Handle lifts but the hooks don't throw, the handle drops, or the key won't turn fully? The gearbox (also called the centre case or lockcase) in the middle of your multipoint lock has usually failed. Replacing just the uPVC door gearbox is often cheaper than a whole new lock. We stock replacement gearboxes from GU, ERA (Saracen Surelock, Laird and Vectis), Mila (Lockmaster), Maco CTS, Fuhr, Fullex, Yale Lockmaster, Millenco, Kenrick, Avantis, Cego, Safeware and Ingenious.
A gearbox must match your existing lock exactly: brand and model, backset, PZ centres and case size. If the strip, hooks or rollers are also worn, replace the complete multipoint door lock.
Look on the gearbox and faceplate for a name or part number, such as GU, ERA Saracen, Mila Lockmaster, Maco CTS or Fuhr 856. Gearboxes are model-specific.
From the edge of the faceplate to the centre of the keyhole. Most gearboxes in our range are 35mm, with 45mm and 30mm also available.
From the centre of the handle spindle to the centre of the keyhole. 92mm is the most common; 62mm and other sizes are available.
Compare the gearbox length, depth and fixing positions, and check whether it has one spindle hole or two (twin spindle).
Before replacing the gearbox, check the door isn't dropped so the hooks are catching the keeps. If the lock only works with the door pushed hard, adjust the hinges or keeps first.
With the door open, remove the handles and cylinder, undo the faceplate screws and slide the complete lock out of the door. Separate the old gearbox from the lock strip, fit the new gearbox in its place and refit the lock. The fixing method varies by model, so follow the instructions on the product listing.
The centre part of a multipoint lock that contains the latch and deadbolt. The handle and key work the gearbox, which drives the hooks or rollers along the strip.
No. The gearbox must match the make and model of your lock strip, as well as the backset and PZ.
If the strip and locking points are sound, a gearbox is the cheaper repair. If they are worn, bent or broken, or no matching gearbox is available, replace the whole lock.
Browse all uPVC door locks: multipoint locks, gearboxes, keeps & latches, sashlocks and garage locks.
Not sure which gearbox you have? Send us photos of the gearbox and faceplate, including any markings, with a tape measure in shot, and we'll match it for you.
Send us a photo to identify your partMonday to Friday, 8:30–12:30 and 13:00–15:30
