Chamberlain 459950 Manual De Usuario

9

•    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.

To avoid SERIOUS damage to garage door opener, use 
ONLY those bolts/fasteners mounted in the top of the 
opener.

•   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.

Bolt 1/4"-20x1-3/4"

Lock Nut
1/4"-20

“U” Bracket

SLIDE RAIL TO  
STOPS ON TOP 
 AND  SIDES
OF BRACKET

Cover 
Protection
Bolt Hole

Lock Nut

Lock 
Nut

Screwdriver

Motor Unit
Belt Pulley

Bolt

Bolt

Bolt

Bolts

Idler
Bolt

Idler
Pulley

Idler
Pulley

Pulley

Lock
Washer
3/8"

Washer

Grease 
 Inside  Pulley

Nut 3/8"

Nut

Trolley 
 Stop  Hole

Trolley 
 Connector

Rail

Bolt 1/4"-20x1-3/4"

Lock Nut 1/4"-20

Lock Washer 3/8"

Nut 3/8"

Idler Bolt