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How To Replace a Mailbox Lock in Under Five Minutes

Although we normally focus on Technology, I love handy DIY tricks, so I thought I’d share this little adventure I had a few days ago.

Recently I moved into an older home and found the mailbox key had issues opening the lock. After a few weeks, the mailbox key refused to open it. Great! No matter what I tried (graphite powder and spray included), after a few days of not being able to get my mail, I knew it was time to replace the lock.

I started the adventure by calling my local post office, and that was a waste of time. They suggested a local locksmith and hung up on me. Yelp pointed me at a local locksmith who quoted me $250 for an onsite replacement plus an additional $150 an hour after 30 minutes.

So yeah, you can guess the path we’re going to take on this one. Time to get medieval on the mailbox lock!

Thankfully I have a cordless drill, so I grabbed a bit that fit nicely into the key hole of the lock. The primary goal here is not damaging the housing holding the lock so don’t use a lot of pressure when drilling into the lock. Just drill straight and apply consistent pressure.

Note: If you’re not the adventurer / handy type or if you don’t have a drill, wait for you mail carrier. They will have access to the back of the mailbox, and you can perform the steps below from inside the box. It’s not nearly as fun, but that is another option.


Once you drill through the entire lock mechanism, the mailbox door should open easily.


Slide the lock bar and metal clip holding the lock mechanism against the door. In some cases, the lock nut may still be attached to the lock. Use a wrench to take off the nut (although, in my case, the drill took care of that for me).


Without the clip holding the lock in place, popup the entire mechanism and bring it to a local locksmith. In my case, although my original lock was 15-years-old, he had an exact match that cost me just $12. Amazon has mailbox locks for under $10 if you can wait a day for them to arrive.


Once you have the new lock, slide it into the lock housing the reattach it in a locked configuration (lock bar out).


Screw on the nut and you’re done!


The new mailbox lock I purchased was a bit sticky. I solved this with a little Graphite Powder. Amazon has it listed for ~$5 however I found it at a local HW store for under $2 the next day.


In all, the entire job took no longer than 5 minutes (not counting the trip to the locksmith). Not bad considering the quote from the locksmith $250. I’ve always enjoyed DIY projects especially the ones with a drill involved. It’s an excellent bonding opportunity for my son and me, and a good way to show with a little work, almost any job is possible with a little time and patience.

Is it Legal to fix your Mailbox Lock?

Since publishing the DIY mailbox lock fix, several readers have expressed concern about the legal aspects of fixing your mailbox lock yourself. Although I can’t give legal advice, I did find a page on regarding mailbox maintenance. Along with a guide on how to install a new mailbox, it also provides guidance on maintenance.

USPS.COM: Mailbox Maintenance

Mailboxes take a beating from the weather, so we recommend an annual mailbox checkup to avoid damage to your mail or difficulty identifying your address.

  • Tighten loose hinges on the door
  • Take care of rusty or loose parts
  • Replace missing or faded house numbers
  • Keep the path to your mailbox clear

Based on this information directly from the United States Postal Service, it’s clear that the responsibility for maintenance and care of the mailbox falls on the property owner/manager.

13 Responses to How To Replace a Mailbox Lock in Under Five Minutes

  1. Simon H August 14, 2013 at 12:54 am #

    I like it. We dont have those mailboxes but just started wireing our whole house with CAT6 including HDMI over CAT6 and its clear that technology and DIY often go hand in hand. In my case followed by a spot of first aid.

  2. Ryan September 23, 2015 at 8:23 am #

    Sadly this is not an option for me. The mail person actually threatened to call the police and have me arrested when I tried to follow the “wait for mailman” part. Despite having an ID which listed the exact residence which matched the box I required to be opened. The postal office itself told me if I opened it by any means other than my assigned key that mail would no longer be sent to me, and I would have to start picking it up via the postal office branch. Then told me they could have one made for me in “as little as two weeks” and they would hold my mail for me at the local branch, and I could start going to pick it up all the way out there. Every day. And it would only cost me 150 dollars. Entirely bullshit. The postal service is taking their near federal mandated monopoly on daily mail service to a nice half assed level.

  3. Sarah October 12, 2015 at 7:36 am #

    This is so illegal do not stick a drill into your mailbox! If anyone were to report you doing that you’d be a felon.

    • Steve Krause October 12, 2015 at 8:37 am #

      I called my post office and they told me I could replace it myself. Are you sure?

  4. Sarah October 12, 2015 at 8:46 am #

    I suppose it could vary from state to state but from what I’ve read.. once a mailbox is put into use by the post office, it is federal property. If you tamper with federal property, you could potentially be charged with a felony. The post office told me they would have to put my mail on hold for up to two weeks until they could replace the lock and keys. Seems risky to me to replace it yourself!

    • Steve Krause November 14, 2015 at 8:34 am #

      Wow, that’s crazy. Here at my place the post office told me to call a locksmith because they don’t have anything to do with the mailbox. I wonder if that’s just a lazy post office or???

      Reminds me — when a friend bought a house recently, it came with no mailbox. We called the post office and they said we needed to go to Home Depot and buy a post and a mailbox and set it all up. Later, he calls me because he lost his key. Again, the post office said — not our problem so…. I used my handy tip above and we were in and out in 2 minutes (he didn’t own a drill or else I would have just told him to do it himself…).

      Since the Post office is federal, I’m going to guess it’s all dependant on the local postmaster?

      Are any lawers reading this? Input?

  5. De November 14, 2015 at 1:47 am #

    I live in CT. Can I do this on my own?

    • Steve Krause November 14, 2015 at 8:35 am #

      If you have a drill and a new lock — Yes.

      However I can’t give you any legal advice. But that being said, if a locksmith is allowed to do it, not sure why a home owner can’t….

  6. Steve Krause November 14, 2015 at 3:35 pm #

    I’ve done a lot of searching over the past hour and honestly, it appears to be all across the map in regards to the legality of fixing your own mailbox. Some articles I’ve read say you can have the post office do it, others say you need to have your apartment complex or HOA take care of it and others say you can do it yourself or hire a licensed locksmith.

    With these things in mind, my logic tells me if the HOE or Apartment ownership can fix a lock, then I the owner can fix it… Granted, I’m no attorney however after reading the article on, I feel confident that it’s not illegal to fix my mailbox and maintain my mailbox as needed:

    If you review that web page, it has a section under Maintenance which includes things you should fix/replace as needed. With that in mind, my conscience is in the clear. :)

    I hope this all helps anyone out there with this question.

  7. Shockersh November 14, 2015 at 10:00 pm #

    Awesome. And here I thought you were just a geeky Technology dude.

    Groovy indeed.

  8. Michael November 16, 2015 at 4:55 pm #

    Some mailboxes are owned by the USPS, but I think most are not. So everyone should call their local postmaster and give them the address, they will tell you what to do – to either get a key through them or that you are on your own. Write down the name of the person who gave you permission to replace the lock, and be clear that you are going to replace the lock with a new one and not just re-key it.

    Another safe idea besides calling the local postmaster is to just ask the USPS delivery person, they deliver mail around the same time every day all you have to do is be there when they come and ask them. Make sure you ask specifically if you can “replace the lock with a new one”.

    I think that whoever tells you its okay to replace the lock on your own, write down their name in case someone does ask who gave you permission to do it. To avoid confusion, don’t drill out a lock at night and probably not right in front of the postal delivery person unless they were the one that told you to do it. Of course, always have a valid ID that matches the address in case someone were to stop you and ask you what you are doing.

  9. Kevyn November 17, 2015 at 11:25 am #

    I change these out weekly for my local Post Office. It costs $23 if it’s a new lock replacement (new resident). I do it for free if the customer has the old key and the lock doesn’t work anymore or the key has broken off in the lock. Some of the cluster boxes are owned by the Post Office and some by property owners. The Post Office is responsible to repair their cluster boxes and property owners are responsible for theirs. If a door is broken or bent and it’s ours. We’re required to fix it, if we don’t own it the property owner is required to fix it. Check with your local Post Office to find out who’s responsible for your cluster box. If the Post Office owns the cluster box, it’s a Federal Crime to mess with it.

  10. Mark P. November 18, 2015 at 9:22 pm #

    I am a locksmith in here in Central California, we see these mailbox locks on an almost daily basis. Our rule of thumb is that of the group box is shiny and has a visible eagle logo on it, leave it alone. If it looks like it has been painted a few times but done maintenance guy you are good to go.

    But I am not a lawyer just a locksmith that has had Police and the postmaster called on him.

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