Chamberlain BC550C Owner's Manual page 8

Assembly
STEP 3 Install the idler pulley
1. 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 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 flathead screwdriver and lift the rail tab until the tab is vertical (90º).
Bolt
Lock Washer
Nut
8
HARDWARE
Nut 3/8"
Rail Tab
Belt
Bolt
Grease Inside
Pulley
Idler Pulley
Trolley Connector
Lock Washer 3/8"
Rail