Install The Idler Pulley - Craftsman 139.53990DS Owner's Manual

ASSEMBLY STEP 2
Fasten the Rail to the Motor Unit
1. Insert a 1/4"-20x2-1/2 bolt, washer and spacer into
the cover protection bolt hole on the back end of
the rail as shown. Install lower spacer and washer
then tighten securely with a 1/4"-20 lock nut.
DO NOT overtighten.
2. Remove the bolt and lock nut from the top of the
motor unit.
3. Use the carton to support the front end of the rail.
4. Place the "U" bracket, flat side down onto the motor
unit and align the bracket holes with the bolt holes.
Fasten the "U" bracket with the previously removed
bolt and lock nut; DO NOT use any power tools.
The use of power tools may permanently damage
the garage door opener.
5. Attach spreader to the motor unit with two screws.
To avoid SERIOUSdamage to garage door opener,
use ONLYthose bolts/fasteners mounted in the top of
the opener.
Washer 5/8" _'_
Spacer
Cover
Protection
Bolt Hole
Hex Screws
8-32x7/16"-_-_1_
I
Bolt
Lock Nut
"U" Bracket
Chain
)reader
Motor Unit Sprocket
HARDWARE SHOWN ACTUAL SiZE
Washer 5/8" Lock Nut 1/4"-20
Bolt 1/4"-20x2-1/2"
Spacer
i
Spacer O
Washer 5/8"
Lock Nut _
1/4"-20
ASSEMBLY STEP 3
Install the Idler PuUey
1. Lay the chain/cable beside the rail, as shown.
Grasp the end of the cable and pass approximately
12" (30 cm) of cable through the window. Allow it
to hang until Assembly Step 4.
2. Remove the tape from the idler pulley. The inside
center should be pre-greased. If dry, regrease to
ensure proper operation.
3. Place the idler pulley into the window as shown.
4. 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.
5. Rotate the pulley to be sure it spins freely.
6. Locate the rail tab. The rail tab is between the idler
bolt and the trolley in the front rail section. Use a
flat head screwdriver and lift the rail tab until the
tab is vertical (90°).
Chain and
Cable
._ Grease
_ _ _ __lnside Pulley
Lock t _ Idler
Washer _ Pulley
3/8"
_i Nut 3/8"
Cable Link
HARDWARE SHOWN ACTUAL SIZE
Idler Bolt Nut 3/8" Lock Washer 3/8 '_--f/j
CORRECT
Q
iNCORRECT
Q