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How to Replace a Mailbox Lock? – The Easiest Way

Fact checked by Teddy B.Miller

how to replace a mailbox lock

Wondering how to replace a mailbox lock? Open the mailbox by drilling the keyhole. Remove the nut and slide the lock bar and the metal clip. Pull out the old lock and install the new one. Place the new lock and tighten a nut at its end. Once done, check if the lock is working properly.

If you lost the key to your mailbox or it is already dysfunctional, there is an easy way to change a mailbox lock. You can do this tutorial in only five minutes, depending on how good you are at following instructions.

What You Need


Replacing mailbox lock may be challenging if you don’t have the right tools to help you out. Before you start with the tutorial, prepare the items required to prevent any inconvenience in the future.

Replacement lock

For mailbox lock replacement, the new lock must have the same size as the old one. If the lock is too small for your mailbox, it won’t lock and it can be easily pulled out of the mounting hole. If it’s too big, your key would get stuck once you try to lock it. It’s advisable to check the size of your old lock before purchasing a new one.

Make sure that the mailbox lock is made of tough materials like steel and nickel. Also, it is better if you would purchase a lockset where the nut and keys are already included so you don’t have to buy them separately.


Nuts have different shapes and sizes. The wrench that you will use depends on the size of the nuts that the mailbox lock has. The sizes of nuts range from 2 mm to 20 mm while the size of the wrench ranges from 4 mm to 30 mm.

For this tutorial, an adjustable wrench is handy. It is the most common type of wrench. Compared to some wrenches, this one has an open end and a flexible jaw.

Drill and drill bit (optional)

If you own the mailbox then you are free to drill it. But if it is owned by USPS, don’t drill the mailbox lock since it is illegal. You can use a cordless drill for your mailbox since it would provide you with mobility. It would also save you from using an extension wire, especially if your mailbox is far from your house.

For the drill bit, you can use titanium or cobalt since you will be dealing with metal. You can use a smaller size bit to prevent damaging the housing of the lock. Your goal is to open the mailbox lock and not to create a hole in it.

What to Do


Step 1: Open the mailbox by drilling the keyhole

If you cannot open the mailbox because you lost your key, you can drill the keyhole of the lock to open it. Avoid putting too much pressure on the lock since you may damage its housing. However, if you are using a USPS cluster mailbox, never attempt to drill it. You can wait for the postmaster and request him to open it for you.

Read more: The easiest way to pick a mailbox lock.

Step 2: Remove the nut and slide the lock bar and metal clip

Before you can take off the lock, you need to remove the nut and the pin. You can just slide the lock bar and metal clip that hold the locking mechanism. For the nut, you will need to use a wrench in order to remove it. However, if you are lucky enough, drilling could disengage all of them.

Step 3: Pull out the old lock and install the new one

Now, pull out the old lock and install a new one on the spot where the old lock used to be located. The latch must be in a vertical position. Once done, use an adjustable wrench to tighten a nut at the end of the lock. This will secure the lock in place. After that, check if the lock is working properly.

Frequently Asked Questions

How much will it cost me if I pay a locksmith to replace my mailbox lock?

The average cost for changing the mailbox lock ranges from $30 to $60. However, if you live in an apartment, you can report to the management regarding the malfunctioning mailbox lock since it is their responsibility to have it fixed. You will also get a new mailbox key from them if they replace the lock.

Is it legal if I fix my mailbox lock?

If it is not USPS-owned, it is your responsibility to fix your mailbox lock or replace it with a new one. However, if you are using a USPS-owned mailbox, you should not drill it or change the lock without any permission.

Report to the post office or your apartment management regarding the situation of the lock, and they will call someone who will fix it for you.


Have you solved your problem through our tutorial on how to replace a mailbox lock? It is easy to change lock on mailbox if you have the right tools and the proper steps. By mastering this tutorial, you won’t have to pay a locksmith to replace your lock.

You can share this post with your friends who also want to replace the lock of their mailbox but don’t know how to do it. We would also love to hear your experiences in following the tutorial. Just leave a comment below.

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