How to Fix Antique Mortise Door Mechanisms

A good cleaning and some spray lubricant will get most locks working.

Antique doors and hardware have a richness and patina that is very special. There are two main problems with using old hardware. First, their age makes them prone to break down due to their long life of productive use. Second, once they do break, parts are not always readily available to make repairs. Many old locks simply need a good cleaning and a little TLC. For truly broken locks, modern hardware manufacturers have come to the rescue for do-it-your-selfers without locksmithing skills, in the form of modern hardware to fit most old mortised doors.

Things You'll Need

• Paint remover
• Steel wool
• Screwdrivers
• Spray lubricant
• Turpentine
• Replacement lock

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Instructions

1. Remove the door from its hinges by driving the pins up from the bottom with a hammer and screwdriver. Lay the door on a flat, steady surface.

2. Apply a coat of gel paint remover to the faces of the lock to remove the paint and expose the screws. Tape off any areas of the door that you do not intend to strip. Allow the label-recommended working time and then scrub the stripper and paint from the lock with steel wool. Flip the door over and repeat on the reverse face. This will uncover the screw heads and help to prevent damaging the heads.

3. Remove all mounting screws in both faces and the edge of the door. Use a screwdriver to prevent slippage. Save the screws by placing them in a zippered sandwich bag.

4. Loosen the knob screw, typically found at the base of the knob, running into the square shaft of the lock mechanism. Remove the knob and slide the shaft out of the lock.

5. Pry gently against the face plate on the edge of the door with a flat screwdriver until the lock comes loose. Slide it out of the door. Reinsert the square shaft and test the latch. If the striker withdraws when the knob is turned and springs back when released, any latch problems are probably caused by sagging hinges. Tighten the hinge screws into the jamb. Replace stripped screws with slightly longer ones for a snug fit.

6. Scrape any residue or remaining paint from the lock bolt on the door edge face of the lock. Spray the lock with lubricant. Insert the key into the hole. If the key turns, but resists, add more lubricant. If the key is stuck, use a knife point to scrape around the end of the bolt to remove obstructions. Continue lubricating and working the lock until movement is normal.

7. Soak the lock in turpentine overnight and wipe it down with a clean rag. Most locks will regain function after cleaning. Internal repairs are best handled by a locksmith, due to the small and fragile nature of the pieces inside--which vary vastly from lock to lock.

8. Replace locks that are badly damaged with a mortise lock of the same size. Most hardware stores carry some and can special-order locks. Install the lock in the reverse order of removal. Set the lock into place, reinsert the shaft, attach the knob and install the mounting screws. Replace damaged screws for best results. Take the old screws with you when shopping to ensure proper size.

References

• "Replacing Locks and Adding Deadbolts": Bob Doyle; Sunset Books, 1999
• Home Tips: Fix Door Latch Problems