So what's a Replacement Gearbox? Yale Doormaster™ multipoint replacement locks are suitable for most PVCu, composite and timber doors, but sometimes it is possible to carry out a more cost-effective repair. By replacing just the faulty gearbox, the door’s problem is addressed without the added time and expense of replacing the faceplate and locking points. Doormaster™ replacement gearboxes address several common causes of lock failure. Designed especially for the professional installer, the range suits many of the most popular models on the market, including locks from Yale G2000, YS170, Lockmaster, GU, and Mila. You can learn more about our Doormaster™ replacement gearboxes, by reading the product specification or by contacting your local stockist.