Window won't lock or open properly, and the handle feels loose or stiff? On a shootbolt window, a gearbox behind the handle drives bolts out of the top and bottom of the sash into keeps on the frame. If the gearbox fails, the window won't lock. We stock replacement uPVC window gearboxes and extension rods from Saracen (including Laird FM, Valiant and Duraflex), Maco (MK1 and MK2), Mila 8 Series, Yale, Nico, ERA and Anglian-style gearboxes.
Match the brand and series, backset and how the rods connect. On many systems the gearbox and extension rods are sold separately.
Look on the gearbox for a name or series, such as Saracen, Maco MK1 or MK2, or Mila 8 Series. Gearboxes and rods must match.
From the face of the faceplate to the centre of the spindle hole. 20mm and 22mm are the most common.
Check how the rods join the gearbox: threaded, twist-fit or clip-on. Replace rods if they are bent or worn.
Some gearboxes have a roller latch that holds the window closed. Check whether yours does.
Open the window fully and remove the handle. Undo the screws along the faceplate on the edge of the sash and disconnect the rods, then ease the gearbox out of its groove. Fit the new lock in the same position, refit the screws and handle, and check it locks smoothly with the window open before you close it.
On many systems, yes. Reuse your rods if they are in good condition, or replace them with matching rods.
Usually. If the handle turns but the bolts don't move, the gearbox has failed. If the bolts move but don't engage, check the keeps.
Browse all uPVC window locks: inline espag, offset flat faceplate, offset U-rail, shootbolt and window keeps.
Not sure which window lock you have? Send us a photo of the faceplate and gearbox 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
