Chamberlain B1381C Owner's Manual page 18

Installation
STEP 8 Connect the Door Arm to the Trolley
Installation will vary according to the garage door type. Follow the instructions which apply to your door.
OPTION A - SECTIONAL DOORS
IMPORTANT: The groove on the straight door arm MUST face away from the curved door arm.
1. Close the door. Disconnect the trolley by pulling the emergency release handle.
2. Attach the straight door arm to the outer trolley using the clevis pin. Secure with the ring fastener.
3. Attach the curved door arm to the door bracket using the clevis pin. Secure with the ring fastener.
4. Bring arm sections together. Find two pairs of holes that line up and join sections. Select holes as far apart
as possible to increase door arm rigidity and attach using the bolts, nuts, and lock washers.
5. Pull the emergency release handle toward the garage door opener until the trolley release arm is
horizontal. The trolley will re-engage automatically when the garage door opener is activated.
NOTE: If the holes in the curved door arm and the straight door arm do not align, reverse the straight door arm, select
two holes (as far apart as possible) and attach using bolts, nuts, and lock washers. If the straight door arm is hanging
down too far, you may cut 6" (15 cm) from the solid end.
Clevis Pin 5/16"x1-1/4"
Ring Fastener
Ring Fastener
Lock Washer
Nut
Clevis Pin
5/16"x1-1/4"
18
HARDWARE
Clevis Pin 5/16"x1"
Hex Bolt 5/16"-18x7/8"
Lock Washer
5/16"-18
Nut 5/16"-18
Clevis Pin
5/16"x1"
Hex Bolt
Straight
Door Arm
(Groove
facing out)
Curved
Door Arm