Fasten The Rail To The Motor Unit; Install The Idler Pulley - Craftsman 139.18057 Owner's 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.
Do NOT overtighten.
• 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 12" (30 cm) 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"-20x1-3/4 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 garage door opener,
use ONLY those bolts/fasteners mounted in the top of
the opener.
Cover
Protection
Bolt Hole
Lock Nut
Lock Nut
1/4"-20
Chain and
Cable
Idler
Bolt
3/8" Lock
Washer
HARDWARE SHOWN ACTUAL SIZE
Bolt 1/4"-20 x 1-3/4
9
WARNING
CAUTION
Bolts
"U" Bracket
Bolt
SLIDE RAIL TO STOPS
ON TOP AND SIDES
OF BRACKET
Bolt
Pulley
Washer
Locking Pliers
Trolley
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
Rail
Nut
Bolt
Trolley
Stop Hole
Idler Pulley
Lock Washer 3/8"