Fasten The Rail To The Motor Unit And Install The Idler Pulley - Chamberlain 248739M Owner's Manual

ASSEMBLY STEP 2
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, fl at 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.
Lock Nut
1/4"-20
Bolt 1/4"-20x1-3/4"
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.
HARDWARE SHOWN ACTUAL SIZE
Lock Washer 3/8"
HARDWARE SHOWN ACTUAL SIZE
Lock Nut 1/4"-20
To avoid SERIOUS damage to garage door opener,
use ONLY those bolts/fasteners mounted in the top of
the opener.
"U" Bracket
Bolt
Cover
Protection
Bolt Hole
SLIDE RAIL TO STOPS
ON TOP AND SIDES
OF BRACKET
Lock Nut
Idler
Screwdriver
Bolt
Lock
Washer
3/8"
Nut 3/8"
9
Bolts
Bolt
Pulley
Nut
Washer
Trolley
Stop Hole
Grease
Inside Pulley
Idler
Pulley
Nut 3/8"
Trolley
Connector
Bolt 1/4"-20x1-3/4"
Idler Bolt
Motor Unit
Sprocket
Rail
Bolt
Lock
Idler
Nut
Pulley