The most common faults and what they mean
An accurate diagnosis avoids replacing an entire lock when a single part would have done — or the opposite, piling repairs onto a mechanism that is beyond saving.
- The key turns without engaging
The key bit turns the cylinder but no longer drives the mechanism. Often a broken cam, a snapped pin or a disconnected linkage inside the lock case.
- The key no longer goes in, or refuses to turn
Dirt, corrosion, a seized pin, or a worn key whose profile no longer matches. A poor-quality copy wears out the keyway prematurely.
- The handle is loose or droops
A worn spindle or follower, or a broken return spring. The door may still close, but the latch bolt is no longer operated reliably.
- You have to force it to lock
Almost always an alignment fault: a door that has moved, dropped hinges, a misaligned strike plate. The lock is not to blame, but it wears out quickly under these conditions.
- One point of the multipoint lock no longer engages
A rod linkage out of adjustment or bent, a roller off its axis, a top or bottom strike plate needing repositioning. Keep forcing it and you will end up twisting the gearbox.
Repair or replace?
Repair makes sense when the fault is localised and the part is available: a spring, a cam, a spindle, a roller, a strike plate to realign, a rod linkage to adjust. On a good-quality lock still in production, it is often the most sensible option.
Replacement is unavoidable when the lock case is deformed, when several components fail one after another, when the model is no longer made and no compatible part exists, or when the lock has been through an attempted break-in. A lock that has been attacked must be treated as compromised even if it still works.
One point that is often overlooked: if the door closes badly because of an alignment problem, replacing the lock solves nothing. The door must be adjusted first, otherwise the new lock will suffer exactly the same strain.
What never to do
Never force a key that resists. A flat key twists and snaps off cleanly in the keyway, and the extraction then becomes a job in its own right.
Do not lubricate a lock with a general-purpose penetrating spray or with oil. These products leave a greasy film that traps dust and turns light fouling into a complete blockage. A suitable dry lubricant is what should be used.
Do not remove the faceplate unless you know how to refit it, especially on a shielded multipoint lock: the rod linkage is under tension and refitting it requires precise adjustment.
Maintaining your lock to prevent breakdowns
An annual service is more than enough. A dry lubricant in the keyway, a check that the screws on the faceplate and the strike plates are tight, and a check of the door's clearance within its frame.
In Bordeaux, humid air and temperature swings take their toll on timber joinery: a solid wood front door can swell and press against the strike plate. This is often the cause of premature wear that gets wrongly blamed on the lock.
Above all, watch for the warning signs: having to lift the door to lock it, a key you have to "hunt" for the right position, a locking point that catches. Dealt with early, these symptoms cost no more than an adjustment. Ignored, they end in a lock-up on the doorstep.