Replacement of the lock cylinder may be necessary in several cases. Most often it is produced when the lock just broke. There is no need to acquire a new one, because it is enough just to change the internal part of the structure. Also replacement of the larva is required when the old lock seems to be unreliable. The process will take from the owner about 15-20 minutes and will not require special knowledge.
In this article, we will explain how to replace the entrance door lock cylinder with your own hands, give detailed instructions, and also demonstrate a video on replacing the larva.
Tool
Make Measurements
In order to replace the inside of the lock, it is not necessary to assemble a whole set of tools and materials. The master will need only three things:
Measurement of the larvae
Necessary tools Before replacing the lock cylinder in the door, it is necessary to establish the thickness of the door, taking into account the insulation layer (if present) and the size of the core of the lock. This is necessary in order to choose a larva of optimal length. Otherwise, it may be too short. Too long larva is also a bad option. 
By itself, replacing the core after buying a new one is one of the simplest operations.
Sometimes it is impossible to remove a larva by the usual method. This happens when the core mechanism is broken or the key is stuck in the lock. Then do not do without a drill. It is necessary to take a drill with a diameter of about 10 mm and just drill out the core. After this operation, remove the larva is not difficult.
Aesthetic qualities
With the key When choosing a new larva, it is important to pay attention not only to its size, but also to its color. It will be better if the visible part coincides in hue with the door fittings. You also need to decide whether the larva will have two holes for the key, or from the inside, the door will lock onto the "turntable". The sequence of work when replacing the lock cylinder in the following video: