The Schlage L283-133 is the OEM mortise lock case for the standard (non-Vandlgard) L Series mortise lock, covering six functions: L9050, L9056, L9060, L9066, L9070, and L9071, documented in the Schlage L Series Service Manual. It ships right hand standard and is field reversible - handing changes without tools or factory modification. The L283-133 is a lock case only. Armor front, strikes, mounting screws, and cylinder are not included and must be ordered separately.

This is the standard lock case. If the installed lock has the Vandlgard (LV prefix) feature, the correct replacement is the L283-601 Vandlgard lock case, not the L283-133. Confirm the installed function code before ordering.

Schlage L283-133: Six Functions in One Lock Case

The L283-133 serves all six functions below because they share the same internal mechanism architecture in the L9000 Series. The lock case houses the latch mechanism, deadlocking auxiliary latch, cam assembly, and related internal components that are common across all six functions. The trim behavior is what differentiates them, not the case.

L9050 Entrance/Office Lock: Latchbolt operated by key from outside or lever from inside. Inside push button on inside trim locks the outside lever. Inside lever always free for egress. One of the most widely specified L Series functions in commercial buildings, schools, and healthcare facilities.

L9056 Entrance/Office Lock with Automatic Unlocking: Functionally identical to the L9050 with the addition of automatic unlocking capability - the lock can be programmed or timed to transition from locked to unlocked at scheduled intervals without manual key operation. The L283-133 case is the mechanical base for this function. This function is NOT available in the Vandlgard (LV) version, which is why L9056 appears in this case but not in the L283-601 Vandlgard case.

L9060 Apartment Entrance Lock: Key controls the outside lever; inside lever always free. Used in hotel corridors, multi-family apartment buildings, and multi-tenant residential properties where outside keyed access is required without inside key egress restriction.

L9066 Store Lock: Outside lever always locked from outside; key required for outside entry at all times; inside lever always free for egress. Used in retail stockrooms, secured storage areas, and restricted access corridors. Like L9056, this function is not available in a Vandlgard version, making the L283-133 the only lock case that covers it.

L9070 Classroom Lock, Exterior Lockdown Only: Outside lever made inoperative by key from the outside only. A person inside the room cannot initiate lockdown without the outside key. Inside lever always free for egress. This is the standard pre-upgrade classroom function installed in most K-12 buildings before current active shooter response protocols became standard.

L9071 Classroom Security Lock, Interior/Exterior Lockdown: Outside lever made inoperative by key from either side - the teacher inside OR the administrator outside can initiate lockdown. Inside lever always free for egress. This is the current standard specification for classroom security hardware and is required by many state and local school security codes for new construction and renovation projects.

Schlage L283-133 vs L283-601: Standard vs Vandlgard

The L283-133 and L283-601 cover the same function group with one critical difference. The L283-601 is the Vandlgard (LV prefix) case - it includes the breakaway lever mechanism that allows the outside lever to rotate freely downward under excessive force while locked, protecting internal components from abuse, vandalism, and forced entry attempts. The L283-133 is the standard (L prefix) case without this feature.

Physically, both cases fit the same mortise pocket and share the same ANSI A156.13 Series 1000, Grade 1 rating and UL 3-hour fire door listing. Replacing an LV function lock case with an L283-133 standard case removes the Vandlgard protection without any other functional change. Replacing an L function case with an L283-601 Vandlgard case adds Vandlgard protection where it did not previously exist. Know which version is installed before ordering.

The L283-133 also covers L9056 and L9066, which have no Vandlgard counterpart in the Schlage L Series catalog. If the installed function is L9056 or L9066, the L283-133 is the only correct replacement case.

SecurityParts stocks OEM Schlage L Series mortise lock cases. Free shipping on orders over $450.