How to change a euro cylinder lock

How to change a euro cylinder lock

Michael, Professional and passionate welder, Sheffield

Guide written by:

Michael, Professional and passionate welder, Sheffield

68 guides

Changing a euro cylinder lock should be quick and easy. Fitted into the door handle, these locks feature a cam tongue and are secured via a fixing screw on the side of the door. While these locks can vary in size (e.g. 30-30, 30-40), the process is always the same. Read on to learn how to replace a euro cylinder lock.

Important features

  • Removing the old euro cylinder lock
  • Measuring the cylinder lock barrel
  • Fitting the new euro cylinder lock
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Replacing a cylinder lock for maintenance and/or safety reasons

A euro cylinder lock is a secure lock mechanism that moves independently from the door as you turn your key. It is advisable to replace your euro cylinder lock in a number of situations:

  • when moving into a new home. Even if all the keys have been returned, it's a good idea for new occupants to replace the existing locking system for any exterior doors (e.g. entrances, back doors, etc.);
  • if your euro cylinder lock tends to jam when locking and unlocking the door;
  • in order to conform to certain safety standards. It's important to note that some insurance companies specify lock requirements in their policies and a non-regulation lock can invalidate a claim in the event of a break-in;
  • to enhance security with an A2P security lock.

After removing the old lock, you will have to choose a replacement lock to fit your door, the lock system in place and any particular safety concerns you may have.


  1. Removing the old euro cylinder lock
  2. Measuring the cylinder lock barrel
  3. Fitting the new euro cylinder lock

Required skills

Replacing an old euro cylinder lock is straightforward and doesn't require any particular skills beyond using a screwdriver and taking some measurements.

Completion time

Around 10 to 30 minutes

Number of people required

1 person

Tools and equipment

Personal protective equipment (PPE)

  • Work clothes
  • Protective goggles
  • Protective gloves

This is a non-exhaustive list; be sure to match your personal protective equipment to the job at hand.

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Penetrating oil

1. Removing the old cylinder lock

Locate the lock fixing screw on the side of the door. Use a screwdriver to fully unscrew the fixing screw. If your lock is old, you may need to spray in some penetrating oil and wait a few minutes before removing the screw.

Insert the key into the euro cylinder lock and twist it about a quarter of a turn to line up the cam tongue (the moving part of the lock) with the body of the lock. Then, work to remove the barrel.

Please note: the fixing screw can sometimes break completely which will make the task harder. In this case, you can drill into the screwand use a screw extractor to remove the broken piece.

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Screw extractor

2. Measuring the cylinder lock barrel

Euro cylinder locks usually conform to standard sizes and are therefore easy to replace. However, the length may vary depending on the thickness of the door (e.g. 30-30 or 30-40).When replacing an old lock, it is essential to take measurements.

  • Measure the length of the euro locking cylinder from the screw hole in the centre to each end of the lock barrel.
  • Note down these measurements in order to choose the right size of lock.
  • If the lock is assymetric or if the new lock comes with a thumb turn, you must take this into consideration. It is not possible to reverse an assymetric euro cylinder lock.
  • Your euro cylinder lock must not overhang the door on the outside in order to prevent potential intruders getting a grip on the lock and prying it off.
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Euro cylinder locks

3. Fitting the new cylinder lock

  • Place the key in the lock and turn it to line up the cam tongue and lock body.
  • Insert the euro cylinder lock into the open door. Do not force the lock: if the hole is a little tight, you can file it down slightly using a round file .
  • Euro cylinder locks have a screw hole in the centre for fitting the fixing screw. Screw the fixing screw into the hole and secure it using a screwdriver.
  • Finish by oiling all moving parts.
  • You can now test out your new euro cylinder lock.
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Guide written by:

Michael, Professional and passionate welder, Sheffield, 68 guides

Michael, Professional and passionate welder, Sheffield

I was trained as a pipe worker and a pipe-welder and after having traveled for 35 years working around the UK, I became the head a metal shop and then a designer and in the end the head engineer. I have designed and built a workshop where I make metal sculptures: I managed to find a piece of paradise where I can to let my imagination run wild. Auctions and garage sales are no secret to me. I find unusual objects and old tools there that I collect or transform into works of art. I also like decoration, painting on canvas, and gardening. I am developing new technologies concerning tools. To share my passion and humbly advise you in your choice of materials is a real pleasure.

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