Why locks get sticky
- Dust and grit. The keyway is open to the weather. In Santa Clarita, with dry, dusty summers and Santa Ana winds, fine dust packs into the cylinder over the years.
- A worn key. A copy of a copy, or a key carried for a decade, no longer lifts the parts inside cleanly. The lock is often fine.
- The door, not the lock. If the lock turns easily with the door open and fights only when the door is shut, the bolt is rubbing the strike plate. See deadbolt will not lock.
- Wear inside the lock. On a lock that has seen many years of use, the parts themselves wear.
Why not WD-40
WD-40 and other oily sprays seem to work for a week. They are mostly solvent, they wash out what little dry lubricant was there, and the oil they leave behind catches dust. A month later the lock is stiffer than before, now with a paste inside. Use them on hinges, not inside locks.
What to use instead
Use a dry lubricant made for locks: powdered graphite or a dry PTFE lock spray. A short puff into the keyway, then work the key in and out and turn it several times. Wipe the key. Once or twice a year is plenty for most front doors.
Test with a fresh key cut from the original key, not from a copy. If the new key turns smoothly, the old key was the problem; our key duplication page explains why copies of copies drift.
When it is a locksmith job
If a dry lubricant and a good key do not help, or the key has started catching on the way out, the cylinder needs cleaning, repair or replacing before it fails. A rekey replaces the worn parts inside and gives you new keys at the same time; a lock change is for a lock that is worn out or damaged. Do not wait for the key to snap: a broken key in the lock is a bigger job, see key broke in the lock.
Questions people ask
Should I use WD-40 on a sticky lock?
No. It is mostly solvent, and the oil it leaves collects dust, so the lock gets stiffer within weeks. Use powdered graphite or a dry PTFE lock spray instead.
How often should I lubricate my door lock?
Once or twice a year for most front doors, more often on a door facing the weather or a dusty street.
Is it the key or the lock?
Try a fresh key cut from the original. If it turns smoothly, the old key was worn. If not, the lock needs attention.
Will a rekey fix a sticky lock?
Often, yes. A rekey replaces the worn parts inside the cylinder and gives you new keys.