How to remove an old deadbolt before fitting a smart lock

A deadbolt is held to a door by two screws. That is the whole design, and it is why most of these jobs are over in five minutes. Undo the two long screws on the inside, lift the lock apart in your hands, undo two short screws on the door edge, and the bolt slides out. The other version of the job takes an hour, because the screws were painted over some years ago, the heads are soft brass, and whoever fitted the lock last drove them home with a cordless drill on the wrong setting.

This is the step that stalls a smart lock installation more often than any other, and it happens before the new hardware is out of the box. Our walkthrough for fitting a smart lock starts from a clear door with an empty bore. Getting the door to that state is what follows.

What is actually holding it on

A standard residential tubular deadbolt is four pieces and four fasteners, with nothing hidden. The exterior half carries the key cylinder and a flat steel tailpiece that reaches through the door. The interior half carries the thumbturn and sits on an escutcheon, the plate or round rose that presses against the door face. Two long machine screws, usually 8-32 and between two and three inches, pass through the interior half and thread into posts on the exterior half, clamping the two together through the 2-1/8 inch cross bore.

The bolt assembly sits in the 1 inch edge bore, held by two short wood screws through the faceplate on the edge of the door. A drive slot in its middle takes the tailpiece, which is how the key or the thumbturn throws the bolt. The strike plate on the jamb is separate hardware on its own two screws.

Nothing is glued, clipped or threaded into the door itself. If a deadbolt will not come off, the reason is one of those four screws, or paint.

The tools that matter here

• A #2 Phillips screwdriver with a sharp, unworn tip. A bit spinning in a drill is the fastest known way to chew a soft brass head.
• A stubby driver or right-angle bit holder, for a lock fitted close to a wall or a storm door frame.
• A utility knife with a fresh blade, for cutting the paint seal around the escutcheon and the faceplate.
• A stiff putty knife, for easing the bolt assembly out of the edge bore, and a screw extractor set if you already know one head is ruined.

A power driver is fine on the two wood screws in the door edge and a poor idea on the long machine screws, which give up their heads at almost no torque.

Taking the lock off in the right order

Work with the door open and the bolt retracted. A thrown bolt fouls the edge bore on the way out and there is no reason to fight it.

1. Retract the bolt, and wedge the door so it cannot swing while both your hands are on the lock.
2. Score the paint line around the interior escutcheon with the utility knife, several light passes rather than one deep cut.
3. Loosen both long screws a few turns each, alternating, instead of driving one all the way out first. The exterior half is under clamp tension and cants sideways in the cross bore if one side lets go completely.
4. Put a hand on the outside cylinder as the last threads release. Otherwise it drops onto the step, which is how tailpieces get bent.
5. Lift the interior half away, then draw the exterior half out of the cross bore. The tailpiece slides free of the bolt assembly as it comes.
6. Undo the two screws in the faceplate and pull the bolt assembly straight out of the door edge. It should move with finger pressure.
7. Take the strike plate off the jamb last, and only if the new lock ships its own, which most do.

When the screws fight back

Almost all the trouble lives in step three, and it comes in three recognizable forms.

Paint has sealed the plate to the door

Ten years of repaints leave a continuous film bridging the escutcheon and the door face. Pull the plate away without cutting that film and it takes a ring of paint with it, on a veneered door a curl of veneer as well. Run the knife round the outside edge until you feel it drop into the joint, and do the same on the faceplate at the door edge, which is why a bolt assembly refuses to move later.

The head is chewed

A wide rubber band laid flat across the head gives a worn driver something to bite on, and is worth thirty seconds before anything drastic. Failing that, try a slightly larger Phillips or a flat blade across whatever ridge is left. If the recess has gone entirely round, a screw extractor is the reliable answer: drill a small pilot into the head at low speed, then run the extractor in reverse. Keep the drill square so the bit does not wander off the screw and into the escutcheon.

The screw turns forever and never backs out

The threaded post on the exterior half is spinning with it. Have someone hold the outside cylinder firmly, or hook a finger under the interior plate and pull it away from the door as you turn, which loads the threads enough for them to grip. If the post has stripped out entirely the two halves come apart in your hands as the screws unwind uselessly, which is a nuisance rather than a problem.

Trim with no screws showing

Some interior halves present a clean rose and nothing obvious to undo. The screws are always there, behind something.

• A snap-on decorative ring over the mounting plate. Look for a small notch on the underside of the rose and ease it off with a flat blade wrapped in tape.
• A set screw, often a small hex, under the thumbturn or on the bottom edge of the rose. Back it out and the cover twists off.
• A one-sided deadbolt with no exterior cylinder. Still two mounting screws, still under the interior cover.
• A retrofit smart unit already clamped over the original thumbturn. That comes off on its own adapter, with the untouched original deadbolt underneath it.

One case is genuinely different. If the lock body is a tall rectangular case buried in the door edge behind a long faceplate, with the cylinder retained by a small set screw in that edge, it is not a tubular deadbolt at all. It is a mortise lock, it comes out as a whole case, and the smart lock options for a mortise door are a different set from the ones a bored door has.

The bolt that will not leave the edge bore

Both faceplate screws are out and the assembly still sits there. The usual causes are paint, a swollen door pinching the housing, corrosion on a lock that has taken weather through a gap in the trim, or a housing hammered into a bore drilled slightly undersize.

Score the paint again, then work the tip of a putty knife under the lip of the faceplate at one end, lever gently, move to the other end and repeat. Alternating walks the housing out square, where levering hard at one corner cocks it in the bore and jams it harder. Once it moves a quarter inch it will usually pull the rest of the way by hand.

If the bolt would not retract in the first place, removal is not really your problem. A bolt binding against a strike or a swollen jamb has the same causes as a motorized deadbolt that stalls halfway, and they will still be waiting for the new lock.

What to look at while the door is bare

The few minutes after the old lock is off are the only time you see the prep clearly. Write the numbers down: the box for the new lock asks for most of them.

• Cross bore diameter. 2-1/8 inch is the modern standard. Older doors turn up at 1-1/2 inch, which no current smart deadbolt fits without enlarging the hole.
• Backset, measured from the edge of the door to the center of the cross bore. It will be 2-3/8 or 2-3/4 inch. Most locks cover both with an adjustable latch, some do not, and the packaging says which.
• Door thickness. 1-3/4 inch is the common exterior figure and 1-3/8 inch the interior one. Thicker than that and you are into a longer screw pack or a manufacturer extension kit.
• The screw holes. Ones wallowed oval by years of a loose lock will not hold the new lock either; slivers of hardwood in wood glue, left to set, give the screws something to bite.
• The witness marks on the door face, which give you the footprint you are replacing. Smart lock trim is usually larger than what came off, but a smaller one leaves an outline of old paint on show.
• The jamb. If the strike screws were biting into three quarters of an inch of trim rather than the framing behind it, this is the moment to run three inch screws into the stud.

If there is no cross bore where you want the new lock, or the one you have is the wrong size, the job changes character. That is cutting a fresh bore in the door, which is irreversible and worth reading about before the hole saw comes out.

Common questions

How do you remove a deadbolt with no screws on it?

There are always screws. Feel around the underside and lower edge of the interior rose for a small set screw or a lever notch, and take the decorative ring off with a taped flat blade. Builder trim and one-sided deadbolts both hide their mounting screws under a snap-on cover.

Do I have to take the old strike plate off too?

Almost always, because the new lock arrives with its own and the two rarely share a screw pattern or a bolt height. Leaving the old plate in place is how a new bolt ends up catching on the lip.

What if I strip a screw completely?

An extractor set is the clean route. The blunt alternative is to drill the head off with a bit a little larger than the shank, which frees the escutcheon; the headless shank then pushes out from the far side or grips easily with pliers.

Will the new lock cover the marks the old one left?

Usually, but check rather than hope. Measure the old escutcheon before ordering and compare it against the dimensions on the new lock’s spec sheet. If the new trim is smaller, plan on touch-up paint, and do that while the door is bare rather than around fitted hardware.

The short version

Two long screws on the inside hold the halves together and two short screws on the door edge hold the bolt, and that is the entire fixing. Cut the paint seal before pulling anything, loosen the long screws a few turns at a time in turn, and keep a hand on the outside cylinder so it does not land on the step. Nearly every stalled removal is a chewed head, a spinning post or paint, and each has a cheap fix that takes minutes. Before the new hardware goes near the door, measure the cross bore, the backset and the door thickness while you can still see them. That is the difference between finishing today and making a second trip to the hardware store.