Install The Trolley; Attach The Rail To The Motor Unit - Chamberlain Security+ 7420 Owner's Manual

ASSEMBLY STEP 2

Install the Trolley

• Attach the trolley threaded shaft to the trolley with
the lock washer and nuts as shown.
• As a temporary stop, insert a screwdriver into the
hole in the front end of the rail.
• Slide the trolley assembly along the rail to the
screwdriver stop.
NOTE: If trolley hits against any nuts on the rail,
the bolts and nuts were attached from the wrong
side and must be repositioned.
Review Assembly Step 1.
ASSEMBLY STEP 3

Attach the Rail to the Motor Unit

To avoid installation difficulties, do not run the
garage door opener until instructed to do so.
• Place the opener on packing material to protect
the cover. For convenience, put a support under
the cable pulley bracket.
• Remove the two washered bolts mounted in top of
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.
Use only these bolts! Use of any other bolts will
cause serious damage to door 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
2" minimum between the trolley and this bolt when
adjusting travel limits (see page 28).
HARDWARE SHOWN ACTUAL SIZE
Hex Bolt
5/16"-18x7/8"
Temporary Stop
Screwdriver
Lock Washer
Nut
5/16"-18 5/16"
Outer Nut
5/16"
Trolley
WARNING
CAUTION
To avoid SERIOUS damage to opener, ONLY use
bolts/fasteners mounted in top of motor unit.
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
9
Inner Nut
Lock
5/16"
Washer
5/16"
Trolley
Threaded
Shaft
HARDWARE SHOWN ACTUAL SIZE
Lock Washer
Nut
5/16"
5/16" -18
USE ONLY THIS
TYPE AND SIZE
BOLT