Fasten The Door Bracket - Chamberlain LiftMaster Professional Security + 1255LMC-R Owner's Manual

INSTALLATION STEP 11

Fasten the Door Bracket

Follow instructions which apply to your door type
as illustrated below or on the following page.
A horizontal reinforcement brace should be long
enough to be secured to two or three vertical
supports. A vertical reinforcement brace should
cover the height of the top panel.
Figure 1 shows one piece of angle iron as the
horizontal brace. For the vertical brace, 2 pieces of
angle iron are used to create a U-shaped support.
The best solution is to check with your garage door
manufacturer for an opener installation door
reinforcement kit.
NOTE: Many door reinforcement kits provide for
direct attachment of the clevis pin and door arm. In
this case you will not need the door bracket; proceed
to Step 12.
SECTIONAL DOORS
1. Center the door bracket on the previously marked
vertical centerline used for the header bracket
installation. Note correct UP placement, as
stamped inside the bracket.
2. Position the top edge of the bracket 2"-4" below
the top edge of the door, OR directly below any
structural support across the top of the door.
3. Mark, drill holes and install as follows, depending
on your door's construction:
Metal or light weight doors using a vertical angle
iron brace between the door panel support and
the door bracket:
• Drill 3/16" fastening holes. Secure the door bracket
using the two 1/4"-14x5/8" self-threading screws.
(Figure 2A)
• Alternately, use two 5/16" bolts, lock washers and
nuts (not provided). (Figure 2B)
Metal, insulated or light weight factory reinforced
doors:
• Drill 3/16" fastening holes. Secure the door bracket
using the self-threading screws (Figure 3).
Wood Doors:
• Use top and bottom or side to side door bracket
holes. Drill 5/16" holes through the door and
secure bracket with 5/16"x2" carriage bolts, lock
washers and nuts (not provided) (Figure 4).
NOTE: The 1/4"-14x5/8"
self-threading screws are
not intended for use on
wood doors.
HARDWARE
SHOWN
ACTUAL SIZE
Self-Threading
Screw
1/4"-14x5/8"
20
WARNING
CAUTION
To prevent damage to garage door, reinforce inside of
door with angle iron both vertically and horizontally.
Header
Bracket
Door
Bracket
Location
Vertical
Centerline
Figure 1
Vertical
Reinforcement
Vertical
Centerline
UP
Door
Bracket
Self-Threading
Screw
1/4"-14x5/8"
Figure 2A
Vertical
Centerline
UP
Self-Threading
Screw
1/4"-14x5/8"
Figure 3
HORIZONTAL AND VERTICAL
REINFORCEMENT IS NEEDED
FOR LIGHTWEIGHT GARAGE
DOORS (FIBERGLASS,
ALUMINUM, STEEL, DOORS
WITH GLASS PANEL, ETC).
(NOT PROVIDED)
Vertical
Reinforcement
(Not Provided)
Vertical
Centerline
Bolt
5/16"-18x2"
Door
Bracket
Lock Washer
5/16"
Nut
5/16"-18
Figure 2B
Inside Edge
(Not Provided)
of Door or
Reinforcement Board
Bolt
5/16"x2"
Vertical
Centerline
UP
UP
Figure 4