Step 11 fasten the door bracket, Sectional doors, Installation step 11 – Chamberlain SECURITY+ 3265M-267 1/2 HP User Manual
Page 19: Fasten the door bracket

19
Fiberglass, aluminum or lightweight steel garage 
doors WILL REQUIRE reinforcement BEFORE 
installation of door bracket. Contact your door 
manufacturer for reinforcement kit.
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" (5-10 cm)
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.
Figure 1
HORIZONTAL AND VERTICAL
REINFORCEMENT IS NEEDED
FOR LIGHTWEIGHT GARAGE
DOORS (FIBERGLASS,
ALUMINUM, STEEL, DOORS
WITH GLASS PANEL, ETC).
(NOT PROVIDED)
Figure 2A
Figure 3
Figure 4
Figure 2B
Door
Bracket
Door
Bracket
Vertical Centerline
of Garage Door
Vertical 
Centerline
of Garage 
Door
Vertical 
Centerline
of Garage 
Door
Vertical Reinforcement
Vertical Reinforcement
Self-Threading
Screw 1/4"-14x5/8"
Self-Threading
Screw 
1/4"-14x5/8"
Bolt
5/16"-18x2"
(Not
Provided)
Bolt 5/16"-18"
(Not Provided)
Nut
5/16"-18
Lock Washer 5/16"
UP
UP
UP
UP
Inside Edge of
Door or
Reinforcement
Board
Vertical
Centerline
of Garage Door
Header
Bracket
Door
Bracket
Location
Vertical
Centerline
of Garage 
Door
HARDWARE SHOWN ACTUAL SIZE
Self-Threading Screw 
1/4"-14x5/8"
