It may have been tampered with if the plug was rotated substantially.
Key doe not slid easily into door lock.
Not wd 40 may help.
Usually the lock is too dry.
Spray the door key with a graphite based lubricant.
With the door open use a phillips screwdriver to take out the two connecting screws that are located by the doorknob on the inside of the lock.
If your key will only go into the lock partway there may be an obstruction blocking it.
Slide the key in the lock and tap lightly on the.
Repeat heating and inserting the key until the ice has melted.
Then though it may be difficult at first work the key in and out of the lock.
If lubricating the lock did not work and you suspect there is an obstruction you should call a locksmith.
If it is hold the key with a heavy glove and heat it with a match or lighter and then work it gradually into the keyway.
Sometimes pieces in locks fail.
Try to see if you can rotate the plug back to it s proper locked position with something.
If it unlocks easily inside it may be a simple fix.
If the key won t go into the lock ask yourself if the weather is cold enough for the lock to be frozen.
The key is bent and the lock is straight.
In the future keep a lock de icer on hand.
He also does not like wd40 for locks.
Try these simple steps.
Slide the doorknob off the spindle pull out the lock mechanism and remove the latchbolt from its hole in the edge of the door.
The tip of the key is blunt or dull due to abuse.
Lubricating the lock with non destructive oil i e.
Assuming the door lock is hard to unlock with a key because it is dirty or gunked up inside and not damaged your best bet is to use a dry graphite.
Something is stuck inside the lock.
Is it hard to push your key in your door lock.
Once in place turn it so that.
Get the security you want without the headaches by correcting a sticky keyhole tumbler and key.
Stuck pin due to dust or wear.
Remove the two screws that hold the lock faceplate on the edge of the door.
Trying to remove it yourself without the right tools when you can t see what you are doing could damage the lock.