Fasten The Rail To The Motor Unit; Install The Idler Pulley - Chamberlain A1633M Additional Instruction Manual

ASSEMBLY STEP 2

Fasten the Rail to the Motor Unit

• Insert a 1/4"-20 x 1-3/4 bolt into the cover
protection bolt hole on the back end of the rail as
shown. Tighten securely with a 1/4"-20 lock nut.
• Remove the two bolts from the top of the motor
unit.
• Attach spreaders to the U bracket by snapping
them into place.
• Place the U bracket, flat side down, on the motor
unit and align the bracket holes with the screw
holes. Fasten with the previously removed screws.
• Align the rail assembly with the top of the motor
unit. Slide the rail end onto the U-bracket, all the
way to the stops that protrude on the top and sides
of the bracket.
HARDWARE SHOWN ACTUAL SIZE
Bolt 1/4"-20 x 1-3/4
ASSEMBLY STEP 3

Install the Idler Pulley

• Lay the chain/cable beside the rail, as shown.
Grasp the end with the cable loop and pass
approximately 6' of cable through the window.
Allow it to hang until Assembly Step 5.
• Remove the tape from the idler pulley. The inside
center should be pre-greased. If dry, regrease to
ensure proper operation.
• Place the idler pulley into the window as shown.
• Insert the idler bolt from the top through the rail
and pulley. Tighten with a 3/8" lock washer and nut
underneath the rail until the lock washer is
compressed.
• Rotate the pulley to be sure it spins freely.
• Insert a 1/4"-20 x 1-3/4 bolt into the trolley stop
hole in the front of the rail as shown. Tighten
securely with a 1/4"-20 lock nut.
Idler Bolt
To avoid SERIOUS damage to opener, ONLY use bolts
mounted in the top of the motor unit.
Cover
Protection
Bolt Hole
Lock Nut
1/4"-20
Idler
Bolt
3/8" Lock
Washer
HARDWARE SHOWN ACTUAL SIZE
Bolt 1/4"-20 x 1-3/4
4
WARNING
CAUTION
Bolts
"U" Bracket
Bolt
SLIDE RAIL TO STOPS
ON TOP AND SIDES
OF BRACKET
Lock Nut
Chain and
Pulley
Cable
Washer
Trolley
Stop Hole
Grease
Inside Pulley
Idler
Pulley
Cable Loop
3/8" Nut
Lock Nut 1/4"-20 Nut 3/8"
Motor Unit
Sprocket
Hook Spreader
into Back Slots,
then Snap Tab
Into Front Slot
Bolt
Rail
Nut
Bolt
Trolley
Stop Hole
Idler Pulley
Lock Washer 3/8"