Craftsman 139.53939D Owner's Manual page 10

ASSEMBLY STEP 4
Insta// the Be/t and Attach the Be/t Cap Retainer
1. Pull the belt around the idler pulley and toward the trolley.
Theribbed side must contact the pulley.
2. Hook the trolley connector into the retaining slot on the trolley
as shown.
3. With the trolley against the screwdriver, dispense the
remainder of the belt along the rail length toward the motor
unit and around the sprocket. The sprocket teeth must engage
the belt.
4. Checkto make sure the belt is not twisted and the FLAT side
of the trolley threaded shaft is facing the rail. Connectthe
trolley threaded shaft with the master link, as illustrated:
• Push pins of master link bar through holes in end of belt
and trolley threaded shaft.
• Push master link cap over pins and past pin notches.
• Slide clip-on spring over cap and onto pin notches until both
pins are securely locked in place.
5. Insert the trolley threaded shaft through the hole in the trolley.
Be sure the belt is not twisted and the FLATside of the trolley
threaded shaft faces the rail.
6. Hold the belt at the trolley shaft as you thread the spring nut
by hand onto the shaft until finger tight against the trolley.
DO NOT use any tools.
7. Removethe screwdriver.
8. Position the belt cap retainer over the motor unit sprocket as
shown and fasten to the mounting plate with 8x3/8" hex
screws provided.
Idler Pulley
To avoid possible SERIOUSINJURYto fingers from moving
garage door opener:
• ALWAYS keep hand clear of belt pulley while operating
opener.
• Securely attach belt pulley cover BEFORE operating.
HARDWARESHOWN ACTUALSIZE
Hex Screw 8x3/8"
Spring/Trolley Nut
Master Link
Clip-On Spring
Master Link Cap
Retaining
Trolley Slot
Connector
Pin
Notch|
Trolley Master
Threaded Link Bar
Shaft
Hole
Hex Screws
#8x3/8"
Motor Unit
Belt Pulley
Plate
10