Why a Door Lock Freezes
House locks, on the average have five pairs
of pins, located within a cylinder, that need
to move freely to engage recesses that lock
the door. The cylinder that these pins fit into
must also be allowed to rotate freely. When
the key is inserted into the cylinder, the
different shapes cut into the key line up with
the pins that push them into place. When
the key is inserted and turned the cylinder
rotates and locks or unlocks the door.
When the outside temperature plunge to
minus 20 to 30 degrees F, any moisture
within the door lock mechanism may freeze
the door lock metal parts solidly together,
especially in windy conditions, where the
chill factor is even lower.
The house door locks that freeze, are the
ones located in rooms cooler that normal
room temperature, such as where a garage
door connectsd to a house. The garage is not
heated as well as inside the house, the lock
mechanism within the door may not stay
warm, which allows the lock mechanism to
The moisture in the warmer air in the garage
tries to escape to the outside along the edge
of the door, and inside the lock enclosure
itself, passing the lock assembly parts.
When this moisture contacts the cold metal
of the lock, it freezes. The moisture content
in the air at 30% will freeze a lock at about
-35F, as the moisture content in the home
raises, it takes less cold to freeze the lock.
Older lock assemblies that have been
lubricated at one time, attract dust and grim
over time, the oil and grime dry out, this
causes the lock assembly to become
sluggish, which adds to the problem.
When moisture is added, the water particles
attach to the grime and metal and freeze
the lock mechanism.
Frozen Door Bolt Mechanism
Fixing a Frozen Door Lock
To fix this problem the door lock mechanism
must be removed from the door and all oil
and grime must be removed from the sliding
and turning parts. Use a Philips screwdriver
to remove the two long bolts (2 inches)
which hold the knob turning assembly
together, and the two short screws
(3/4 inch) that hold the bolt sliding
mechanism to the door.
Turning anti-counterclockwise removes.
Slide out the bolt assembly. Wash all the
lock mechanisms thoroughly with Varsol and
a paint brush. Place the sliding bolt assembly
into a container like a used metal coffee
container, add Varsol, place the lid on and
shake thoroughly. Dry off all the lock
mechanisms with a cloth and finish drying
with an electric hair dryer or heat gun.
Do not get too close; just close enough to
heat the metal to vaporize the Varsol.
When finished the metal should have a very
dry look. If the knob assembly is sluggish,
also clean it well with Varsol.
Lubricating a House Lock Mechanism
A couple of products recommended to
lubricate the lock mechanisms are Move-it,
WD40, and Lloyds MooVit high performance
penetrating lubricant. Lubrication is needed
to displace moisture and provide lubrication
to the turning, and sliding mechanisms.
Lightly spray all the moving parts.
Assembling the Lock Assembly
Install the sliding bolt assembly into the door.
The beveled edge points towards the hole in
the door jam. Secure in place with the two
short screws. Clockwise tightens. Slide the
door knob assembly into place, with the
keyed side facing the outside, and the
manual locking inside. Secure together with
the two long bolts (2 inches). Start the bolts
with finger pressure to prevent cross
threading. Center the door knob assembly
on the hole in the door and tighten.
For the very difficult frozen lock, carry a
small butane cigarette lighter, heat the key,
the heated key will warm the inside of the
lock, and unfreeze the lockmechanism
momentarily, allowing you to enter the home.
This action will also work for frozen car
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