A metal door lock mechanism, typically used in centre case applications for multipoint door locks, displayed 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.
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A metal door lock mechanism, typically used in centre case applications for multipoint door locks, displayed 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 Hook Gearbox – Replacement Centre Case for uPVC Multipoint Door Lock – 35mm Backset 92mm PZ

LockmasterSKU: HS3720
162 reviews from verified buyers
Price:
£49.99

Save £15.00 — limited stock at this price

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

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Description

Lockmaster Hook Replacement Gearbox

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

Replacing the centre case is far more cost effective than buying a complete new multipoint lock. It re-attaches to your existing locking strip, saving you time and money.

Key Measurements

The most important measurements to check before ordering are 35mm Backset and 92/62mm PZ.

This gearbox is non-handed, fitting both left and right-handed doors. It supports single spindle or split spindle operation.

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Frequently Asked Questions

The Lockmaster hook gearbox is the central mechanism in a multipoint locking system, designed to operate hook-style locking points that secure the door firmly into the frame.

Hook locks use curved locking bolts that latch into the frame, providing stronger resistance against forced entry compared to standard deadbolts.

Common signs include a stiff or loose handle, difficulty lifting the handle, or the hooks not engaging properly. These issues usually indicate internal wear.

Yes, in many cases the centre case gearbox can be replaced independently, making it a more cost-effective repair option.

Regular checks help prevent sudden lock failure, which can leave your door stuck or insecure. Learn more in Check This Before Your Next Let-In: Is the Door Gearbox Still Fit for Purpose.