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INSTALLATION PROCESS: New PSIN O910 A or B Customer Compartment Lock
(USPS-L-1172C) with Adhesive-Backed Washer on Older Centralized Delivery Equipment
Kit Part Summary :
• PSIN O910A (CW Rotation) or B (CCW) Lock
• Spring clip (included with lock)
• 5/16-24 Nut (included with lock)
• Adhesive-backed washer (included with lock)
Parts from original lock to be saved for later reuse:
• Cam
• Washer or backing plate (if applicable)
Kit Description: For security reasons, the new O910 lock
has a new, unique mounting hole pattern. To work as
intended in the old “Double D” mounting hole used in all
older equipment, an adhesive-backed washer is
mandatory for proper lock installation. In addition, the new
O910 lock is much stronger than previous versions. The
install of the new lock itself includes a new locking nut that
provides much greater strength.
Tools: Screwdrivers (flat blade); vise grip, standard pliers
and/or tongue-and-groove pliers; clean, dry paper or cloth
towel; ratchet w/ ½ inch socket; nutdriver (½ inch) for
NDCBU; Optional: 18” drive extender (for NDCBU installs)
Caution: Make sure you know which style lock is needed
for particular vendor’s equipment being worked on. While
most units will allow either a CW (O910A) or CCW
(O910B) rotating lock, some, like the last few year’s
production of American Locker CBUs (with the hooked
cams), require a CCW rotation. (See the picture on the
right in Step 8.)
1. Open unit to allow access to the backside of the door
with the lock to be replaced. (NOTE: An Arrow Lock key is
required to open unit.) For an NDCBU, use the nutdriver
or ratchet with drive extender to access and loosen the nut
on the lock to be replaced.
2. Remove the existing lock. Note the orientation of the
original lock on the door. Remove the lock’s cam and
save for later reuse. Also, if the original lock used any
type of plate or oversized washer on the back side of the
door, save for later reuse also. If an American Locker
(plastic) CBU, save the original spring clip for reuse.
Lastly, note the direction that the spring clip is removed
3. Clean off the mounting surface for the new adhesive
backed washer with a clean dry towel. (Warning: Without
an attempt to wipe down the washer’s mounting surface,
the washer’s structural adhesive will not perform as
4. Slide the adhesive backed washer over the body of
the lock so that the adhesive side is facing away from the
backside of lock (the washer’s removable liner is
5. Peel off the liner from the washer exposing the
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6. Insert the lock and washer combination from the front
through the lock mounting hole on the door. Apply hand
pressure for a few seconds to assist the bonding process.
Note: Try to align the lock and washer straight to the
original “Double D” hole pattern to ensure that, when
installed, the locked cam will be perpendicular to the side
7a. Slide the spring clip into place through the grooves
closest to the backside of the door. If needed, the pliers or
the vise grip may be used to squeeze the clip into place.
The lock should be tight to the door. (Note: Make sure you
install the clip in the same direction it was originally
installed. Also, if an AmLkr CBU, reuse the original clip.) If
it is too difficult to install the clip, go to 7b.
7b. Shim spacing is needed if the spring clip installed
easily but is not securing the lock to the door adequately or
if the spring clip is too tight to squeeze into place. In this
case, use additional washers on the backside of the door
to fill the gap so that the spring clip can secure the lock to
the door using the back set of grooves.
8. Loosely remount the old lock’s cam on the new lock.
Hand start the new nut provided with the new lock on the
exposed threads. The nut may only allow a partial turn on
the threads by hand. Warning: Make sure to only use the
new nut provided with the new lock. It has a different
thread than the old nut.
9. Tighten down the nut until the cam is completely
seated. Note: It is strongly recommended that while
applying torque to the nut that the cam be prevented from
rotating. This can be done by either holding the cam
approximately as shown or, for some flat doors, clamping a
vise grip to the door directly below the cam to prevent
excessive internal loads on the lock components. Note:
The lock’s key can be installed while the nut is being
tightened but it is not recommended.
10. Check operation of the new lock before closing the
door. If the key inserts and the plug turns without difficulty,
repeat the process with door closed. If this is acceptable,
then close the door and remove the key.
11. Installation process is now completed.
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