Maco uPVC Door Lock Old Style Replacement Gearbox Lock Centre Case 35mm BacksetMaco Old Style Gearbox A replacement centre case for the Maco Old Style multipoint door lock mechanism. If you're having problems with your door lock, the gearbox is almost always the problem and replacing it with a Maco Old Style Gearbox is as simple as removing a few screws. Maco Old Style Door Gearbox Centre Case Single Spindle Information Important measurements: 35mm Backset 92mm PZ Centres This is the mechanism inside the door that is operated by