My front door has a mortise lock on it that's probably 80 years old. About a week ago, I was unable to turn the inside door knob to open the door, nor push the lever on the exterior handle. The door locks and unlocks just fine. I took off both the handle and knob, but the spindle was stuck. I was able to use pliers to turn and remove the spindle (it's a split spindle), but still no luck on opening the door. The latch bolt seems stuck.
About 3 weeks ago, I noticed that a screw on the plate near the latch bolt was protruding. I think my door is shifting a bit. I'm not sure if this has anything to do with it, but there is enough clearance for the screw to pass through the entryway, so I don't think that's the problem.
A locksmith claims that he can remove it, but it'll cost over $100 just for him to remove it and near $400 bucks to replace it. Any suggestions?