Does it work with the door open?
This is a useful detail to share, if you can check it safely without locking yourself out. A mechanism that works normally with the door open but binds when it closes may be meeting resistance at the frame. Replacing the cylinder alone may not solve that.
Do not force a key, slam the door repeatedly or keep tightening screws at random. A small fault can become harder to diagnose after several improvised fixes. Describe the symptom and when it began instead.
If the door is already locked and you cannot get in, use our emergency service. If it still opens, a planned visit may help you address the problem before it turns into a lockout.
Older hardware deserves more than a guess
In older Bronx apartment buildings, the shape and preparation of a door can limit which replacement parts fit. A mortise lock set into the door is different from a typical bored deadbolt. A new unit that looks similar in a photo may have different dimensions.
The assessment should consider the cylinder, the operating mechanism, the handle and the points where the lock meets the frame. Some faults can be repaired; others require a part or a replacement assembly. Parts availability and compatibility affect the decision.
A finish that matches the rest of the door may matter to you, too. Say so before replacement hardware is selected. With a managed entrance, confirm who can authorize the work and whether the building has its own specifications.
Repair, rekey or replace?
These options answer different questions. Repair addresses a fault. Rekeying changes which key works in a compatible lock. Replacement changes the hardware itself. Sometimes a job involves more than one of them, but they should not be treated as interchangeable.
A sound lock with a lost key may be a candidate for rekeying. A broken or badly worn mechanism needs a different conversation. Tell us what you want to achieve as well as what feels wrong.
Once the proposed work is clear, review the price before it begins. When the job is complete, check the key and handle with the door open and closed. The goal is a door you can use normally again, without the small routine of pulling, lifting and trying twice.