Craftsman 139.53918D 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 pufley.
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. Connect the
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 FLAT side 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.
DONOT 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.
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
Pin ._
Notch|
Trolley Master
Threaded Link Bar
Shaft
Hole
Retaining
Trolley Slot
Connector
HexScrews
#8x3/8"
Idler Pulley
Belt Cap
Retainer
Motor Unit
Belt Pulley
Plate
10