Picture of How to Reclaim A Master Lock 4 No. Combination
Okay, so, you have a somewhat expensive Masterlock with a 4 number turning combination.  Unfortunately, you have lost or forgotten the combination that opens this particular Masterlock.  Bummer. 

With four sets of digits, opening this lock has approximately 10,000 possible combinations.  Actually, it has EXACTLY 10,000 possible combinations.

Fortunately, these locks have a very simple, intuitive lock mechanism.  The next step will briefly describe the mechanism, and subsequent steps will show you how to actually reclaim the combination, meanwhile opening the lock as well.

Disclaimer:  Don't steal people's things.

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Step 1: Inner Mechanical Workings (FYI)

Picture of Inner Mechanical Workings (FYI)
First off, if you want a detailed explanation of combination locks, pop over to Wikipedia

Imagine a Master combination lock as simply a a number of discs (or rotating dials) with notches in their inner circumference.  These notches correspond to a particular number on the outside of the disc (the part we use to unlock it).  When the correct number sequence is inputed, the notches line up, and the bolt is released.

The most important things to know are (1) all 4 numbers must be correct to release the bolt (2) as we can't see the notches, we have to rely on touch to feel when a notch is engaged or not, (3) in order to feel when a notch is engaged, we need to provide upward pressure to the bolt, and (4) in order to feel each number out correctly, we must start from the bottom up as this will allow us to know when each subsequent notch (up the lock towards the bolt) are engaged.

Enough of this.  Lets pop a lock.

Step 2: How to Feel Out the Lock

Picture of How to Feel Out the Lock
1. Take the lock in your non-dominant hand with your index finger and thumb grasping the Master logo right behind the lock dials (see the picture)

2.  Now curl your ring finger into the U-shaped space the bolt makes, and provide steady pressure, pulling the bolt outward from the lock.  If you can find a more comfortable position to hold the lock steady and provide upward pressure to the bolt, then high-five.

3.  Once steady pressure is provided, then begin with the lowest disc (towards the bottom of the lock) and turn it counter-clockwise slowly.  You should feel some tension in turning the disc.  Thats exactly what we're looking for.

4.  At some point while turning it slowly, you'll find the resistance to turning will go away.  That means the notch is lined up correctly and therefore not engaging the bolt.  It might happen very quickly, so as soon as it does, stop turning and take note of the number.  That'll be the last number of the number sequence.  Leave it at that number and continue on.

5.  Now work your way up doing this to every disc.  The last disc will be very easy to complete, if you've done it all correctly, as it will be the only notch still engaged with the bolt and the pressure will be very easy to recognize.

6.  In order to find the combination of an unlocked Master lock, simply go backwards, providing pressure down onto the bolt and working down the number dials rather than up. 


Ladreinee made it!1 month ago
Holy crap!!! I really didnt think this would work at all but good Lord it did!! My jaw dropped as soon as it popped open. Hats off to the person who figured this out!! Wow!!

No way. you need a shim. Like a .005 feeler gauge. You insert the gauge between the housing and the dial. All #'s will allow the gauge to go in a set distance. Except one. The gauge will go in a couple mm more. Do that with all 4 dials. Say the #'s are 4789. rotate each dial togeather,trying to open at each one. i.e. 4789,5890,6901,7012,etc. pulling on the hasp is useless. I use a small tape measure end about 2: long that is perfect. Has the marks at each 1/16

rsage8 months ago

That is nuts how easy that is. That's like stupid easy.

Had a lock sitting around with an unknown combo, within seconds it was open. Thankfully I'm an honest man.

Lowriderpr3 years ago
Great I did it thanks :)
manutea3 years ago
Damn ! this trick worked and saved my a** !!

thank you very much for sharing it !
sbeltran33 years ago
ThaNks this the best
St Jimmy4 years ago
Thank you. I've had this kind of lock sitting around being neglected for about a year. This is so helpful
Dr Qui St Jimmy4 years ago

Don't use this type of lock with anything valuable, they are way to easy to open.

When I worked in the hardware store we used to have one of these locks that we played a game with, see who could open a the lock the quickest without knowing the combination, we could open the lock in under 30 seconds before to long.
tranoxx4 years ago
this was my brothers lock that he forgot the combo too but i opened it!!
KnexFreek5 years ago