Repairing Door Knobs, Locks & Hardware

Replacing an old cylindrical door knob with a new one is an easy job when you know how.Master Lock

Replacing an old cylindrical door knob with a new one is an easy job when you know how.

Expert advice on how to repair problems with stuck or frozen door locks, keys that don’t work, and latches that don’t latch.

Many door knob and lockset problems can be corrected before they become so serious that the lockset does not work at all. Often, a malfunctioning latch assembly or lock mechanism causes the problem. An improperly functioning latch may be the result of a poorly fitting door. The lock mechanism may not work simply because the lock is dirty or dry and needs to be lubricated with graphite (do not use any type of oil because this will gum-up the works).

For serious lock problems, it is usually best to call a locksmith or to replace the lock entirely. Most interior door knobs are relatively inexpensive to replace; it doesn’t really pay to have these professionally repaired unless they are special. You can buy door knobs online.

Cylindrical Lockset Diagram©Don Vandervort, HomeTips

Cylindrical Lockset Diagram

Exterior latches and locksets, on the other hand, can be very pricey. If you need a pro to fix problems with a high-quality door knob or lockset, removing the hardware and taking it to a locksmith is usually far less expensive than having the come to you.

Door Latch Is Misaligned

If a door latch does not operate smoothly, the latch bolt on the door may not be lined up properly with the strike plate on the doorjamb. Repairs range from making minor latch adjustments to repositioning the door.

If the latch does not catch, close the door slowly to watch how the latch bolt meets the strike plate. The bolt may be positioned above, below, or to one side of the strike plate. (Scars on the strike plate will show where it is misaligned.) It is also possible the door has shrunk and the latch no longer reaches the strike plate. Once you have figured out the problem, try one of the methods shown here.

For less than a 1/8-inch misalignment of the latch bolt and strike plate, file the inside edges of the plate to enlarge the opening.

If the latch does not reach the strike plate, shim out the plate, or add another strike plate. If the latch still will not reach, shim out the door’s hinges. Replace the door with a wider one as a last resort.

For more than a 1/8-inch misalignment, remove the strike plate and extend the mortise higher or lower as necessary. Replace the plate, fill the gap at the top or bottom with wood putty, and refinish.

Doorknob Is Loose

Doorknobs may become loose over time. Methods of tightening them depend upon the type of lockset. You can tighten a simple interior mortise lockset like the one shown at left as follows:

1) Loosen the setscrew on the knob’s shank.

2) Hold the knob on the other side of the door, and turn the loose knob clockwise until it fits snugly. Then tighten the screw until you feel it resting against the flat side of the spindle. The knob should turn freely.

3) If this does not help, remove the knob and check the spindle; if the spindle is worn, it must be replaced. If the whole lockset is worn, it is best to replace it entirely.

Door Lock & Key Problems

Door latches and locks are somewhat complex pieces of hardware with several working parts that can go wrong and cause them to be unworkable or balky. For helpful do-it-yourself repair techniques for fixing common lock and latch problems, please see How to Repair Door Locks.

Door Key Doesn’t Work

If your door key doesn’t work right, the first and most obvious step is to be sure you’re using the right key. Once you get the door open, try the key again. If it works easily, the deadbolt isn’t engaging the strike plate properly. If it doesn’t work any easier, lubricate the lock with graphite. Then spray a little graphite onto the key and try it several times.

If the key turns but doesn’t unlock the lock, disassemble the lock so that you can be sure the cam or tang is properly engaged with the bolt. Replace any broken parts and reassemble the lock.

Is the lock frozen? If the key won’t go into the lock, ask yourself if the weather is cold enough for the lock to be frozen. If it is, you can heat the key and insert it gradually into the keyway. Repeat heating and inserting the key until the ice has melted. Or you can use a lock de-icer, as discussed below under Door Lock Works Slowly.

Is the key new? A new key that won’t go in or work properly may have rough spots that need to be filed off. To find them, hold the key over a candle to blacken it with soot and then turn it very slightly in the lock and remove it. File down any shiny areas where the soot was removed by the rough spots.


Door Lock Works Slowly

Exterior locks can freeze, interior locks get dirty, and small internal parts eventually wear out or break. Before you buy a replacement lock, try some quick remedies:

lock deicerVictor

Aerosol lock de-icer thaws and lubricates a frozen lock.

Put some graphite into the keyhole, either by squeezing it from a tube or dusting it onto a key, and then operate the lock a few times to work the graphite into the mechanism.

Lock de-icers contain alcohol and other lubricants that help to dissolve gummy, dirty deposits. The last resort is to disassemble the lock to see if something has jammed or is broken—you may be able to set it straight or replace the part without buying a whole new lock.


Entire Lock Cylinder Turns

A cylinder turns when the setscrew(s) meant to hold it in place become loose or broken.

Mortise lockset: Remove the faceplate (if there is one) at the door’s edge and locate the one or two cylinder setscrews. They should be in line with the center of the cylinder. Tighten the setscrew(s) by turning clockwise—be sure they engage the slot that runs along the edge of the cylinder (the key slot should be perfectly vertical). Replace the faceplate.

Surface-mounted rim lock: Unscrew and remove the cover, called a “case.” Tighten the cylinder setscrews. Replace the case.


Lock Doesn’t Latch Properly

When a door latch doesn’t click into position, it usually means the latch and the strike plate are out of alignment. Tighten the hinge screws and then try adjusting the strike plate by loosening its screws and shifting it slightly.

fix loose door strike plate©Don Vandervort, HomeTips

If door latch doesn’t align, adjust the position of the strike plate.

When possible, it’s easier to file the slot in the strike plate a little bit so that it will receive the latch. Shifting the strike plate’s position usually involves mortising the jamb, filling part of the old mortise, and so forth. You can also solve misalignment by replacing the strike plate with an adjustable one.

A latch can stick for many reasons, most of which are easily fixed. Check that the hinge screws are tight. If the door is out of alignment, the latch will bind. Also check the knob and lock assembly for loose screws or misalignment. Finally, look closely at the strike on the door jamb—if it’s blocked or out of adjustment, the latch won’t run freely in and out.


Deadbolt Is Stuck

The chances are good that the bolt is having a hard time finding the throat in the strike plate. Be sure the strike plate is secure and in reasonable alignment with the bolt. You can file the edges of the strike plate a little, and even slightly round the edges of the deadbolt’s end. If this doesn’t work, you’ll probably have to remove the strike plate, fill the screw holes with glue and wood matchsticks, reposition it properly, and rescrew it in.


Key Is Broken Off in Lock

needlenose pliers

Use needle-nose or long-nose pliers to extract a broken key.

Using pliers, try to grip and pull the key straight out. If you can’t get a grip even with needle-nose pliers, cut off a coping saw blade and, with the teeth pointed outward, insert the blade into the keyway and try to hook and drag the key out. As a last resort, remove the cylinder. Insert a stiff wire into the cam slot at the back of the cylinder and push the key out. Or take the cylinder to a locksmith.

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Join the Conversation

  • Tyler Jensen

    I have a thumb-press handle on an exterior door, and the round faceplate keeps slipping out a few mm’s, so the latchbolt won’t retract out of the strikeplate when attempting to open from the outside. Should I just try to superglue the faceplate casing or what’s the best thing to do here?

  • I have a key that work sometimes and not other times. I suspect it does not work properly when it is cold.
    My partner has some way of using it “shuggle it in gradually”. I can’t do it…Could it really be the cold?

    • Don Vandervort, HomeTips

      Yes, it could be the cold. A locksmith would probably be able to refine your key a little bit so it works better. But first, work some graphite into the lock and use the key a few times. This often does the trick.

  • Dede

    The door latch on the front door retracts when you open it but isn’t fully re-extending when you close/turn the knob so it isn’t catching. The information above talks about using graphite to clean it. Would this be a possible solution and, if so, how do I work it into the latch area?

  • Kazzy Wazzy

    Do the Round Internal Locking Knob & Latch systems you buy in a hardware shop use the same keys or are they all different? My friend has the same product and insists his key will work in my lock!

    • Don Vandervort, HomeTips

      The chance of him having the right key for your lock is pretty remote—many, many variations are made.

  • Jack Smith

    Repairing the door knobs is not an easy thing.Its very hard to repair it because little little things need to repair and replace which hasn’t done by yourself so it’s better to hire an emergency locksmith to do that very task.

  • Helen Beseda

    I have a really old hollow metal front door – I replaced the door knob, and in the process, some of the “filling”? – i.e. whatever is in side the metal next to the knob – fell apart. Now, the screws that hold on the latch plate don’t seem to have anything to grab hold of, so they won’t hold. What can I put in there to give the screws something to bind to? Or do I need a whole new door?

  • Karen

    I have a front door lock with the cylinder stuck extended into the door jamb and trying to get the whole door lock off to replace with a new one. How can I get the cylinder to retract so I can take the lock off completely? Have undone the knob and tried retracting from the inside – with no luck. Have tried using small flat screwdrivers in between latch plate and jamb but can only get it to retract a little bit. Have also used graphite. Any help would be appreciated since I can’t use this door at all at present. Thx. ?

  • Mariam

    The door’s lock to my room works on one side only. It is new and gives me a hard time when I open it. When I try locking from the inside, it wont move but from the outside it is ok. How do I fix this?

  • Joel

    I have a new cylinder lock that came with keys, the key easily goes into the lock both right side up and upside down, neither way allows the key to turn in the lock. This lock has been in a warehouse protected from weather but the warehouse is not heated. This lock is factory new, can’t imagine the locks being shipped wrong. Graphite? Lithium grease? what should I try?

  • Don Vandervort, HomeTips

    I’m having a hard time picturing this. Are there any screws holding that ring…or anything else left to easily remove? Can you pry out the ring with an old chisel? Can you remove the interior knob and pry outward from the main hole? Sorry I can’t be more helpful.

  • If you don’t have graphite, a little WD40 can help loosen a stiff lock.

  • helluva66

    I understand exactly what you mean as I have the same problem. What eventually did you do to remove it? Any tips are really appreciated. Thanks!

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