How to Crack a Master Combination Lock http://www.wikihow.com/Crack-a-Master-Combination-Lock If you’ve forgotten the combination to a Master Lock combination lock you have a few options. If the lock isn’t locked onto anything, you can make a photocopy of the serial number and send that into Master Lock for the combination . If, however, your lock is attached to something, you can break the lock, call a locksmith, use a shim, or figure out the combination. Of these options, only the last will leave you with a usable lock without lightening your wallet. Unfortunately, there are 64,000 possible combinations on a standard 40-number Master Lock. With this method, however, you can quickly narrow that down to 100 combinations, a workable number to try if you’ve got a few minutes. Steps Make sure you have a Master Lock and check the lock’s serial number on the back. This method only works with Master Lock combination locks, and may not work with all of them . Turn the lock’s dial clockwise to zero. It is a good idea to turn it three rotations first, just to make sure it’s clear. Apply steady tension to the shackle and turn the dial clockwise. The shackle is the u-shaped part of the lock that goes around whatever you’re locking. To apply tension you can either pull the shackle up while holding the lock, or you can pull the lock down if the shackle is locked onto something solid. Turn the dial slowly as you apply tension. If you can move the dial only slightly, you have found your first sticking point. Note the center of the sticking point, as you apply tension and move the dial as far to both sides as you can. You will see if either the center is more in between two numbers or if the center is more at an actual number. If the center is a number, write it down. If the center is between two numbers you don't have to write it down. Release shackle tension and turn the dial clockwise slightly past the sticking point. Then find the next sticking point by reapplying tension. Write it down if the center of the sticking point is a whole number. Find the third number of the combination. If you have done it correctly, you should now have 5 numbers. One of these numbers sticks out; it is the number whose last digit differs from all other numbers. For example if you have the numbers 2, 12, 22, 27, and 32, only one number ends with 7. That means that number is your third number! If you do not have five numbers like this, you have done something wrong. You have not written down the correct sticking points. There are 12 sticking points in total, which you can make sure to find. Then find out which of those sticking points that seem to most likely have their center at a number. Your lock will have only 5 numbers with 4 having the same digit. If it's hard to find, take note that the center might not be exactly at a number, but closer to a number than between a number. Find the magic number. Divide the third number by four and write down the remainder. In this case 27/4 = 6 remainder 3. Remember we are only concerned with the remainder, which will always be 0, 1, 2, or 3. Write down the magic number (3 in this example). You may want to circle it for clarity. Find the possible first numbers of the combination. Add 4 to the magic number (3). Write down the result (7). Now add 4 to that and continue adding 4 to each resulting sum until you have gone completely around the dial once. Write down each of these numbers. Thus, for the example above the numbers would be 3, 7, 11, 15, 19, 23, 27, 31, 35, and 39. One of these numbers is the first number of the combination. Find the possible second numbers in the combination. If your magic number is 0 or 1 then add 2 to it, otherwise subtract 2. Since our example magic number is 3, we subtract 2 and get 1. Write down the answer and add 4 to it. Now add 4 to each resulting sum until you have gone completely around the dial once. Thus, in the example, the numbers would be 1, 5, 9, 13, 17, 21, 25, 29, 33, and 37. One of these numbers is the second number in the combination. Figure out the correct combination by trial and error. You now know all the possible first numbers [3, 7, 11, 15, 19, 23, 27, 31, 35, 39], all the possible second numbers [1, 5, 9, 13, 17, 21, 25, 29, 33, 37], and the third number [27]. You’ve just narrowed down 64,000 combinations to only 100. Try each combination until you find the correct one. If you’re lucky, you may need to try only a few. Then again, you may need to try all 100. Tips Check out the video! Link below. After cracking just one lock, the system becomes much easier to understand, so hang in there. The correct sequence for turning the dial to open a Master Lock is to turn the dial clockwise to the first number, then turn it counterclockwise twice to the second number (you must pass the first number on the way), and finally clockwise again directly to the third number. If you want to go the easy route and have Master Lock give you the combination, you can make a photocopy of the lock showing the serial number and mail it to the company with a form (which you have to have notarized) available on their website. The photocopy must show that the lock isn’t locked onto anything, so if yours is attached to your shed door or bike chain, they won’t help you. They also won’t be able to provide the combination if you have a resettable lock, since the owner sets the combination on those. If you’re in a hurry, you don’t need to calculate the possible first and second numbers yourself. Once you’ve figured out the third number, you can save time by using a special computer application to determine all the possible combinations. See the External Links section below. Though not necessary, you may find it helpful to write out the combinations methodically so you don’t forget which ones you’ve already tried in the middle of the next step. Thus, you could make a chart with all the combinations (3-1-27, 3-5-27… 7-3-27… etc.) This method may not work with newer Master Locks. It is rumored that Master Lock changed the combination algorithm on some of the newer locks, in particular those with serial numbers starting with the number 800. Some people, however, have reportedly had success cracking these with this method, too, so it may be worth a try. Warnings In some situations this can be considered breaking the law, so use this technique appropriately.