Mailbox Lock Replacement across greater Los Angeles, Ventura County & the Bay Area.

This page explains mailbox lock replacement: what the job includes, what to have ready, honest limits and what sets the price.

Replacing a mailbox lock means removing the old cam lock, with the key, by picking, or by drilling it out, then fitting a new lock with the correct cam and body length and cutting keys. The skill is in matching the right lock to the mailbox format: a 4C cluster box compartment, a 4B+ horizontal panel, or a single wall-mount or curbside box. Who owns the box decides whether we can do it at all.

We dispatch across greater Los Angeles, Ventura County, Silicon Valley and the Bay Area; see the city pages for local detail. The dispatch line at (888) 492-0666 is answered around the clock.

• Opening the compartment when there is no key, by picking or drilling the old lock without damaging the door
• Removal of the old lock and cam, and identification of body length, cam offset and rotation
• Installation of a replacement lock matching the format, with a USPS-approved 4C lock on 4C panels
• Cutting and testing a fresh set of keys
• Bulk replacement across a panel for HOAs and apartment owners, with each compartment numbered and keys tagged
• Replacement of parcel locker locks on privately owned cluster units

• Lost the mailbox key after moving in
• Previous tenant never returned the key
• USPS sealed the mailbox after a key issue
• HOA bulk replacement program
• Tenants in an apartment building need new mailbox keys

• Proof of residency for the compartment, and authorization from the HOA or manager when they own the panel
• The compartment number and whether you have any key at all
• A photo of the lock face and, if the door is open, the back of the lock
• The mailbox type: freestanding cluster unit, lobby wall panel, single wall-mount box, or curbside post box
• How many keys you want

Typically 15-30 minutes for a single compartment. Bulk panel changes, drilled-out locks on older panels, and non-standard cams that need a different lock body take longer.

• Locks on USPS-owned boxes, which includes most curbside cluster units the Postal Service installed on public streets and many older apartment panels, can be replaced only by USPS; the post office will tell you who owns yours
• On privately owned 4C-compliant units the replacement must be a USPS-approved 4C lock; other cam locks will not seat in the door correctly
• The outgoing-mail slot, the carrier's master door and its arrow lock are USPS property and are never serviced
• Older 4B panels and imported boxes may need a lock with a specific cam that must be ordered
• Boxes sealed by USPS are released by USPS, not by a locksmith
• We replace a lock only for the assigned resident or the owner or manager of the panel

The quote depends on the number of compartments, whether the old lock has to be drilled, the lock format (4C, 4B+ or a generic cam lock), the number of keys, and whether the visit is a single box or a bulk panel change.

The dispatcher gives you a range on the phone, and the technician confirms a written quote before any work starts.

Payment is by Cash, Credit Card, Debit Card, Apple Pay and Google Pay, and you receive an itemized receipt listing what was done.

• USPS-approved 4C compartment locks (Florence, Salsbury, National/CompX C9100 series)
• 4B+ horizontal mailbox locks in 1-3/4 inch and 2 inch body lengths (National C8700 series)
• Cam locks for wall-mount and curbside boxes (Hudson, CompX)
• Replacement cylinders for Gibraltar, Mail Boss and Architectural Mailboxes units
• Pedestal cluster unit parcel locker locks

Rekey when the existing locks work smoothly and you only need the old keys to stop working: after a move, a lost key or a tenant change. Replace when the lock is worn, damaged or builder grade on an exterior door you want stronger, or when you want a different function such as a keypad, a connected lock or a restricted keyway. Mixed brands can often be keyed alike by swapping cylinders rather than whole locks.

We dispatch across greater Los Angeles, Ventura County, Silicon Valley and the Bay Area; see the city pages for local detail. For mailbox lock replacement, the city pages list ZIP codes, nearby communities and any local access notes.

Greater Los Angeles includes the San Fernando Valley, the Westside, the South Bay, the San Gabriel Valley, the Gateway Cities, the Santa Clarita Valley and the Antelope Valley. Ventura County includes the Conejo Valley and the coastal cities. In the Bay Area we cover Silicon Valley, the Peninsula and the southern East Bay.

For mailbox lock replacement, tell the dispatcher your address and what is wrong. You get an ETA before anyone is sent, a written quote before any work starts and a receipt when it is done. The line is answered around the clock.

One & Only Locksmith is bonded and insured; a certificate of insurance is available on request.