Master Lock 5400D Key Box Jammed: Tried & Tested Practical Fixes

Key Takeaway

  • Master lock 5400D key lock box jammed issue can manifest as dials becoming hard to turn, release button not responding and inability to open despite the correct combination.
  • Regular maintenance, such as cleaning and lubrication can prevent and resolve jamming problems.

I have been using the Master Lock 5400D lock box for quite some time now, and it’s safe to say that it has lived up to its reputation as one of the best key lock boxes around. In fact, I have also done a detailed review of 5400d

However, even the best locks can face occasional challenges. Recently, I encountered that my Master Lock key box was jammed. While I was able to resolve the issue, I couldn’t help but think about fellow users who might encounter a similar predicament. 

So, I decided to explore the potential causes behind the Master Lock 5400D jamming issue and pen them down in this article.

Identifying the Jamming Issue

Identifying the Jamming Issue

In my experience, the jamming issue in a Master Lock 5400D typically manifests in the following ways:

  • Difficulty Turning the Dials: The combination dials become hard to turn, and there is a noticeable resistance when trying to input the combination. 
  • The Release Button doesn’t respond: Even after entering the combination, the release button gets jammed and doesn’t respond.
  • Inability to Open: Despite entering the correct combination, the lockbox refuses to open, leading to frustration and inconvenience.

Troubleshoots For Jamming Issues

Troubleshoots For Jamming Issues

If Facing Difficulty in Turning the Dials or Release Button

If you face difficulty with dials or the black release button, the root cause for the same is accumulation of dirt (and debris) and rusting. 

The dials (and the release lever) in 5400d are made of metal with a decent number of crevices around that can accumulate dirt and debris if not covered properly. Along with dirt, these parts also get rusted along with time which leads to the jammed lock box.

First Thing To Try

I will advise you to try out this fix first. This is a more practical solution that worked for me.

  • Press the upper part of the gray body tightly. You will hear a clicking sound of the latch.
    clicking sound of the latch
  • Try to rotate the dials to the correct combination and then pull the release button.

In most of the cases, this hack will work with you. However if this doesn’t help, then there is a more traditional way of dealing with the problem.

Traditional Solution

  • Start by gently tapping the key box with a rubber mallet to loosen any rust or debris.
  • Use a penetrating lubricant like WD-40 or a similar product. Apply the lubricant generously to the key box’s moving parts, focusing on the rotating dials and the release lever. 
  • Allow the lubricant to penetrate for a few minutes, then attempt to open the key box again.

Inability to Open

If you feel that rotating dials and the release button are not the culprit for causing the jammed key lock box, then it has to be the hinges inside the latch mechanism. It happens due to hinges getting rusted with time.

Inability to Open

While you can ensure that hinges don’t rust with the help of WD-40 or other lock lubricants, what should you do when it has already happened?

Rusted hinges become stubborn that need a little bit of beating. 🙂


  • Try hitting the upper part of the gray body lightly with a hammer. Since this part is on the opposite side (outer) of the hinges (inside), tapping it with a hammer makes the hinges more responsive in nature.
  • While this method is not a foolproof method, it works every time I face a similar situation.


Dealing with a jammed Master Lock 5400D can be frustrating, but with proper troubleshooting and maintenance, most issues can be resolved. Regularly cleaning and lubricating your lock box, protecting it from harsh weather, and verifying the combination input are all essential steps in preventing and addressing jamming problems. 

Remember that if all else fails, contacting Master Lock’s customer support or seeking assistance from a professional locksmith can provide the solution you need to keep your key storage secure and reliable.

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Hey! I am Mark. Though I am not a locksmith by profession, but locks have always fascinated me since my teens. And it all started when I got locked out of my house and I had to pick the lock. Since then it has become my hobby to learn more about different kinds of locks, understand their working and methods to pick them up. In due course of time, I have also become better aware of how installing the right lock goes a long way in ensuring iron clad security. I aim to share my passion (about locks) through this blog. If you are also passionate about picking locks or are just looking to beef up the security, hop on the ride.