    Unscrew interior screws and pull lock pieces away.

  3. Step 3

    Remove latch

    Unscrew the edge latch and slide it out.

  4. Step 4

    Install new latch

    Insert the latch with bevel facing the correct direction.

  5. Step 5

    Attach lock halves

    Align exterior and interior pieces through the latch.

  6. Step 6

    Tighten screws

    Tighten evenly without binding the latch.

  7. Step 7

    Install strike

    Replace or adjust the strike plate and test with the door open.

  8. Step 8

    Test fully

    Test key, thumb turn, latch, and deadbolt before closing.

Practical Example

Example: You replace a worn entry knob with the same backset, install the latch and knob halves, tighten screws, then test the key with the door open.

Common Mistakes

  • Buying wrong backset
  • Closing door before testing
  • Installing latch backwards
  • Overtightening screws
  • Ignoring misaligned strike plate
  • Leaving exterior door unsecured

Troubleshooting

Key turns but latch sticks

Loosen screws slightly and check latch alignment.

Deadbolt does not extend fully

Adjust or deepen the strike opening.

Door holes do not match

Return for a compatible lock or use proper boring tools.

You are locked out

Call a verified locksmith and confirm pricing before work begins.

FAQs

Can I replace a door lock myself?

Yes, if the new lock matches the existing door prep.

What is backset?

The distance from the door edge to the center of the lock hole.

Should I rekey or replace?

Rekeying can be enough if the lock works and you only need new keys.

When should I call a locksmith?

Use a locksmith for high-security hardware, damaged doors, lockouts, or uncertain installation.

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