Care & Feeding of Most Common Locks

The most common problem with locks is a dirty mechanism.  Most quality locks are made of brass parts and actually do not require lubricant.  Although a locksmith might be required to clean a lock in bad condition, a novice homeowner can clean his own locks easily with materials available from any hardware store or home center:  safety glasses, a rag, WD-40, compressed air (Dust-Off), and powdered graphite (preferably in an applicator tube with a thin snout or needle).

This can get messy so keep the rag below and around the lock as best you can while performing these steps to avoid splatter and drip and wear eye protection.  You will need the key that fits the lock to move the parts during this process.

Step One:  The WD-40

This is a solvent, not a lubricant.  Flush the lock by spraying it into the keyway generously.  Work the key in and out of the lock and turn it left and right when the key is inserted properly.  Repeat this step several times or until you feel the lock is clean.

Step Two:  The Dust-Off

Flush the lock with air in the same way you did with the solvent.  The idea is to dry out the lock mechanism.  The lock is dry when you can insert and remove the key and all the key’s surfaces are dry.

Step Three:  The Graphite

Locksmiths have better lubricants available to them but graphite works very well for most lock mechanisms.  Spray graphite directly into the keyway and work it in by inserting and removing the key as well as turning it left and right when inserted.  You should feel immediate improvement in the action of the lock.  Feel free to spray the graphite into other seams as well, the more you can reach, the better.

Door Jams:  A common mistake during install is not to install the strike-pocket into the door jamb and instead allow the strike to sit in a bare wood hole when the door is closed.  Inspect this hole and make sure the strike has plenty of room and no wood chips are blocking it.

Dead Latches:  A dead latch is a ramped latch that will push in on it’s own to allow a door to close completely but has a small, secondary latch behind it that prevents a credit-card or similar device from opening the latch.  The secondary latch should not fall into the strike-pocket, if it does, it cannot function properly.  The dead-latch only works when the secondary latch stays pushed into the door and does not fall into the strike-pocket on the door jam.

Dead Bolts:  A dead bolt should extend fully into the strike pocket every time.  Most dead bolts have an extra “click” as the bolt is fully deployed - this is a feature to prevent the bolt from being pushed back into the lock by some form of manipulation.  You can test this by comparing how the lock mechanism works when the door is open and when it is closed. 

Hinges:  Inspect the hinges - if they are worn (many modern doors are too heavy for the hinges used) the door may no longer be hanging properly and the strike(s) are not lined up with their pockets.

Keys: Locks are designed with pins made from better metal than the key so that the key will wear out first - a worn key can damage a lock over time when forced.  If you have more than one key and one doesn’t work the lock very well, take the better key to a locksmith and ask for a “code cut key” based on it.  Test it before making duplicates of it and destroy the worn keys.