How to Change a Masterlock Combination

Master Lock is one of the most widely recognized names in combination, and other types, of locks. Some Master Lock combination locks come from the factory with a pre-set combination that must be used for the life of the lock, other combination locks come with a pre-set combination that can be changed several times or a pre-set combination designed to be used once so the owner of the lock may choose his own combination.

Instructions

Models 175, 176, 177 or 178

1. Open the lock, using either the factory pre-set or the most recent combination.

2. Open the shackle. The shackle of a lock is the U-shaped part that goes into the lock body to close the it.

3. Insert the reset tool into the hole on the side of the lock. Turn the tool a quarter turn in either direction. The reset tool was included when you purchased the lock.

4. Move the wheels to the new desired combination. The reset tool should still be in the lock. When the wheels have been set, turn the reset tool a quarter turn in the opposite direction.

5. Remove the reset tool to finish setting the lock to the new combination. Record the combination somewhere safe in case you forget it.

Models 1520D, 1523D, 1524D or 1534D

1. Open the lock and remove the shackle.

2. Remove the spring-loaded metal end cap from the lock.

3. Remove all the combination wheels.

4. Reinstall the combination wheels so your desired combination is lined up with the Master logo on the front of the lock.

5. Replace the metal cap on the end of the lock opposite the metal cap with the logo on it. Close the shackle and spin the wheels to lock it. Make sure the metal wheels are right side up. Record the new combination and store it in a secure place.

Model 643D

1. Set the wheels to 0-0-0-0 and remove the shackle.

2. Turn the shackle a quarter turn counterclockwise. Press the shackle down.

3. Set the wheels to your desired combination while holding the shackle down.

4. Release the shackle and return it to the closed position.

5. Scramble the wheels of the lock to lock it. Record and store the combination somewhere secure.

Model 643DWD

1. Set the wheels of the lock to P-L-A-Y so the middle of the letters are lined up with the red stripe on the lock.

2. Remove the shackle of the lock and turn it a quarter turn so its notch is lined up with the lock body's notch. You will see the notch on the outside of the lock.

3. Press the shackle down and hold it there. Turn the wheels to your new four-letter combination, lining the middle of the letters up with the red line.

4. Release the shackle and return it to the closed position. Hold the shackle down in the closed position while you scramble the wheels of the lock to lock it.

5. Record and store your combination in a secure place.

Model 653D

1. Set the wheels of the lock to 0-0-0-0.

2. Remove the shackle and turn it a quarter turn counterclockwise.

3. Press the shackle down and turn it another quarter turn in the same direction.

4. Set the wheels of the lock to your desired combination while still holding the shackle down.

5. Keep holding the shackle down while turning the shackle a quarter turn clockwise. Release the shackle and turn it back to the closed position. Record and store your new combination in a secure place.

References

• Master Lock: Frequently Asked Questions

Resources

• Master Lock Vault: Store Your Combination Safely