In short:
- When a key turns but the bolt doesn't move, the link between the key and the bolt has usually failed: the cylinder's cam, the cylinder itself, a connecting bar, or the mechanism inside the lock case.
- First rule out the simple things: another lock or bolt still engaged, a key not fully inserted, or a handle that also needs to be turned or lifted.
- Don't keep spinning the key, lever the door or take the lock apart. That can turn a repair into a replacement, or a locked door into damage to the frame.
- A loose, protruding or damaged cylinder can be a sign of attempted forced entry. Treat it as a security problem, not just a fault.
First: are you locked out, locked in, or just stuck with a faulty lock?
The right next step depends on your situation:
- Locked out with no other way in: this is a lockout. See our emergency lockout service, and read the rest of this page while you wait so you can describe the fault clearly.
- Locked in: if there's any risk to anyone's safety, such as fire, a medical problem or someone unwell, contact emergency services first. Lock repairs can wait.
- The door is open, or there's another way in and out: you have time. Leave the faulty lock alone and arrange a lock repair before it fails completely.
Signs of tampering? If the cylinder is loose, sticks out further than it used to, is scratched or bent around the keyhole, or the door or frame shows pry marks, someone may have tried to force the lock. Don't touch it more than you have to, report it to SAPS, and read about lock damage after a break-in.
How a key moves the bolt
Most modern door locks are made of two parts: a cylinder, which recognises the key, and a lock mechanism, which moves the bolt. On a euro-profile cylinder, turning the right key turns a small arm in the middle of the cylinder called the cam. The cam turns inside the lock case and pushes the parts that move the bolt, or on a multipoint lock the gearbox that drives the hooks and bolts along the door edge. A long fixing screw through the edge of the door holds the cylinder in position, so the cam lines up with the mechanism.
Lever mortice locks work differently: the key itself goes into the lock case, lifts a set of levers and pushes the bolt directly. Rim nightlatches use a flat connecting bar (tail bar) that runs from the cylinder on the outside, through the door, into the lock case on the inside. Whatever the design, "the key turns but nothing happens" means one link in that chain isn't passing the movement on.
What the symptom can point to
| What you notice | Possible causes | Safe check |
|---|---|---|
| Key spins all the way round with little or no resistance, and the bolt doesn't move | Broken cam or internal failure in the cylinder; cylinder shifted out of position; broken connecting bar on a nightlatch | Try a spare key. Look at whether the cylinder is loose or sticks out. |
| Key turns part-way, then stops at the same point every time | Bolt or hooks binding on the strike or keeps; worn or broken part in the lock case | Notice whether wind, a door closer or swollen seals are pressing the door against the frame. |
| Key turns and you hear the bolt move, but the door still won't open | The latch is still held: handle not working the latch, a second lock or bolt engaged, or multipoint hooks still caught | Check every other lock, slide bolt and security gate. Turn or lift the handle fully as normal. |
| Spare key works, everyday key doesn't | Worn or damaged key | Use the spare carefully and arrange a check. Keep the worn key to show the technician. |
| It works sometimes and not others | Intermittent failure in the cam, gearbox or connecting bar; alignment that changes with heat or weather | Note when it fails. Don't rely on the lock. |
Some movement is normal on some cylinders. EVVA's documentation describes cylinders with free-wheel cams, used with certain multipoint gear locks, which turn freely until they pick up the mechanism. What matters is a change from how your lock normally feels.
Possible causes by lock type
Euro-profile and oval cylinders (in mortice or multipoint locks)
- A broken cam or broken cylinder internals. The key turns the plug, but the movement no longer reaches the cam.
- A cylinder that has moved. EVVA lists common fitting errors: a fixing screw that misses the hole in the cylinder, or is too short, leaves the cylinder unsecured in the lock. A cylinder that has crept out of position may not line up with the mechanism.
- Damage from an attack. Cylinders can be attacked during attempted forced entry. A cylinder that turns freely and also looks damaged, loose or proud of the door should be treated as a security issue.
Multipoint locks
On a multipoint door, the cylinder drives a gearbox in the lock case, which moves hooks, rollers or bolts along the door edge through a connecting rod. If a part of the gearbox or rod has failed, the key and handle can move while some or all of the locking points stay out. Locking points can also be held under load when the door is pressed hard against its keeps, which makes the key stop part-way. Misaligned keeps add to that load. EVVA tells installers to check, with the door open, that the cylinder and multipoint lock work correctly as a unit.
Lever mortice locks
The key works the bolt directly through the levers, so a key that turns without moving the bolt points to a worn or broken part inside the lock case. On a sashlock (a lock with both a latch and a deadbolt), remember that the key usually only works the deadbolt. If the deadbolt is withdrawn but the door still won't open, the problem may be the handle not drawing back the latch.
Rim nightlatches
The outside cylinder's connecting bar has to reach into the lock case by the right amount. Yale's rim nightlatch instructions, for example, say to cut the bar so it projects 12mm beyond the inside of the door, and other models use different figures. A bar that is too short, has slipped or has broken can leave the key turning without drawing back the latch. Some nightlatches can also be deadlocked from the inside with a key, which stops the inside knob from working. That is a security feature, not a fault.
Sliding-door hook locks
The key or lever turns a mechanism inside the narrow lock case that swings a hook out of a keeper on the frame. If that mechanism has broken, or the hook is caught under load because the door has dropped or moved on its track, the key can turn without releasing the hook.
Safe checks before you call
These checks are about observation, not about getting the door open by other means. Stop if anything feels as though it's about to break.
- Check every other lock. A second deadlock, a slide bolt, a top or bottom bolt, or the security gate in front of the door can all hold a door shut after the main lock is open.
- Make sure the key is fully in. EVVA says to turn the key only once it is pushed in as far as it will go.
- Try a spare key, preferably an original. If the spare works, the everyday key is probably worn or damaged.
- Use the handle as normal. On many sashlocks and multipoint locks you need to turn or lift the handle as well as turning the key.
- Notice the feel: does the key spin freely, stop at a firm point, or turn with a click but no bolt movement? Do you hear anything move inside the door?
- Look at the cylinder without touching it more than necessary. Is it flush with the handle plate, or loose or sticking out? EVVA says its profile cylinders should project no more than 3mm from the outside of the door.
- From the inside, if you're there: does the thumbturn or inside key work when the outside key doesn't? That helps narrow the fault to one side of the cylinder or to the lock mechanism.
What makes it worse
- Spinning the key over and over, harder each time. If something has broken, you're wearing down what's left.
- Using tools on the key for extra turning force. EVVA specifically says not to use screwdrivers, pliers or a bunch of keys.
- Levering, kicking or shouldering the door. This damages the frame, strike and door edge, and a locked bolt can tear out timber.
- Removing the cylinder fixing screw or taking the lock apart. On a locked door this rarely helps, and the cylinder may be holding parts in place.
- Spraying lubricant into a lock that has broken inside. Lubricant doesn't reconnect a broken part. Follow your lock maker's guidance on lubrication only when the lock is working.
- Trying methods from the internet for opening a locked door. They damage locks and doors, and should be left to a professional who can choose a non-destructive approach where the lock allows.
When to call, and what helps the technician
A key that turns without unlocking is not something to live with: next time the door may not open at all, or may not lock. Call a locksmith if the fault has happened even once on an outside door. If you're locked out, our lockout service applies. Otherwise a lock repair visit will find which link has failed. As a mobile locksmith in Sandton, the technician works at your door and will explain whether a part can be replaced or whether the cylinder or lock needs replacing. Our guide to lock repair or replacement explains that choice.
When you get in touch, it helps to send:
- Photos of the lock from both sides, and of the door edge showing the faceplate with any brand name or numbers.
- A short video of what happens when you turn the key, if you can take one safely.
- Whether you are locked out, locked in, or have another way in and out.
- The door type (timber, aluminium, steel, sliding) and whether there's a security gate in front of it.
- Whether a spare key behaves the same, and whether the lock was stiff before it failed. A stiff lock often comes before a failure. See why door locks go stiff.
- Any signs of tampering, and a SAPS case number if you've reported one.
Questions
Is it the key or the lock?
Try a spare key. If the spare works normally, the everyday key is probably worn or damaged. If both keys turn without moving the bolt, the fault is in the cylinder or the lock mechanism. We don't offer key cutting, so if the original key is the problem, keep the spare safe and discuss the options with the technician.
Can the door be opened without damage?
It depends on the lock and on what has failed. A technician will normally try a non-destructive approach first where the lock allows it, and will explain before doing anything that would damage the lock or door.
The lock works again now. Can I ignore it?
It's not worth the risk. An intermittent fault in a cam, gearbox or connecting bar usually gets worse, and it tends to fail completely at an inconvenient moment. Have it checked while the door still opens.
Need a locksmith to look at it?
If this hasn't solved the problem, our lock repairs service covers it. We're a mobile locksmith in Sandton, so we come to your door.
Sources and further reading
- EVVA: lock cylinder installation and operating manual — Cam position, fixing-screw errors, free-wheel cams, checking the cylinder and multipoint lock together, 3mm projection, no tools on the key
- Winkhaus: profile cylinder fitting and care instructions — Cam must move freely; cylinder must not be jammed by the door or fittings; don't force the key
- CISA: cylinder installation guide — Aligning the cam with the cylinder profile; fixing-screw length and over-tightening
- Yale (ASSA ABLOY): rim nightlatch installation instructions — Connecting (tail) bar cut to project 12mm beyond the inside of the door on this model
- Latham's Steel Doors: multipoint lock troubleshooting — The key should turn the cylinder cam smoothly; checking the cylinder separately from the multipoint mechanism
- RACV: how to maintain your locks — Call a locksmith when a lock has been damaged or forced, or stays faulty