Quick answer
If the handle lifts fully and the hooks engage but the key won't lock afterwards, the cylinder cam isn't reaching the gearbox pawl. Usual causes are a sheared cam, a loose or missing cylinder retaining screw, or the wrong-length cylinder fitted previously. It's typically a 30-45 minute fix when caught early.
Overview
This exact symptom - handle lifts fully but the key refuses to turn afterwards - nearly always means the cylinder cam isn't engaging the gearbox pawl. It's a 30-minute fix if caught early.
Symptoms
- Handle lifts smoothly and hooks extend.
- Key turns freely but nothing locks.
- OR key won't turn at all after the handle is up.
Common causes
- Cylinder cam sheared or worn.
- Gearbox pawl has failed to reset.
- Cylinder wrong length - cam not reaching the gearbox.
- Screw holding the cylinder loose or missing.
Why this specific symptom points so precisely at one area
This is one of the more diagnosable lock complaints we hear, because the fault pattern is so specific: the mechanical side of the lock (the handle, hooks and gearbox drive) is clearly working, since the hooks extend properly. The failure sits entirely at the interface between the cylinder and the gearbox — the small cam on the back of the cylinder that engages the gearbox's pawl to hold everything in the locked position.
Because the handle-driven part of the system is healthy, this fault rarely requires a full mechanism replacement. In the majority of cases it's isolated to the cylinder itself or the single screw holding it in place.
The cam-to-pawl handshake, explained simply
Think of the cylinder cam as a small lever that, when you turn the key, reaches across and pushes a corresponding lever (the pawl) inside the gearbox. If that handshake doesn't happen — because the cam has sheared off, worn down, or simply isn't reaching far enough — the key will turn (sometimes very freely, with no resistance at all) but nothing downstream happens.
A key turning with unusually little resistance, especially if it previously took normal effort, is actually a useful diagnostic clue in itself: it often means the cam is spinning without engaging anything, rather than fighting a stuck mechanism.
The most overlooked cause: cylinder length
Euro cylinders come in a wide range of lengths either side of the central fixing screw, and if a cylinder was replaced previously by someone using an approximate rather than measured length, the cam can sit just short of properly reaching the gearbox pawl — working fine most of the time but failing intermittently as tolerances shift slightly with temperature.
This is a surprisingly common finding when we're called to a 'door won't lock after handle lifts' job on a door where the cylinder was replaced within the last year or two, particularly if the previous work wasn't measured precisely to the door's specific dimensions.
- Sheared or worn cylinder cam — most frequent cause
- Gearbox pawl has failed to reset properly
- Cylinder is the wrong length for the door thickness
- Retaining screw beneath the gearbox is loose or missing entirely
The retaining screw — small part, big consequence
A single screw, usually accessed on the door edge just below the gearbox faceplate, holds the cylinder firmly in position against the gearbox. If this screw works loose over time through normal door vibration, the cylinder can rotate slightly out of true alignment with the pawl, producing exactly this symptom of a handle that locks but a key that doesn't.
Checking this screw is one of the first things worth doing, since a loose screw re-tightened correctly can resolve the fault in minutes with no parts required at all — though confirming the fixing is straightforward is best left to whoever attends, given how central this component is to the door's overall security.
Security exposure while this fault exists
This is genuinely one of the more serious-sounding faults in terms of impact, because a door where the handle lifts but the key won't lock leaves the door secured only by whatever the handle mechanism itself holds — typically just a sprung latch, not the deadlocking points a multi-point system is designed to provide.
Until it's repaired, we'd suggest supplementing security with a temporary door chain, a portable security bar, or simply avoiding leaving the property unoccupied. This is not a fault to leave over a long weekend away.
What the repair visit involves
The fix starts with removing and carefully re-seating the cylinder to rule out a loose screw or minor misalignment, testing the lock cycle both open and closed. If reseating doesn't resolve it, the cylinder is measured precisely and replaced with a correctly sized unit, since guessing at length is exactly what may have caused the problem in the first place.
Only if the gearbox pawl itself is confirmed as the fault — rare in isolation, but possible — would a full mechanism replacement be needed, and this would be explained and quoted separately before any work proceeds.
What this specific symptom tells us before we arrive
A handle that lifts freely but doesn't engage the lock is a distinctive fault pattern, and it almost always means the connection between the handle spindle and the gearbox has failed, rather than anything being wrong with the hooks or keeps themselves. Free, effortless movement with no resistance at all is the giveaway — a healthy mechanism always has some spring resistance as the hooks extend.
This lets us bring the correct part with reasonable confidence before we've even seen the door, since it narrows the likely fault down to a snapped or worn spindle, a disconnected follower, or an internal gearbox cam that's sheared clean rather than just worn.
How this fault develops from first appearing
This often starts as a handle that feels slightly 'looser' than it used to, with a bit of play before it engages anything. That looseness is the early sign of a spindle or follower wearing at its connection point, and it typically progresses over a few weeks to the handle lifting with no engagement at all.
Once it reaches full disconnection, the door usually can still be secured by the sprung latch alone, which unfortunately means many people don't realise how insecure the door has actually become, since it still appears to 'shut properly'.
Security risk specific to this fault
This is one of the more deceptive faults we deal with, because the door still closes and the handle still moves normally — there's no obvious visual sign anything is wrong. In reality the door may only be held by the latch, which offers essentially no resistance to anyone leaning on it or using basic force.
We'd treat this as a same-week priority repair even where the customer isn't especially concerned, precisely because the outward appearance of the door gives no indication of how compromised the security actually is.
What we check before quoting
We check the spindle length and profile (these vary between manufacturers and even between models from the same brand), the handle backplate fixing, and whether the gearbox follower itself is damaged or just disconnected. A disconnected but undamaged follower is a much cheaper fix than a genuinely broken gearbox internal.
We'll also check whether the handle has been over-tightened or incorrectly fitted at some point, since incorrect spindle length is a surprisingly common cause of this exact fault on doors that have had handles replaced or swapped previously.
What to tell us when you call
Mention whether the handle feels looser than it used to, whether you can wiggle it side to side more than before, and roughly when the lifting-but-not-locking behaviour started. If the handle was replaced or the door serviced recently by anyone else, tell us — it's often directly relevant to what's failed.
Typical repair costs in Cornwall
| Work | Typical price | Notes |
|---|---|---|
| Cylinder reseat and screw check | £45-£75 | Resolves the fault in many cases with no parts needed |
| Correctly measured cylinder replacement | £65-£130 | Where the existing cylinder is wrong length or worn |
| Gearbox pawl repair/replacement | £180-£320 | Only if the gearbox itself, not the cylinder, is at fault |
| Emergency visit if door won't secure at all | +£40-£60 | Same-day priority booking |
Guide prices only — we confirm the cost after seeing the door.
When to call a professional
- Cylinder screw is missing.
- Reseating hasn't fixed it.
Prevention
- Lubricate the cylinder twice a year with a graphite or PTFE lock spray - never WD-40 or oil.
- Grease the hooks and rollers on the door edge every 6 months.
- Always lift the handle to engage the multi-point locks before turning the key - this takes load off the gearbox.
- Never force a stiff key - book a service call before the mechanism snaps.
