Chamberlain AccessMaster M885 Installation Manual page 12

Installation
9 Connect the Door Arm to the Trolley
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. Slide the
outer trolley back (away from the door) about 2" (5 cm).
2. Attach the straight door arm to the outer trolley using the clevis pin. Attach with the ring
fastener.
3. Attach the curved door arm to the door bracket using the clevis pin. Attach with the ring
fastener.
4. Align the straight door arm with the curved door arm. Select two aligned holes (as far apart as
possible) and attach using the bolts, nuts and lock washers.
NOTE: If the holes do not line up, reverse the straight door arm. Select two aligned holes (as far
apart as possible) 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.
Hex Bolt 5/16"-18x7/8"
Nut 5/16"-18
CORRECT
Straight
Door Arm
(Groove
facing
out)
Ring Fastener
Nut 5/16" - 18
Lock
Washer
5/16"
11
HARDWARE
Clevis Pin 5/16"x1-1/4"
Lock Washer 5/16"
Clevis Pin 5/16"x1"
Ring Fastener
INCORRECT
Straight
Curved
Door
Curved
Door
Arm
Door
Arm
Arm
Clevis Pin
5/16"x1"
Hex Bolt
5/16" - 18 x 7/8"
Clevis Pin 5/16"x1-1/4"