From http://www.masterlock.com/faq/lostcombo.shtml:
I have a brass padlock #175, #176, #177 or #178 from Master Lock that has a resettable combination. I would like to reset the lock to a different combination, but have lost the instructions for doing this. Can you help me? Models #175, 176, 177 and 178:
- Open lock with the factory set or previously set combination. The lock must be set to the current combination, or you cannot reset it. Note: the shackle must be in the open position to reset the combination.
- Insert reset tool (enclosed in package) in hole on side of lock.
- Push reset tool in and turn 90 degrees (in either direction). Reset tool automatically stays in this position.
- Set wheels to desired combination.
- Turn and remove reset tool. Lock is now set to new combination.
- Record your new combination in a safe place. (Try our new combination registration site at combolocker.com, a free service from Master Lock!)