Enter the current combination on your Brink's safe and open the door.
Look for a button on the back of the door. In most cases, this button is small and red. Press the button and hold it until it beeps and the keypad lights up. This clears the current combination code.
Enter your new combination on the keypad. This combination must be a series of three to eight numbers.
Press the "B" button when you're finished entering your new combination. The safe should beep twice and then a yellow light will appear, signaling that your new combination code is set.
Test the lock to make sure it works. To do this, close the lock handle, but not the actual safe door. After five seconds have passed, enter your new code, followed by the "A" button. Check the lock handle to see if it opens successfully. If it does not, enter the code again. If you're still unsuccessful, reset the combination again and repeat.