Window Lock Repair

The main window lock types and how they fail

Different window styles use different locking hardware, and the right repair depends on which one you have.

• Crescent (cam) locks on double-hung windows use a curved cam that rotates into a keeper and pulls the two meeting rails together. Most are zinc die-cast, which is why a forced cam snaps instead of bending.
• Sliding window latches use a spring-loaded catch that hooks a keeper in the frame. The spring weakens with age until the latch stops holding.
• Casement locking handles on newer windows drive a multi-point espagnolette bar that throws several locking points along the sash edge at once.
• Vent locks and sash stops are small secondary stops that limit how far a window can open.

What the symptom usually means

The way a lock fails points to the cause.

• The cam spins but never pulls tight: stripped cam teeth, or a keeper that has shifted on loose screws.
• The lock cannot reach the keeper at all: sash misalignment. Settling framing, swollen wood, or a worn sash balance can let the sash ride low, putting the keeper out of reach while the lock itself is fine.
• A casement handle turns partway and stops: a bent point on the multi-point rod, debris in a keep, or a tired crank operator leaving the sash sitting proud of the frame.
• Everything works but feels gritty: corrosion. Window hardware lives with condensation and corrodes faster than door hardware.

Repair the lock, replace it, or adjust the window

Adjustment is the answer when the mechanism is intact and the problem is alignment, loose screws, or dirt. Replacing just the lock makes sense when a cam has snapped, the die-cast body is cracked, or a spring latch has lost its tension. Most surface-mounted window locks attach with two screws, so a like-for-like swap is routine. Multi-point espagnolette mechanisms are identified by backset, rod length, and locking-point spacing, and they can almost always be replaced without replacing the window. Hardware and labor vary by lock type and window material, so an assessment comes before any decision.

What is safe to do yourself

A few steps are safe and genuinely help.

• Tighten the keeper and lock screws. Loose keepers cause a large share of what looks like broken window locks.
• Clean the track and meeting rails, then use a dry PTFE or silicone spray on moving parts. Skip household oil, which gums up with dust, and use powdered graphite for keyed cylinders.
• Photograph the lock, the keeper, and any brand or size stamps before shopping for parts.

Stop before forcing anything. Muscling a seized crescent lock usually snaps its zinc cam, and prying a stuck sash risks the glass and the balance system.

How a locksmith approaches window lock repair

A locksmith starts with alignment, because even a perfect lock cannot latch a sash that sits crooked in its frame. Next comes identifying the hardware from measurements and stamps, then repairing or replacing it like-for-like. The final check matters most: a window lock is only doing its job when it pulls the sash snug against the weatherstripping. If a window lock in your home will not latch, turn, or hold, call (916) 913-5080, describe what you are seeing, and we will confirm whether we can help before any technician is scheduled.

Frequently Asked Questions

Why does my crescent lock spin without pulling the window shut?

Two likely causes. Either the cam or keeper teeth have stripped, which is common with zinc die-cast locks that have been forced, or the sash has dropped so the cam no longer engages the keeper. Check alignment first: with the window closed, the meeting rails should sit level with each other. If they do and the lock still spins freely, the lock is stripped and a like-for-like replacement is the fix.

Are keyed window locks a good idea?

They resist tampering better than a plain latch, but they carry a real trade-off: a keyed lock on a bedroom window can slow an emergency exit while someone hunts for the key. If a window is a required escape route, use a strong non-keyed lock or a vent stop instead, and save keyed locks for windows that are not exit paths. A locksmith can help you decide window by window.

Can the multi-point lock on my casement window be repaired without replacing the window?

Usually, yes. The espagnolette mechanism is a separate component that sits in a channel along the sash edge, identified by backset, rod length, and locking-point spacing. A failed handle or gearbox can be swapped on its own, and a bent locking point can often be corrected or its keep adjusted. The frame and glass stay untouched in almost every case.

Call (916) 913-5080 about window lock repair.