How to replace a door lock

1. Determine the type of lock

For replacement without alterations, you need a lock of the same type as was installed. Now two types are relevant and the most common: cylinder and lever. By the appearance of the key and keyhole, it is easy to determine which locking mechanism is used in the door.

Cylinder

These locks have a round core with a thin and narrow key slot. The key is small, flat, with small notches or dots on the edge or on the upper and lower plane.

Locking is done with spring-loaded pins and a rotating core that locks when the key is removed. When the key is inserted, the rods rise to the desired height and hide in the larva's body, allowing it to rotate freely and open the lock.

Thanks to the design with a removable security mechanism, the cylinder locks can not be completely changed. It is enough to install a new core and the old keys will no longer work. The larvae are standard sizes and are compatible with all cylinder locks.

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A lever lock is easily recognizable by a wider keyhole that you can even look into. Keys - with a long round stem and a square plate with slots at the end.

Secrecy is ensured by a set of levers with special grooves that block the mechanism when the key is not in the well. If the slots on the inserted key coincide with the levers, then during rotation the locking bolt moves and the lock opens.

Unlike cylinder locks in lever locks, the secrecy mechanism is not removable, so they will have to be changed completely. Exceptions are expensive options with a conversion function, which allow you to rebuild the location of the levers for a new set of keys.

2. Measure the dimensions of the lock

To do without adjusting the seat to the case, you need to buy a lock, the dimensions of which are identical to the old one or are as close to them as possible. Otherwise, the mechanism will not fit into the door or the holes in it will not coincide with the location of the well and other elements.

Replacing door locks: measuring dimensions

Here are the most important parameters to look out for:

A - the depth of the entry of the crossbars into the door frame;
B - distance from the center of the well to the mounting plate;
B - the width of the crossbars from top to bottom;
Г - thickness of the mounting plate (lock);
D - diameter of the locking crossbars;
E is the height of the mounting plate.

Ideally, it is best to lock the door with a second lock or ask someone to guard the apartment, and then dismantle the old mechanism yourself and take it with you to the store. So you will find a new one with exactly the same parameters.

3. Buy a new lock

Go to a hardware store or a specialty store and buy a good lock that exactly matches the size of the old one.

If this is not the case, you can take the closest one in terms of parameters, but be prepared for the fact that you will have to expand the landing hole in the door leaf and the groove for the crossbars in the door frame.

Just in case, check in advance whether it is possible to exchange or return an item if it does not fit.

4. Remove the old lock

If there are two locks in the door, then, depending on the location, they are removed in different ways. The upper one is pulled out very easily, but the lower one, which has a handle, is a little more difficult to dismantle.

Cylinder locks are most often used as lower ones, and lever locks are located at the top and serve as additional ones. It can rarely be the other way around.

Cylinder lock

How to remove the core

Open the door and locate the fixing screw on the mounting plate. It is located at the level of the keyhole under the crossbars.
Use a Phillips screwdriver to completely remove the screw holding the cylinder. After that, it will move in the mounting hole.
Insert the key or use the handle from the inside and turn the cylinder 15–20 degrees so that the rotary cam is hidden in the body.
Pull out the core by turning the wrench or handle slightly from side to side if necessary.

How to remove the top lock

Remove the larva as described above.
If the lock is locked from the inside using the handle, then remove it by unscrewing the fastening screws with a Phillips screwdriver.
With the same tool, remove the remaining screws from the end of the mechanism.
Pry the mounting plate with a thin slotted screwdriver and remove the lock from the door.

How to remove the bottom lock

Remove the larva as described above.
Using a complete hexagon, loosen the fastening from the bottom of the handle on the outside of the door.
Remove the decorative rosette (metal ring) from the inner handle. To do this, unscrew the element by hand in a counterclockwise direction.
Use a Phillips screwdriver to unscrew the handle flange fixing screws that were hidden under the socket.
Gently pull the handle towards you along with the square bar.
Unscrew the tightening screws on the keyhole cover and remove the protection.
Use a Phillips screwdriver to remove all screws on the mounting plate. Pry the latter and remove the lock case.

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How to remove the top lock

Use a Phillips screwdriver to unscrew all the fastening screws on the lock mounting plate from the end of the door.
Pry up the housing of the mechanism and remove it from the door leaf.

How to remove the bottom lock

Using a complete hexagon, loosen the fastening from the bottom of the handle on the outside of the door.
Unscrew the decorative ring on the inside of the handle.
Use a Phillips screwdriver to remove all fixing screws on the inner handle flange.
Pull out the handle together with the square.
Remove all screws from the mechanism mounting plate.
Pry up the lock case and remove it from the slot in the door.

5. Install a new lock

First, try it on in the old place. If the lock fits completely into the door, and all the fastening holes and grooves for the crossbars are the same - just install the new mechanism in the reverse order of removal.

If the mounting size does not match, you will have to adjust the mounting holes and grooves. On a wooden door, this is done with a chisel, on a metal door - with a file. Keep in mind that the lock should not be loose after fitting. If the discrepancy is large, it may make sense to return to the store and find a more suitable model.

Cylinder lock

How to install the core

Turn the rotary cam of the larva with a wrench or a handle so that it is hidden in the body.
Insert the core into the mechanism. Make sure that the hole in the cylinder body aligns with the hole in the mounting plate.
Tighten the core fixing screw first by hand and then with a Phillips screwdriver.

How to install the top lock

Insert the lock case into place and secure with the screws on the mounting plate. Screw them on the thread, first by hand, and then with a screwdriver.
Place the cylinder in the housing and fix it with the fixing screw.

How to install the bottom lock

Place the lock mechanism on the door leaf. Tighten the mounting plate screws by hand, then tighten with a Phillips screwdriver.
Install the keyhole covers and tighten with the screws.
Insert the handle together with the square rod into place. Tighten the handle flange fixing screws. Screw the decorative rosette on it clockwise.
Use a hexagon to secure the fasteners underneath the outer handle.
Insert the core into the housing and secure it with the screw from the side of the mounting plate.

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How to install the top lock

Place the lock mechanism in the space provided.
Tighten all the fixing screws on the mounting plate.

How to install the bottom lock

Insert the lock body into the slot in the door.
Tighten the screws for the mounting plate by hand and then with a screwdriver.
Place the inner handle together with the square bar in place.
Install the handle flange screws and slide the decorative ring on top by turning it clockwise.
Fix the fasteners underneath the outer handle with the hexagon.