How to change Euro-cylinder locks, What you need to know.
Updating or improving your home security doesn’t always have to be expensive or need a specialist to install the latest high-tech alarm. After a recent break-in, I needed to replace the lock of my uPVC kitchen door, this type of door is usually fitted with a Euro-cylinder lock.
I did some research and found it was a straightforward job and you can also upgrade your security as you go, here are my tips to replace a Euro cylinder door lock:
Open the door and undo the central locating screw with a cross-head screwdriver, put the key in the lock and rotate until it aligns the cam inside, then slide the lock from the door, measure its length, and replace it with a new upgraded lock. Slide the lock back into the door and replace the locating screw, and test to check it works.
Euro locks are used on all sorts of doors and replacing them is an easy task to do, for a beginner at DIY, whilst you have the old lock removed, it s a good idea to upgrade and improve your home security, read the steps and recommendations in the post below for more details.
Tools you will need to replace a Euro-cylinder lock:
How to remove a Euro cylinder Lock
First, open the door to access the narrow edge of the latch stile, this is the face of the door which closes against the door frame with the handle and locks.
Locate the door lock and the central locating screw, these are usually long M5 threaded machine screws, that pass through the door and into the lock holding it in place.
Using a Philips or cross-head screwdriver undo the locating screw. if this is a bit tight apply some WD 40 or GT 85 lubricant to help loosen the screw, remember to turn the screw anti-clockwise to undo it.
Next, align the lock cam with the lock body, and make sure the key is in the lock, as this will be needed to turn the cam. This can take a bit of wiggling, by applying a gentle pulling force on the key it will slide out once the cam aligns with the lock body and door frame.
If the lock is tight or stops you may need to loosen the door handles first as they can be tight.
You can then pull the Euro cylinder lock barrel from the door.
With the Euro cylinder removed from the door, you can clean or replace it. I recommend checking the type of lock you have fitted and where possible upgrading to the latest high-security types, which offer more protection and help deter entry.
Read our guide to upgrading euro-cylinder locks and find out how you can improve your home security.
To replace a lock you need to know how long it is and what type use our handy guide to find out more about how to measure a euro-cylinder door lock and what types are available.
Take a look at the video below for more on these steps:
Video: How to fit a Euro-cylinder lock
How to refit a Euro cylinder lock
Refitting a new lock in a uPVC door is simply the reverse of taking it out, firstly fit the key and align the cam so that it will fit into the lock mechanism and door frame.
Then push the new lock barrel into the door, high security locks can only go in one way and are usually marked to tell you which side faces the exterior of the door.
Line up the locating hole in the block barrel with the hole in the door lock mechanism and gently screw in the M5 locating screw.
Once you have the thread started use a Philip’s or cross head screwdriver to tighten the locating screw.
if you have removed the handle refit them first before you tighten the lock in place as this allows the lock to move around and properly align with the door and handles.
Check and tighten the lock and handles
With everything in the right place, Check the handles operate and are not stiff, check the key turns the lock and the bolt is thrown fully, once you are happy this all working properly tighten all the screws.
I like to add a quick squirt of lubricant, such as GT85 or WD 40 before I lock everything down tight as it helps the handle and lock to move freely. I then double check the handles operate without issue, checking for sticking or any fouling as you turn the handle.
Then I recommend you check the door shuts properly and that the multipoint system works (usually by lifting the handle upwards but check your door manufacturer’s manual to be sure).
When you are confident the door works, open the door and try turning the key in the lock a few times.
Then close the door and lock it, checking it is secure. I always try opening, closing, locking, and unlocking it a few times to make sure.
Once you are happy that everything works, give the door a good wipe with a clean rag.

This article was written by: Richard Quinton – The DIY Help Desk Owner, Engineer & technical specialist.
Richard is one of the key partners in The DIY Help Desk team. He is a qualified Engineer, writer, and publisher, educated to Master’s level. He is a keen advocate of DIY and home improvements.
Richard enjoys helping others to learn new skills and reach their goals and believes that passing his knowledge and experience on through his writing is an effective way to positively impact the lifestyles and well-being of others on a larger scale.