American Lock 747
Among the largest of the American padlocks, the 747 came in two varieties. This lock is only available with a protected shackle. From the front, aside from logos which changed over the years, the 747 looks the same.
The difference between the two varieties is in how the lock is taken apart. One version has a sliding piece of metal on the bottom, the other has a screw-retained core retainer and small metal shield.
Both versions came as default with a 'restricted' keyway.
The screw-retained core version comes apart as follows:
Remove the screw from the shackle toe hole
Retainer is now removed.
Sliding core protector is next.
Now the core.
Press down on the shackle to ease tension on the locking balls, and tap lock on hard surface to remove the cam. The locking balls will fall out once the cam is removed.
Side view and top view of the locking cam.
Now remove the shackle retaining screw. This comes from the factory filled with a grey epoxy (like J.B. Weld). Use a pointed pick to remove the epoxy, then an allen wrench to remove the screw.
The shackle and spring now can be lifted out of the lock.