Last Updated on March 3, 2023
How to Replace an Existing Door Lock
Replacing a door lock is a simple process that most homeowners can readily handle. This helpful guide will make sure you’ve done it right. If you are looking for directions to fresh install a lock (that is, drill the holes because no lock is already on the door), visit our “How to Install a Deadbolt – Door Preparation for New Lock Installation.”
Replacing a door lock can be reduced to the following steps: buy a new lock that matches your existing lock’s keyway, rekey the new lock to your existing house key, remove the old lock, install the new latch, install the new lock body, check for proper latch operation to ensure your lock is secure.
- Buy a Grade 2 or Grade 1 door locks
- Rekey the locks you’ve bought to match your existing house key
- Make sure your door does not need a lock extension kit
- Remove the old lock
- Replace the lock latch
- Install the new lock body
- Check for proper lock alignment. Do not skip this last step! Improperly installed locks can by bypassed in just a few seconds.
What to Know Before You Change the Door Lock
Most lock products today are built to be affordable, and by that I mean cheap. So, they will eventually stop working and because they are so inexpensive, it is better to just replace the lock than to try and repair it.
In this section I am going to talk about how to replace an existing door knob or deadbolt. If you haven’t yet purchased your new door hardware, take a look at our article on our favorite lock brands and our favorite deadbolts.
Locksmith Tip: What You Should Do Before Replacing the Door Lock.
A detailed article on Things to Determine Prior to Purchasing New Locks can be found at the link. This is a quick overview of that information.
1. Buy replacement locks that are at least a residential grade 2 lock. These locks have anti-bump and pick measures already installed and are more robust than grade 3 locks.
2. Take the locks you bought to your local locksmith so they can rekey them to match your existing house key. This way, you will still have one key for every lock in the house and not be stuck with two keys.For this to work, you need to buy the same lock brand as your existing lock brand or at least buy one with the same keyway (the locksmith in your city can help you find matching hardware). There are two major keyways available. Schlage and Kwikset. The following table shows some common brands that use each keyway.
3. Before changing your existing door locks, measure the width of your door. Locks you will purchase will all be for standard door widths of 1 3/8 to 1 3/4 inch. If your door is thicker than that you will need to purchase a thick door kit for whatever brand of lock you are replacing. Thick door kits contain longer screws and a longer tail peace (for deadbolt) or spindle extension (for door knobs).
4. Note how far away from the edge of the door the lock is. If the center of your lock is 5” away from the edge, you are going to need to buy an elongated latch and bolt. Your local locksmith will carry these, and we encourage you to support your local locksmith. They will make sure you get the right ones for your door locks. But if you want, you can buy them on Amazon as well.
How to Remove Door Locks – Existing Hardware
Removing the old lock is pretty straightforward. You are going to have a couple of screws in the latch plate. These will be Philips-head screws, they will be short screws, and they will come out very easily. If you don’t have any screws on the latch, no worries. That just means your door lock has a “drive-in” latch. We’ll talk about that in a bit.The next step is to find and remove the two interior screws. To remove the door knob screws they will clearly be seen on each side of the knob.
For double cylinder deadbolts (keyholes on both sides of the door) you may not see the screws. Some deadbolts come with a snap-on cover that conceals the internal screws. You will need to pop that cover off to get to the screws and to remove the deadbolt lock from the door. This is common for Schlage deadbolts. A small flathead screwdriver will help you get the cover plate off.These screws can be fairly long as they are holding the lock through the width of the door. Once you loosen each screw it will be quicker to remove them by turning by hand than by the screwdriver.
When removing these screws it is also helpful to each piece of the lock together with your free hand while unscrewing. This will keep the tension off the screws so you can quickly remove them by hand and it prevents the lock from accidentally falling out and damaging any tile that may be installed.
When the screws are out, both sides of the lock will simply slide off, leaving only the latch in the door.
In most cases you can use your fingers in the hole left by the lock to remove the lock’s latch through the side of the door. But sometimes, this may not be possible.
- If your lock is a drive-in latch it will be tight (see latch type photo below). Drive in latches are held in place by compression on a shield around the latch. This type of latch may need to be tapped out with a screwdriver and hammer.
- Or, if the door is old and it is wedged in tightly, you may also need to tap it out with a screwdriver.
This is the time to take note of the door lock’s latch setting. Doors have two common backsets, 2 3/8 and 2 3/4. The new latch needs to be set to the correct one. The existing latch should give you a good idea of which one to use. See if it is in the “short” setting (2 3/8) or the “long” setting (2 3/4).
Installing the Door Locks Into the Door
The installation process is essentially the reverse of removal.
Insert the Locks Latch.
There are three types of latches. Drive-in latches, rounded corner faceplate, and square corner faceplate. If the lock you are changing is the same as the lock you have removed it is unlikely that anything will need to be done, the new latch should go in very easily, but consider these things if it does not.
- Square corner latch going into round corner hole – You will need to chisel out the old rounded corners to install the new square corner latch. Level of skill – easy.
- Round corner into previously square corner – It will fit but there will be gaps at the rounded corners. They pose no security risk if you don’t mind them or you can putty over them with filler if you do. Level of skill – None.
- Square or rounded latch plate into a spot that use to have a drive-in latch – This is the most difficult installation as it will require chiseling out to make room for the new latch plate.I’d recommend replacing existing drive in latches with drive latches to avoid this. But if that is undesired or not possible, you can purchase latch guides. The latch guides will mark for you where you will need to chisel. You hit them with a hammer to cut an impression in the door and then chisel out inside of this impression. Level of skill – Difficult. Here’s our favorite by Kwikset on Amazon.
- Drive-in latch into either of the other two – Also unattractive because of the existing chiseled out space for the old latch, but with the correct lock adjustments, no security risk. Level of skill – None.
- In some cases the new latch plate may be just a bit bigger than the old one and need to be chiseled out to accommodate it. Level of skill – Easy.
Proper Installation of a Drive-in latch.
Drive in latches are meant to fit snugly. The best method for installation is to push the latch in as far as you can and then place a piece of flat wood tight up against the latch. Then tap it with a hammer to finish pushing the latch into the door.
Once your latch is in, I like to install the screws last (after the rest of the lock is installed). It just give me some wiggle room to make sure everything goes together easily.
At this point you want to check to make sure that the center hole in the latch assembly is aligned to the center of the hole in the door. If it is off to the left, or off to the right, the latch will need to be removed and adjusted to the other of its two positions “short” or “long”.
Insert the Body of the New doorknob or Deadbolt
You’re going to want to make sure that you put the lock on the proper side. Obviously we’re going to want to be able to lock the door from the inside and unlock from the outside, so just be cognizant of that when installing a new lock.
Start by putting the exterior side of the door knob or deadbolt into the hole.
- Keyed Locks – When putting in an exterior lock piece with a key hole, be sure that the pins are on the top side of the lock. If it is put in upside down, dust and other debris will quickly fill the pin locations making the lock difficult to use. The lock should be installed so that the cut side of a key, when slid into the hole, is facing up.
- Before changing your lock, be sure to have your local locksmith key your new locks to your existing house key by taking the new locks to the nearest locksmith shop.
The exterior side of your door lock has two rods with threads in them that the interior side will need to line up with for the screws to thread into.
When placing on the interior side of the door visual line up the holes in the knob (or deadbolt) with the receiving rods when placing on the door.
There is also a middle piece. For doorknobs it’s the spindle and for deadbolts it’s the tail piece. If you lined up the screw holes correctly these pieces will naturally align and the two lock sides should slide right together.
It’s now time to tighten the screws. Start by simply threading them in by hand.
They should go easily and you will be able to tell if you have lined up the receiving posts with the screws by doing it this way. Make sure each screw is threading into the receiving posts before tightening all the way.
IMPORTANT – Checking Your Lock-Installation Security
Locks only work when they are installed correctly and when you change a lock there are two very important things you must check for your lock installation to be secure.
Door Latches on Knobs and Handle Sets – Latch Alignment
See that little extra piece of material on that latch? It’s called a deadlocking plunger. Do you know what’s it’s for? Well, it serves to lock the latch in place so it can’t be moved/slid back into the open position by a credit card or screw driver. It is extremely important for your home security to adjust this when installing door knobs.
When the latch is in the out position and the door is closed, the latch should be pushing that plunger into the door. When it pushes the plunger into the door it locks the latch in place so it can’t be forced open (see video below). If the door or strike are misaligned, or if someone has ground out the latch hole too big, the plunger will not be pushed in and the lock with the latch can be very easily bypassed with a credit card or screw driver.
You can view whether or not the plunger is being pushed in correctly by looking through the crack from the inside of the door. If the plunger is not being pushed in, the strike plate (metal plate on the door frame) will need to be moved so that it is.
Watch Me Get Into a Locked Door Where the Latches Aren’t Installed Correctly
IMPORTANT – Check the Deadbolts Bolt for Proper Depth of Hole in Door Frame
If you’ve bought yourself a good deadbolt you’ve bought one with at least a 1” throw. That means the bolt will slide out 1” from the door.
If your old deadbolt did not throw out this far, the hole in the door may not be deep enough for the new deadbolt and it will not secure properly.
When a deadbolt’s bolt does not fully extend outward, it can simply be slid back into the door. Burglars just use a knife or other object to position the bolt back into the door and to bypass it (see video below).
When the deadbolt is fully extended, it cannot be pushed back into the door because it locks in place.
Test the door when open to see where the thumb turn is positioned when the deadbolt latch is fully outward. Then close the door and test again to make sure that the thumb turn is in the same position.
You should be able to either hear or feel when the deadbolt fully extends. If it does not fully extend, you will need to drill out the hole in the door frame a little deeper until the bolt fully extends into it when the door is closed.
Additional Door Reinforcement
There are a number of things you may want to do to your door when changing the locks to reinforce the door and increase the door’s security. Check out our video.
Disclosure: As an eBay / Amazon Associate I may earn from qualifying purchases.
Robert has been the Owner of ACME Locksmith, Arizona’s #1 Rated Locksmith, since 2007. Robert’s company has provided locksmith service to over 160,000 Phoenix houses and businesses.