Fasten The Rail To The Motor Unit - Chamberlain 4142DC Owner's Manual

ASSEMBLY STEP 3

Fasten the Rail to the Motor Unit

• Place the opener on packing material to protect the cover. For
convenience, put a support under the cable pulley bracket.
• Remove the two 5/16"-18x1/2" washered bolts mounted in the
top of the motor unit.
• Align the holes in the back section of the rail with the holes in
the motor unit.
• Fasten the rail with the two washered bolts previously removed.
Tighten securely. Remember to use only these bolts! Any other
bolts will cause serious damage to the opener.
• Insert a 5/16"-18x7/8" hex bolt into the cover protection bolt
hole in the rail as shown. Tighten securely with a 5/16" lock
washer and nut.
NOTE: This bolt prevents trolley over-travel. Keep a 25 mm
minimum between the trolley and this bolt when adjusting travel
limits (see page 29).
HARDWARE SHOWN ACTUAL SIZE
Hex Bolt
5/16"-18x7/8"
Lock Washer
Nut
5/16"
5/16"-18
To avoid SERIOUS damage to garage door opener, use ONLY
those bolts/fasteners mounted in the top of the opener.
Washered Bolt
5/16"-18x1/2"
Hex Bolt
5/16"-18x7/8"
Cover
Protection
Bolt Hole
Rail
(Back
Section)
Lock Washer
5/16"
Nut
5/16"-18
12
USE ONLY THIS
TYPE AND SIZE
BOLT