We value simplicity here at Home Secure. No matter how technical or difficult a job may seem we like to get it down to the fundamentals for ourselves and for our customers. Replacing a multipoint uPVC door lock may seem like a daunting task but with the right tools and know how it is relatively simple.
If you already know which gearbox you need, browse our full range of replacement
multipoint door lock gearboxes — we stock centre cases for ERA, GU, Fullex, Maco, Mila
and more, with fast 2-day UK delivery.
Always try and replace your old gearbox with the exact same size and brand.
The Tools
All you need to replace your old uPVC mechanism with a new central gearbox is a screw driver or drill and a spare 5 minutes! As long as you have selected the correct size central gearbox you will have no difficulty in changing it over. For the professionals or expert DIY members among you it is a good idea to test out your handy work to see if your uPVC lock is functioning correctly. To do this it is always good to have a locksmith’s multipoint operating tool handy.
While you have the lock apart, it is a good time to check your euro cylinder too.
If your cylinder does not have anti-snap protection, upgrading to a TS007 3-Star anti-snap euro cylinder ensures the whole locking system is secure.
Understanding how multipoint locking mechanisms work is essential for anyone looking to improve the security of their uPVC or composite doors. As explained by Lock Guy, these systems use several locking points—typically hooks, bolts, or rollers—that engage simultaneously when the door handle is lifted. This design distributes pressure evenly along the door frame, making forced entry far more difficult than with a standard single-point lock. Homeowners are encouraged to check that their mechanisms are correctly aligned and serviced regularly, as even small misalignments can reduce locking efficiency over time. Regular maintenance ensures your door locks continue to meet UK security standards, keeping your home protected against modern burglary techniques.
Size
The main measurement you should be looking for on your uPVC gearbox replacement is the backset. The backset is the part of the mechanism that will be placed within the composite door. The depth of the backset can be measured from the edge of the gearbox case to the centre of the euro profile. The second measurement you need is the PZ measurement, this goes from the central euro profile to the top of the spindle.
Not sure which gearbox fits your door?
Our step-by-step guide on how to identify your uPVC multipoint door lock explains how to measure the backset, PZ centre and spindle type so you can order the correct replacement.
If your door handle also feels loose or worn, it may need replacing at the same time as the gearbox.
Browse our uPVC door handles for lever-lever and lever-pad options in all common PZ sizes.
See Fig.1 for the backset size and Fig.2 for the PZ size:
If the full multipoint locking strip needs replacing rather than just the gearbox, we stock a large range of full units at our Liverpool store.
Full multipoint locks are too long to ship but can be matched and purchased in-store at Home Secure, Unit 5 Brookfield Drive, Aintree, Liverpool L9 7AJ.
To see how to quickly and efficiently change over your old uPVC door lock with a new replacement central multipoint gearbox then take a look at our ‘uPVC Door Lock Multipoint Change Over’ video below:
For a complete overview of all the door locks and security products we stock, visit our high security door locks collection.
Check out the featured products from this article below 👇 Including Fuhr Door Lock Centre Case Gearbox
