Irritating. And cold! So my wife mandated that this was to be the task today, and so mote it be.
Before weatherizing the door, though, I first had to rehang it so it would actually close correctly. The culprit in this case was the top hinge, pictured here. Oy. My guess is this hinge was damaged by a tenant trying to gain access after losing a key, and the "obvious" way to fix the hinge was to use longer screws, and drive them in with a drill, thus tearing hell out of the heads. Note the attempt to angle the screws, because the wood under the hinge is splintered.
So we take off the door, and the inside trim; wow! The frame is really not very thick! And shows the imprints of lots of historical hinges; my guess is this frame is original. Certainly it's older than you or me, anyway, and as we can see, there is a lot of open space behind it. Also a lot of dirt; really, to clean a house thoroughly, it has to be disassembled first.
Note, incidentally, the view of the sunroom of the big house in the background. Just to orient you here.
Anyway, here's why these screws didn't hold the door up; the threads are mostly not in the wood. The screw was long enough to extend into the bricks behind it, but probably not long enough there to get sufficient purchase, and the outer two screws are just hitting the plaster anyway. Useless.
So all I did was to remount the hinges with reasonable screws, using a trick I learned from my uncle: coat a toothpick with Elmer's glue, and stick it into the stripped hole before inserting the screw. Works a charm.
The bottom of the frame was also loose for lack of support, so I put a brick under either end of the threshold and drove in some shims to force it up against the frame, and thus the frame up against the bricks above it. Much solider now (oh shims, is there anything you can't improve?)
Once the door was rehung, it turned out that the strike plate was in the wrong place (it was right for a modern doorknob, but this door has antique knobs, so the strike plate needs to be about a quarter inch further into the frame). So I moved it, and adjusted the strike plate for the deadbolt.
As a result, amazingly, the door is now square to the floor. Wow. It's actually a pretty good door, although clearly it needs some paint. As you see, after I removed the threshold, there's actually a lot more gaping space there (a problem to be resolved tomorrow) - but instead of closing laboriously with a squeak-BLAM, it can now be pushed closed with one finger, and stays closed, and you can unlock the deadbolt even with your groceries and the umbrella in your other hand.
This is the kind of thing that makes me feel successful in this endeavor.