Rekey or Replace After Buying a House in Brockton

Published 21 September 2026

The keys handed over at a closing are the ones the sellers happened to have. They are not a complete set, and nobody can say how many other copies exist - a contractor, a former tenant, a neighbor who watered plants. That is why the locks get attention in the first week.

Two options sit in front of a new owner. Rekeying keeps the hardware on the door and retires every key that opens it. Replacing puts different hardware there entirely. Which one fits depends on the lock and the door, and it rarely lands the same way on every door.

Rekeying is work inside the cylinder, not on the door. It is replacing the old lock pins with new lock pins. Each chamber gets a pin whose top sits flush with the shear line when the new key is inserted, which lets that key turn and the old one fail.

The stated purposes of rekeying are to eliminate compromised keys and to make a set of locks share a common key. A house that has just changed hands is the first by definition. The hardware goes untouched - same deadbolt, same finish, same strike, same holes - which is why rekeying a house after a closing is the usual starting point when the locks are sound.

Rekeying assumes a cylinder worth keeping. A cylinder that binds, a bolt that has to be helped into its strike, a knob that spins loose on its rose - those are hardware problems, and new pins fix none.

Grade is the other reason to swap. Residential deadbolts fall under ANSI/BHMA A156.40, where a certified deadbolt or lockset is rated Good (C), Better (B) or Best (A) for security, durability and finish. Under ANSI/BHMA A156.13 for mortise locks, Grade 1 is tested to one million cycles against 800,000 for Grades 2 and 3, and the ram impact test runs ten blows at Grade 1, five at Grade 2 and two at Grade 3, each at 75 foot-pounds. Hardware near the bottom of that range is where how a rekey is priced next to a replacement comes up.

• The key must be jiggled before the cylinder turns
• The bolt will not throw fully unless the door is lifted
• The lock has no removable cylinder to take new pins
• Three doors carry three brands but need one key

Front doors get counted. The rest surface a week later, when somebody needs to get through one. A walk of the exterior beats describing it by phone. On a Brockton three-decker that means the front entry, the rear porch door on each level and the common basement door; out toward Montello it is more often a back slider, a bulkhead and a service door into the garage.

Two openings get skipped nearly every time. The interior door between an attached garage and the house is an exterior door for security purposes, since anyone with the garage open is already past the outside wall. A storm door with its own cylinder is a second lock on the same opening, on its own key. Where a unit is occupied, what the rules say when a unit changes hands between tenants is worth reading first.

• Rear and side entries, including the porch door on each floor
• The basement door and the bulkhead, which often take a different key
• The service door into the garage, and the door from garage to house
• Padlocks on sheds, gates and utility closets, which can be pinned to match

A fully rekeyed house still opens to anyone holding a garage remote or a door code. Those credentials live in memory rather than in a cylinder, and a lock change leaves them untouched.

Garage openers clear in one step. On Chamberlain and LiftMaster units the LEARN button on the opener is held until the LED turns off, roughly six seconds, and all previous codes are erased. Every remote and keypad that should keep working is then reprogrammed - anything else is finished.

Smart locks need their own pass. Schlage residential electronic and smart locks ship with two default user codes and a default programming code; those defaults can be removed, and pairing the lock to the manufacturer app deletes them. A factory default reset deletes all codes and restores the factory codes and local lock settings, but on a Z-Wave model it does not reset the Z-Wave settings or unenroll the lock, so a lock reset at the door can still sit in somebody else's system.

One key for every door is the most common request after a purchase, and usually achievable. Making a set of locks share a common key is one of the two standard reasons to rekey, and locks with a cylinder, mechanical or smart, can be keyed alike or rekeyed.

The constraint is the keyway, the shape of the hole the key fits into. A single keyway family is what makes a unified or hierarchical keyed system possible, so doors carrying different brands cannot be pinned to one key on their existing cylinders. Some get swapped so the house sits in one family, which is where a rekey becomes a partial replacement.

Open keyways use blanks no longer under patent protection, so copies can be cut almost anywhere; restricted keyways are controlled by the manufacturer and sold only to authorized buyers. Master keying, where one key opens several doors that each keep their own, belongs in the plan before pinning starts; a walkthrough with a residential locksmith in Brockton is where that gets settled. For a door that arrived with no key, getting into a house with no working key is a separate errand.