Chamberlain C455 Owner's Manual page 8

Assembly
STEP 3 Install the idler pulley
1. Lay the chain beside the rail, as shown. Grasp the end of the chain and pass approximately
12" (30 cm) of chain 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 near the idler pulley on the front rail section. Use a flat head
screwdriver and lift the rail tab until the tab is vertical (90º).
Bolt
Lock Washer
Nut
8
HARDWARE
Nut 3/8" Lock Washer 3/8"
Rail Tab
Chain
Bolt
Grease Inside
Pulley
Idler Pulley
Rail