My back door (which is only two years old) has a door knob that recently suddenly stopped turning. I can lock and unlock it, but it just won't turn. Here's a picture of the inside of the door knob:
The very center bit is the lock mechanism, and I can turn it (locking and unlocking it) easily with a hex key. The half-circle immediately next to it appears to me to be the mechanism for opening the door — I could be wrong about that, though. It will not budge. The only two options I can see now are:
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taking the door off its hinges so that I can completely remove the lock set and possibly replace it with a new one; or
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calling a lock smith.
I'm more inclined to go with the latter than the former. Any other suggestions?
Best Answer
In its currently disassembled state, there is nothing locking the mechanism. You are correct that the C shaped half-circle shaft is what pulls the latch back when turned.
If you cannot push the latch back with your finger, the anti-jimmy device has had a piece break in it.
I had this happen on a bathroom door latch about two weeks ago, probably made by the same manufacturer as the shape of the lock actuator rod and latch actuator are exactly the same.
If you look at it, the lock actuator rod (the center piece you were turning) has a taper section just where it passes through the latch pull which means that during assembly, you manually push the latch back and it passes straight through.
In order to get clearance so the lock actuator rod will pass through, I pried the folded piece that they pass through till I got clearance so the shafts would pull out. I then squeezed the folded piece back together and pushed the latch out. It didn't even require taking the door off the hinges.
Replace the whole door knob/latch assembly with new and you're back in action.