Craftsman 139.53959SRT Owner's Manual page 9

ASSEMBLY STEP 2
Fasten the Rail to the Motor Unit
• Insert a 1/4"-20xl-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 screws 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 _p-_,&
Lock Nut
Bolt 1/4"-20 x 1-3/4 1/4"-20
To avoid serious damageto garage door opener, use
only those screws mounted in the top of the opener.
Screws Motor Unit
_ Sprocket
/
"U" Bracket
Bolt
I Cover
_ rotection
Bolt Hole
SLIDE
ON TOP AND SIDES
OF BRACKET
\ Lock Nut
Hook Spreader
into Back Slots,
then Snap Tab
Into Front Slot
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" 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"-20xl-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.
HARDWARE SHOWN ACTUAL SIZE
Bolt 1/4"-20 x 1-3/4 Lock Nut 1/4"-20 Nut 3/8" Lock Washer 3/8"