Overview
A lock that feels stiff, gritty or needs two hands to turn is telling you something is wrong. Ignoring it almost always ends in a snapped key or a seized gearbox. The fix is usually a proper clean, lubrication and a hinge adjustment.
Symptoms
- Key needs firm pressure to turn.
- Handle needs a shove upwards to engage the hooks.
- Locking is fine open but stiff when closed.
- Cold mornings are noticeably worse.
Common causes
- Cylinder is dry or contaminated with dust and old oil.
- Door has dropped slightly, so hooks are dragging.
- Gearbox internals wearing - grease has dried out.
- Frame has moved (common on new-build settlement).
When to call a professional
- Lubricant hasn't fixed it after 24 hours.
- You can hear grinding inside the door edge.
- The key has started to bend or you've had to use pliers.
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.