Craftsman 139.53918d - Manual (Page 9)

Fasten the Rail to the Motor Unit
• Insert a 1/4"-20x1 -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.
• Place the “U" bracket, flat side down, on the motor unit
and align the bracket holes with the bolt holes. Fasten
with the previously removed bolts.
• 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
ASSEMBLY STEP 2 CAUTION
To avoid SERIOUS damage to garage door opener, use ONLY
those bolts/fasteners mounted in the top of the opener.
Lock Nut
ASSEMBLY STEP 3
Install the Idler Pulley
• Lay the belt beside the rail, as shown. Grasp the end
with the hooked trolley connector and pass
approximately 12" (30 cm) of belt through the window.
Keep the ribbed side toward the rail, and 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.
Lock Washer
3/8"
---
Trolley
Stop Hole
Grease \
Inside Pulley \
Idler Pulley '
®- Nut 3/8'
I
T rolley
Connector
Idler ^ Lock
Pulley I
Llut