Metallic door lock center cases with gearboxes, displayed in a disassembled manner against a white background.
Diagram illustrating how to measure a Mila uPVC door lock centre case gearbox, showing the "Backset" (A) and "PZ" (B) dimensions for correct fitting.
Metallic door lock center cases with gearboxes, displayed in a disassembled manner against a white background.
Diagram illustrating how to measure a Mila uPVC door lock centre case gearbox, showing the "Backset" (A) and "PZ" (B) dimensions for correct fitting.
Lockmaster

Lockmaster Deadbolt Gearbox – Replacement Centre Case for uPVC Multipoint Door Lock – 35mm or 45mm Backset 92mm PZLockmaster Deadbolt Gearbox - 45mm Backset - 92mm PZ

1 review
£35.99 SKU: HS3721
Backset
Lock Operation
Backset
Lock Operation
Order by 2pm for same-day dispatch
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Same-day dispatch on orders before 2pm

The gearbox is the most common part to fail on a Lockmaster multipoint lock — replace just this centre case, not the full strip, and save.Check you backset is 35mm or 45mm before ordering.

Key benefits
  • Direct Lockmaster replacement - hook or deadbolt versions
  • Restores multipoint lock function - saves replacing the full strip
  • Standard Lockmaster dimensions - measure your case before ordering
Product overview

Lockmaster Deadbolt Replacement Gearbox

The Lockmaster deadbolt centre case gearbox is the mechanism inside your uPVC door that is operated by the handle. It is the part most likely to fail when a multipoint door lock stops working.

Replacing just the gearbox is far more cost effective than buying a complete new multipoint lock. The centre case re-attaches to your existing locking strip.

Key Measurements

The most important measurements are 35mm or 45mm Backset and 92mm PZ.

This gearbox is non-handed, fitting both left and right-handed doors. Available in single spindle and twin spindle configurations.
Delivery & Returns

How much is delivery?

UK Mainland Delivery is £2.99 on all items no matter how many you order!

Northern Ireland, Scottish Highlands, Channel Islands £6.00.

We do not offer International Delivery (Ireland, France, Spain etc).

When will my order be dispatched?

Orders before 3pm (Monday to Friday) are usually dispatched same day but may take up to 24 hours.

When will I receive my item?

We ship on 2 working day courier. Fully Tracked. Tracking will be emailed on dispatch. 

Special order items such as keyed alike locks will take longer to dispatch. Please refer to product description for lead times. 

I haven't received my item?

Please email us your name, order number and date of purchase.

We prefer email as it allows us time to research and respond.

Returns Information

We operate a 30 day refunds and return policy. 

If you change your mind you must return the product back to us within 30 days of delivery

Please include a copy of your invoice and a note stating reason for return. 

Additional keys, locks keyed alike or built to code are non refundable as they are personalised made to order goods.

Any refund, which is due to a fault or other defect, will include a refund of the applicable delivery charges otherwise not. 

It is the buyers responsibility to arrange the return of goods to us. We do not offer a collection service for returning items. 

Items must be returned including original product packaging and accessories.

We reserve the right to refuse any returns that do not comply with this policy.

Please post returns to the following address:

Home Secure (Online)

Unit 5, Brookfield Drive

Liverpool, L9 7AJ

United Kingdom

Frequently Asked Questions

The Lockmaster deadbolt gearbox is the core mechanism in a multipoint lock that controls the deadbolt function, providing strong central locking for uPVC and composite doors.

A deadbolt extends straight into the frame, offering solid resistance and reliable locking. Unlike hook locks, it does not latch but instead relies on direct engagement for security.

Common signs include difficulty turning the key, a stiff handle, or the deadbolt not extending fully. These issues often indicate internal wear within the gearbox.

Yes, in many cases you can replace only the centre case gearbox, making it a cost-effective way to restore your door’s locking performance.

A worn gearbox can eventually fail completely, leaving your door difficult to operate or insecure. Learn more in The Silent Door Failure: How a Worn Gearbox Can Lead to Complete Lock Breakdown.