What Is a Multipoint Locking System?
Most modern uPVC and composite front and back doors are fitted with a multipoint locking system. Unlike a traditional single-point lock that has one bolt, a multipoint system has multiple locking points that engage simultaneously when you lift the door handle and turn the key.
A typical multipoint locking system consists of several components working together:
The gearbox — the central drive unit that converts handle movement into bolt extension. This is the component that fails most often.
The locking strip — a long metal strip running the full height of the door edge containing all the bolt components: hooks, deadbolts, rollers and mushroom cams.
The cylinder — the barrel the key goes into. Separate from the gearbox. A cylinder fault is a different problem from a gearbox fault.
The keep plates — the receivers on the door frame into which the bolts extend when the door is locked. Alignment with these is critical.
The handle and spindle — the handle connects to the gearbox via the spindle. If the spindle snaps, the handle moves freely without operating the gearbox.
The slave gearbox — some doors have a secondary slave unit that assists the main gearbox. When only some bolts fail to engage, the slave is often the issue.
Understanding which component has failed is the difference between a quick gearbox swap and an unnecessary full mechanism replacement. LockFirst diagnoses the exact fault before recommending any repair.
Is It the Gearbox, the Cylinder or Something Else?
The symptoms your door is showing point directly to which component has failed. Here is the diagnostic guide LockFirst locksmiths use on every job across London:
What you are experiencing
Gearbox Replacement in London — What the Job Involves
A gearbox replacement is the most common multipoint lock repair we carry out across London. Despite sounding complex, it is a straightforward job for an experienced locksmith and is completed on the same visit in the vast majority of cases.
We test the door systematically to confirm the gearbox is the fault rather than the cylinder, the spindle or a frame alignment issue. The right diagnosis means the right fix first time.
Gearboxes are not universal. The replacement must match the original in terms of the backset, the case size, the follower size and the fixing positions. We measure and confirm the correct unit before removing the original.
The door edge strip is carefully removed. The failed gearbox is unbolted from inside the door edge and disconnected from the locking strip.
The new gearbox is fitted, connected and the door edge strip replaced. We test every locking point on the door not just the handle movement to confirm the full mechanism is operating correctly.
Once the mechanism is confirmed working, we check the door alignment and adjust the keep plates if needed to ensure all bolts engage cleanly. A misaligned door puts unnecessary strain on a new gearbox and shortens its life.
We carry GU Hardware, Mila, Fullex and Winkhaus gearboxes on every van across London. For less common or older mechanisms we may need to source a compatible unit, but we confirm this before attending and most standard gearboxes are completed same day.
Do You Need a New Gearbox or a Complete Mechanism Replacement?
This is the question that saves our customers money on almost every multipoint repair job across London. Most people assume that if the door won’t lock, the entire locking mechanism needs replacing. In the majority of cases, only the gearbox does.
Gearbox only is usually right when:
Full mechanism replacement may be needed when:
On every job, LockFirst assesses which applies before recommending anything. We never replace a full mechanism when only the gearbox has failed.
Should I Replace Like-for-Like or Upgrade?
This is something no other locksmith page explains and it matters, particularly for heavily used doors.
Many mid-range uPVC doors across London are fitted at the factory with budget gearboxes containing a high proportion of plastic internal components. These meet minimum standards but have a shorter lifespan under heavy use. When replacing a failed gearbox, you have the choice of a like-for-like replacement or an upgrade to a higher-specification unit with better steel content and tighter tolerances.
When a gearbox upgrade is worth considering:
LockFirst carries both standard replacement and upgraded gearboxes for the most common mechanisms across London. We will advise honestly on which is appropriate for your door and usage, with the price for both options before you decide.
Multipoint Lock Repair Across All Door Types in London
The gearbox — the central drive unit that converts handle movement into bolt extension. This is the component that fails most often.
Composite doors increasingly common in newer London properties and new-build estates across Cricklewood, Golders Green, Hampstead, Belsize Park, Swiss Cottage, St John’s Wood and Primrose Hill. Typically fitted with higher-specification mechanisms. Gearbox access and replacement follows a similar process to uPVC.
French doors — two-leaf doors have a different multipoint setup with an active and passive leaf. The active leaf has the main gearbox; the passive leaf has a separate shoot bolt mechanism. We repair both.
Patio and sliding doors different from hinged door mechanisms. Often have a hook bolt system rather than a traditional multipoint strip. We carry parts for the most common patio door systems across London.
Aluminium doors commercial and residential aluminium doors have their own multipoint systems, distinct from uPVC mechanisms. We carry aluminium door lock components for the most common profiles.
Composite stable doors top and bottom sections each have independent locking. Gearbox failure on one half affects only that section. Both halves can be repaired independently.
Can Lubrication Fix a Multipoint Gearbox Problem?
In some cases, yes and we will always try the least invasive approach first. Here is the honest answer:
Recent Multipoint Lock Repair Jobs We Have Completed Across London
A resident in Hampstead could not open her front door despite the key turning freely. Broken cam inside the ERA cylinder. Cylinder replaced on the same visit, door opened without any damage to the frame.
French doors in St John’s Wood where the active leaf would not lock. Gearbox on the active leaf had failed. We replaced it with a matching unit, tested both leaves independently and adjusted the passive leaf shoot bolt alignment before leaving.
An older uPVC door in Swiss Cottage with a completely seized Mila multipoint strip. Full mechanism replacement required rather than gearbox only, we advised honestly on this before starting and completed the full replacement on the same visit.
A customer in Belsize Park called expecting a gearbox replacement. On arrival we found the gearbox was working perfectly, the keep plates had shifted and the bolts were missing them. Adjusted the keeps and the door locked correctly. Customer saved the cost of an unnecessary gearbox.
Not sure if we reach your street? Call us on 07468305302 and we will tell you straight away.
Multipoint Lock Repair and Gearbox Replacement Pricing in London
Pricing for multipoint lock repair and gearbox replacement depends on the mechanism type, the brand and whether only the gearbox or the full mechanism requires replacement. You always know the full cost before we start.
Frequently Asked Questions — Multipoint Lock Repair London
Almost certainly yes. When the handle moves freely with no resistance or no bolt movement, the gearbox has failed internally. Call LockFirst and we will carry the most likely replacement on the first visit.
Related Locksmith Services in London
Looking for a related service? These pages cover the full range of lock and security work LockFirst carries out across London:
