How to change a door lock (mortice and rim)

What you need

• Phillips and flat screwdrivers (or a driver with PZ2 and PH2 bits)
• Tape measure or callipers
• 20 mm chisel and hammer, in case the mortice needs trimming
• Drill with a 3 mm wood bit to pilot new screw holes
• Pencil and masking tape
• New lock with the same measurements (Tesa, Yale, Lince, Ezcurra, Mottura; at Leroy Merlin, Bricodepot or a hardware shop)
• New cylinder if the lock does not include one
• 4x40 mm wood screws if the originals are stripped
• Graphite lubricant

Step by step

1. 1

   Identify the type of lock

   Open the door and look at the edge. If you see a long metal plate (the faceplate) with the deadbolt and the latch coming out of it, it is a mortice lock: the case sits inside the timber. If the lock is a box screwed to the inner face of the door with the keep on the frame, it is a rim lock, typical of old external doors, storerooms and garages.

2. 2

   Measure the old one before buying

   On a mortice lock measure three things: the backset (from the edge of the faceplate to the centre of the cylinder, usually 50, 60 or 70 mm), the centres (from the centre of the cylinder to the centre of the handle spindle, usually 70 or 85 mm) and the length and width of the faceplate. On a rim lock measure the distance from the centre of the cylinder to the door edge and the handing (right or left). Take a photo of the faceplate with the tape measure on it and bring it to the shop.

3. 3

   Buy the lock with the same measurements

   Changing size means cutting more timber and is rarely worth it. For a flat entrance door, a Tesa 2030 or Lince 5556 mortice lock with an anti-bump cylinder is the standard. For an external rim lock, Ezcurra 700 or Mottura. Check that the faceplate is the same size so it covers the mark left by the old one.

4. 4

   Remove the handles and the cylinder

   With the door open and wedged, remove the screws from the handle roses and take out the spindle. Loosen the faceplate screw that holds the cylinder (it is level with the cylinder), insert the key, turn about 15 degrees until the cam lines up with the body and pull out the cylinder. If the cylinder is fine, you can reuse it.

5. 5

   Take out the old lock

   Mortice: remove the two faceplate screws and pull the case outwards, levering carefully on the faceplate, not on the bolt. If it is painted over, run a craft knife round the outline first. Rim: remove the screws from the case and from the keep on the frame.

6. 6

   Fit the new lock

   Mortice: slide the new case into the mortice. If it is tight, trim with the chisel; do not hammer it in. Screw on the faceplate with the two screws. Rim: offer up the case, mark the holes, pilot drill with the 3 mm bit and screw it on. Check that the bolt goes in and out freely before going on.

7. 7

   Fit the cylinder and handles

   Insert the cylinder with the key in and the cam aligned, screw in the faceplate screw without tightening fully (overdo it and the cylinder goes stiff). Fit the spindle and the handles. Turn the key with the door open: it should move smoothly and the bolt should throw two full turns.

8. 8

   Adjust the keep and test with the door closed

   Close the door and turn the key. If the bolt rubs on the keep, loosen the keep on the frame, move it 1-2 mm and tighten again. If necessary, enlarge the recess with the chisel. Put graphite in the cylinder and keep the builder's keys separate from the final ones.

Lock or cylinder: what you actually need to change

Most people searching for how to change a door lock only need to change the cylinder. The cylinder (bombín) is the part the key goes into. The lock is the case with the deadbolt and the latch. They are independent parts.

If you have lost your keys, moved house or want more protection against bumping, change only the cylinder: 10 minutes and 35-70 euros in materials. We explain it in how to change a lock cylinder and in how to measure a lock cylinder.

Change the complete lock when the bolt will not come out or go in, the key turns freely with the cylinder in good order, the mechanism makes a metallic noise, a rim lock is rusted inside, or you want to go from a single-point lock to a three-point one (only on doors that allow it).

Common mistakes when changing a lock

• Buying without measuring. There are a dozen different backsets and centres. A lock with a 60 mm backset will not go in the hole for a 50 mm one, and one with a shorter faceplate leaves bare timber showing.
• Getting the handing wrong on rim locks. They come right-handed and left-handed. Look at the door from outside: if the hinges are on the right, it is right-handed. Many mortice locks are reversible; rim locks not always.
• Overtightening the cylinder screw. It distorts the cylinder and the key goes stiff. It should be firm, not tightened fully.
• Reusing stripped screws. If the timber is chewed up, use longer screws or fill the hole with a glued wooden plug before screwing.
• Closing the door to test without the key in your hand. It sounds obvious, but every month we open doors for this reason.
• Drilling the old lock because it will not come out. Never drill a reinforced or armoured door: you destroy the escutcheon and the door loses its security rating. If the lock will not come out, there is a screw or a bolt still thrown.

When to call a professional

A mortice lock on an internal timber door or a flat entrance door is a manageable job. A reinforced or armoured door with a three or five-point lock, a security lock with an escutcheon, or an aluminium or PVC door with a multipoint lock is not. Those locks have rods, espagnolettes and adjustments which, if they end up wrong, mean the door will not close or cannot be opened.

At Manitas Costa a complete lock change costs 80-150 euros labour plus the price of the lock, which we show you before fitting it. A cylinder change is 40-60 euros plus the cylinder. Fixed price by WhatsApp, visit the same day or within 24 hours, 6 months written guarantee and an invoice.

See the locksmith in Valencia, Alicante and the Costa Blanca page and the detailed prices in how much a locksmith charges in 2026. We work in Valencia, Alicante, Torrevieja and Benidorm.

• Reinforced, armoured or multipoint-lock door.
• Security lock with an escutcheon or a master-keyed dimple key.
• External aluminium, PVC or metal door.
• The hole in the door does not match any lock on the market.
• You want a smart lock fitted (Nuki, Yale, Tedee) with a guarantee.

Which lock to fit on an external door on the coast

An external door in Torrevieja, Santa Pola or Dénia gets salt and damp all year round. Rim locks with a painted iron case rust inside within a few years and one day the bolt sticks fast. For outdoors you want a stainless steel lock or one with an anti-corrosion finish, and a nickel-plated cylinder.

For the street door of a villa or townhouse, a security rim lock such as Ezcurra or Mottura with an escutcheon, or a three-point mortice lock if the door is new. For a flat entrance, a standard mortice lock with an anti-bump cylinder and a security escutcheon: with 100-150 euros of materials you gain a lot over the builder's lock.

In any case, lubricate with graphite twice a year and check that the door has not dropped. A bolt rubbing on the keep forces you to strain the key and ends up breaking the cylinder. If the door rubs, see door rubbing on the floor or frame.