How to Change a Mortise Lock Cylinder

PDF download Download Article
PDF download Download Article

Mortise locks are most commonly found in older homes and in commercial applications. There are many variations, but they all basically work the same. This guide should help you to be able to change the lock cylinder.

Steps

PDF download Download Article
  1. {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/1\/11\/Change-a-Mortise-Lock-Cylinder-Step-1.jpg\/v4-460px-Change-a-Mortise-Lock-Cylinder-Step-1.jpg","bigUrl":"\/images\/thumb\/1\/11\/Change-a-Mortise-Lock-Cylinder-Step-1.jpg\/aid5909-v4-728px-Change-a-Mortise-Lock-Cylinder-Step-1.jpg","smallWidth":460,"smallHeight":345,"bigWidth":728,"bigHeight":546,"licensing":"<div class=\"mw-parser-output\"><p>License: <a target=\"_blank\" rel=\"nofollow noreferrer noopener\" class=\"external text\" href=\"https:\/\/creativecommons.org\/licenses\/by-nc-sa\/3.0\/\">Creative Commons<\/a><br>\n<\/p><p><br \/>\n<\/p><\/div>"}
    Remove the two retaining screws and set aside.
  2. {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/0\/07\/Change-a-Mortise-Lock-Cylinder-Step-2.jpg\/v4-460px-Change-a-Mortise-Lock-Cylinder-Step-2.jpg","bigUrl":"\/images\/thumb\/0\/07\/Change-a-Mortise-Lock-Cylinder-Step-2.jpg\/aid5909-v4-728px-Change-a-Mortise-Lock-Cylinder-Step-2.jpg","smallWidth":460,"smallHeight":345,"bigWidth":728,"bigHeight":546,"licensing":"<div class=\"mw-parser-output\"><p>License: <a target=\"_blank\" rel=\"nofollow noreferrer noopener\" class=\"external text\" href=\"https:\/\/creativecommons.org\/licenses\/by-nc-sa\/3.0\/\">Creative Commons<\/a><br>\n<\/p><p><br \/>\n<\/p><\/div>"}
    Most likely it is at the bottom (six o'clock).
    Advertisement
  3. {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/9\/9d\/Change-a-Mortise-Lock-Cylinder-Step-3.jpg\/v4-460px-Change-a-Mortise-Lock-Cylinder-Step-3.jpg","bigUrl":"\/images\/thumb\/9\/9d\/Change-a-Mortise-Lock-Cylinder-Step-3.jpg\/aid5909-v4-728px-Change-a-Mortise-Lock-Cylinder-Step-3.jpg","smallWidth":460,"smallHeight":345,"bigWidth":728,"bigHeight":546,"licensing":"<div class=\"mw-parser-output\"><p>License: <a target=\"_blank\" rel=\"nofollow noreferrer noopener\" class=\"external text\" href=\"https:\/\/creativecommons.org\/licenses\/by-nc-sa\/3.0\/\">Creative Commons<\/a><br>\n<\/p><p><br \/>\n<\/p><\/div>"}
    On some applications there may be two set screws, one for the outer cylinder and one for the inner.
  4. {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/a\/ab\/Change-a-Mortise-Lock-Cylinder-Step-4.jpg\/v4-460px-Change-a-Mortise-Lock-Cylinder-Step-4.jpg","bigUrl":"\/images\/thumb\/a\/ab\/Change-a-Mortise-Lock-Cylinder-Step-4.jpg\/aid5909-v4-728px-Change-a-Mortise-Lock-Cylinder-Step-4.jpg","smallWidth":460,"smallHeight":345,"bigWidth":728,"bigHeight":546,"licensing":"<div class=\"mw-parser-output\"><p>License: <a target=\"_blank\" rel=\"nofollow noreferrer noopener\" class=\"external text\" href=\"https:\/\/creativecommons.org\/licenses\/by-nc-sa\/3.0\/\">Creative Commons<\/a><br>\n<\/p><p><br \/>\n<\/p><\/div>"}
  5. {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/c\/c6\/Change-a-Mortise-Lock-Cylinder-Step-5.jpg\/v4-460px-Change-a-Mortise-Lock-Cylinder-Step-5.jpg","bigUrl":"\/images\/thumb\/c\/c6\/Change-a-Mortise-Lock-Cylinder-Step-5.jpg\/aid5909-v4-728px-Change-a-Mortise-Lock-Cylinder-Step-5.jpg","smallWidth":460,"smallHeight":345,"bigWidth":728,"bigHeight":546,"licensing":"<div class=\"mw-parser-output\"><p>License: <a target=\"_blank\" rel=\"nofollow noreferrer noopener\" class=\"external text\" href=\"https:\/\/creativecommons.org\/licenses\/by-nc-sa\/3.0\/\">Creative Commons<\/a><br>\n<\/p><p><br \/>\n<\/p><\/div>"}
    Use extreme caution not to cross thread the cylinder as this may ruin the entire lock!
  6. {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/5\/55\/Change-a-Mortise-Lock-Cylinder-Step-6.jpg\/v4-460px-Change-a-Mortise-Lock-Cylinder-Step-6.jpg","bigUrl":"\/images\/thumb\/5\/55\/Change-a-Mortise-Lock-Cylinder-Step-6.jpg\/aid5909-v4-728px-Change-a-Mortise-Lock-Cylinder-Step-6.jpg","smallWidth":460,"smallHeight":345,"bigWidth":728,"bigHeight":546,"licensing":"<div class=\"mw-parser-output\"><p>License: <a target=\"_blank\" rel=\"nofollow noreferrer noopener\" class=\"external text\" href=\"https:\/\/creativecommons.org\/licenses\/by-nc-sa\/3.0\/\">Creative Commons<\/a><br>\n<\/p><p><br \/>\n<\/p><\/div>"}
    Set the cylinder so that the keyway is in the same position as it originally was, usually to the bottom, and tighten the set screw.
  7. {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/0\/03\/Change-a-Mortise-Lock-Cylinder-Step-7.jpg\/v4-460px-Change-a-Mortise-Lock-Cylinder-Step-7.jpg","bigUrl":"\/images\/thumb\/0\/03\/Change-a-Mortise-Lock-Cylinder-Step-7.jpg\/aid5909-v4-728px-Change-a-Mortise-Lock-Cylinder-Step-7.jpg","smallWidth":460,"smallHeight":345,"bigWidth":728,"bigHeight":546,"licensing":"<div class=\"mw-parser-output\"><p>License: <a target=\"_blank\" rel=\"nofollow noreferrer noopener\" class=\"external text\" href=\"https:\/\/creativecommons.org\/licenses\/by-nc-sa\/3.0\/\">Creative Commons<\/a><br>\n<\/p><p><br \/>\n<\/p><\/div>"}
    You may have to back out the new cylinder a turn or two so that everything works smoothly. The store where the cylinder was purchased will have trim rings that will compensate for this.Once the lock is functioning properly, re-install the cover plate at the edge of the door.
    8. Advertisement


Expert Q&A

Ask a Question
200 characters left
Include your email address to get a message when this question is answered.
Submit
      Advertisement

      Tips

      • Purchase a few trim rings of different depths when you buy the new cylinder. You can make one trip to return them once you're finished rather than running back and forth and having to disassemble the lock multiple times.
        Thanks
      • You can purchase cylinders that do not require keys to operate them to install on the inside if you have inner cylinders. Keep in mind that you may want keyed inner cylinders if you have a window or side lite in your door.
        Thanks
      Submit a Tip
      All tip submissions are carefully reviewed before being published
      Submit
      Thanks for submitting a tip for review!
      Advertisement

      Warnings

      • Be sure to tighten your set screw. If the set screw is not tightened the cylinder may be easily unscrewed from the lock body and security will be compromised.
        Thanks
      • If you have keyed inner cylinders you MUST keep a key within easy reach in case of emergency. You may want to tape it to a fire extinguisher or emergency flashlight. You should inform your personnel and anyone who may be locked inside your structure where these emergency keys are. THE KEY SHOULD BE AN ORIGINAL AND NOT A DUPLICATE!!!!
        Thanks
      Advertisement

      You Might Also Like

      How to
      Burglarproof Your Doors
      How to Remove and Install a Door Lock (with Pictures)
      How to
      Make a Padlock Shim
      How to
      Remove Sliding Glass Shower Doors
      How to
      Reset a Luggage Lock
      How to
      Unlock a Door
      How to
      Break a Lock
      How to Reprogram a Sentry Safe with or without the Factory Code
      How to
      Open a Door with a Credit Card
      A Detailed Guide to Programming Car Keys & Fobs
      How to
      Open Combination Locks Without a Code
      How to Unlock a Safe: Combination Locks, Digital Locks & More
      Don’t Panic! What to Do When You’ve Locked Your Keys inside Your Car
      How to
      Open a Locked Bathroom Door
      Advertisement

      About This Article

      Thanks to all authors for creating a page that has been read 149,539 times.

      Did this article help you?

      Advertisement