Master Lock MLK5400D Instruction Manual

1. Introduction

This manual provides comprehensive instructions for the setup, operation, and maintenance of your Master Lock MLK5400D Locking Combination 5 Key Steel Box. Please read these instructions carefully before using the product to ensure proper function and security.

Figure 1: Front view of the Master Lock MLK5400D Key Box, showing the combination dials and shackle.

2. Safety Information

Always observe the following safety precautions:

• Do not attempt to force the lock mechanism. This can cause damage and void the warranty.
• Keep the key box away from extreme temperatures and harsh chemicals, which may affect its material integrity and functionality.
• Ensure the combination is set to a memorable sequence that is not easily guessed.
• Regularly check the shackle and body for any signs of wear or damage. Discontinue use if significant damage is observed.

3. Package Contents

Your Master Lock MLK5400D package should contain the following item:

• One (1) Master Lock MLK5400D Locking Combination 5 Key Steel Box

4. Setting Your Combination

The Master Lock MLK5400D comes with a preset combination (usually 0-0-0-0). Follow these steps to set your personal combination:

1. Open the Key Box: Enter the current combination (factory set to 0-0-0-0) and pull down the shackle to open the key box.
2. Locate the Reset Lever: Inside the key compartment, locate the reset lever. It is typically on the back wall or side.
3. Move the Reset Lever: Using a small, pointed object (like a pen tip), slide the reset lever from position A to position B (or from UP to DOWN, depending on the model).
4. Set New Combination: With the reset lever in the reset position, rotate the dials to your desired new combination. Choose a combination that is easy for you to remember but difficult for others to guess.
5. Return Reset Lever: Slide the reset lever back to its original position (position A or UP). This locks in your new combination.
6. Test New Combination: Close the key box and scramble the dials. Then, enter your new combination and open the key box to verify it works correctly.

Figure 2: Side view of the Master Lock MLK5400D Key Box, illustrating the shackle mechanism.

5. Operating the Key Box

To use your Master Lock MLK5400D Key Box:

1. Open the Key Box: Rotate the combination dials to your set combination. Pull down the shackle to open the key box.
2. Insert/Remove Keys: Place the keys you wish to store inside the compartment. Ensure they fit without obstructing the closing mechanism.
3. Close and Secure: Close the shackle firmly until it clicks into place.
4. Scramble Dials: After closing, scramble the combination dials to secure the key box and prevent unauthorized access.

Figure 3: The Master Lock MLK5400D Key Box securely mounted on a door, demonstrating its typical application.

6. Maintenance

Proper maintenance ensures the longevity and reliable operation of your key box:

• Cleaning: Wipe the exterior with a soft, damp cloth. Avoid abrasive cleaners or solvents.
• Lubrication: Periodically apply a small amount of silicone-based lubricant to the shackle and internal moving parts to ensure smooth operation, especially in outdoor environments.
• Inspection: Regularly inspect the key box for any signs of wear, corrosion, or damage. Address any issues promptly.

7. Troubleshooting

If you encounter issues with your Master Lock MLK5400D, consider the following:

• Key Box Will Not Open:
  • Ensure you are entering the correct combination. Double-check each digit.
  • Make sure the dials are aligned precisely with the indicator marks.
  • Apply slight pressure to the shackle while entering the combination, then release.
• Dials Are Stiff:
  • Clean the dials and apply a small amount of silicone lubricant.
  • Ensure no debris is lodged between the dials.
• Forgot Combination:
  • Unfortunately, if the combination is forgotten and the key box is locked, there is no master key or backdoor to open it. You may need to contact Master Lock support for options, which might involve professional assistance or replacement.

8. Specifications

9. Warranty and Support

Master Lock products are manufactured to high-quality standards. For specific warranty information or technical support, please refer to the official Master Lock website or contact their customer service directly.

Master Lock Official Website: www.masterlock.com