1 Add lubricant

• If a lock is jammed, do not try to force the key to turn: you could break the key in the lock.

• Apply a few drops of penetrating oil to the key, or dry lubricant, such as graphite powder, to the lock, to ease the problem.

2Work key

• Work the key gently in and out of the lock, adding a little more lubricant if necessary.

• If this fails, either replace the cylinder if it is a cylinder lock( see below) or replace the lock body of a mortise lock( see below).

JAMMED CYLINDER LOCK

• If a cylinder lock is jammed( see above) or if you are worried about the security of your existing lock, replace the cylinder.

• Unscrew the lock body on the internal side of the door, then unscrew the cylinder.

• Remove the cylinder from its cavity by pulling it from the external side of the door.

• Insert a new cylinder by sliding it into the cylinder hole and screwing it into place.

• Put the lock body back in position and refix the holding screws.

Slide the new cylinder into the existing cylinder hole

DAMAGED MORTISE LOCK

• If a striker plate is damaged, causing a door to stick as it closes,

buy a replacement.

• Unscrew the damaged striker plate from its position in the door jamb.

• Insert a replacement striker plate in exactly the same position and

screw it into place.

• If a mortise lock is jammed( see above) or if you are worried about the security of your existing lock, replace the lock body.

• Unscrew the lock body and remove it from its mortise in the door.

• Insert a replacement lock body into the mortise and screw it into place. If the fit is too tight, use a wood chisel to enlarge the recess slightly.