Are you referring to the PKPT (Push Key Pin Tumbler) padlocks, originally made by Yale?
If so, yes, a number of us take them apart for servicing.
The lock is picked open, and the brass fitting is partly unscrewed on the side without the shackle. This is the first step in disassembly. You will need to make a square end tool to turn that brass fitting.
With that fitting removed, look into the hole. You will see this spring. Have pulled it away from the shackle side of the lock. Then the shackle can be removed from the lock. A plug follower is not a bad idea when removing the shackle.
This is the plug part of the shackle. Pay particular attention to the fourth hole. The fourth hole has a larger diameter key pin which
can not be lifted above the shear line. This works as a kind of adjustable warding. The tip of the key will need to be filed down to this level in order to fit the key fully into the lock.
Pins from the lock. The driver pins are serrated mushroom pins, and the key pins are serrated. There is a bit of wear on these pins, which is to be expected considering the age. The pictures are from my old phone, so you can not see the serrations very well, but all the pins are serrated.
Gordon
Just when you finally think you have learned it all, that is when you learn that you don't know anything yet.
