Chamberlain 4142DC Owner's Manual page 10

ASSEMBLY STEP 1
Assemble Rail and Attach the Cable Pulley Bracket
FOR SLIDING AND SWINGING GATES ONLY
To avoid installation difficulties, do not run the garage door
opener until instructed to do so.
1. Align the four rail sections on a flat surface
exactly as shown. Center sections are
interchangeable. Front and back sections are
also interchangeable for ease of assembly.
2. Connect the center sections and the 1/4" lock
nuts to the end sections from the same side,
as shown.
NOTE: If rail is not assembled exactly as
shown, trolley will not travel smoothly along
length of rail or it will hit against nuts.
3. Insert the carriage bolts from the opposite side of the end
sections. Tighten the nuts. When assembled, rail has a front-
to-back position as shown.
4. Position the cable pulley bracket on the front end of the rail as
shown. Fasten securely with the hardware provided.
NOTE: When tightening the bolts be sure to keep bracket
parallel to the rail. Otherwise, the rail may bow when the
opener is operated.
Brace
T-rail
(Center Section)
T-rail
(End Section)
Rail connects to
opener at this end.
HARDWARE
SHOWN ACTUAL SIZE
Hex Bolt
5/16"-18x7/8"
Square Carriage
Bolt Hole
1/4" Lock Nut
Carriage Bolt
1/4"-20x1/2"
10
Carriage Bolts
Lock Nut
1/4"-20x1/2"
1/4"-20
Nut Lock Washer
5/16"-18 5/16"
Cable pulley bracket
attaches to this
end of T-rail.
AWAY FROM
OPENER
T-rail
(End Section)
Hex Bolts
5/16"-18x7/8"
Lock Washer
5/16"
Nut
5/16"
Cable Pulley
Bracket