The deadlock on our front door has worked fine for 2.5 years. You could hear a "clunk" when it was turned. Now, all of a sudden, the latch slides over silently with no resistance. The major problem though is that when you try to lock it with the key from outside, it unlocks when the key is turned back for removal. The resistance, or 'weight" of the latch is simply too low. I have taken it apart twice but can't really find anything wrong with it, except it moves too easily. Help please!