LiftMaster 8550 8550 Manual - Page 5

Tighten the Belt - adjustments

Page 5 highlights

2 Tighten the Belt 2.1 By hand, thread the spring trolley nut on the threaded shaft until it is finger tight against the trolley. Do not use any tools. (To motor unit) 2.2 Insert a flathead screwdriver tip into one of the nut ring slots and brace it firmly against the trolley. Spring Trolley Nut Nut ring slot 2.3 Tighten the spring trolley nut with an adjustable wrench or a 7/16" open end wrench about a quarter turn until the spring releases and snaps the nut ring against the trolley. This sets the spring to optimum belt tension. Nut Ring Nut Ring BEFORE 1" (2.5 cm) 5 AFTER RELEASE 1-1/4" (3.18 cm)

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5
2
Tighten the Belt
2.1
By hand, thread the spring trolley nut on the threaded shaft until it is finger tight against
the trolley. Do not use any tools.
Spring Trolley Nut
(To motor unit)
2.2
Insert a flathead screwdriver tip into one of the nut ring slots and brace it firmly against the trolley.
Nut ring
slot
2.3
Tighten the spring trolley nut with an adjustable wrench or a 7/16” open end wrench about a quarter turn until the spring releases and snaps the nut ring against the trolley. This sets the spring to
optimum belttension.
Nut Ring
Nut Ring
AFTER RELEASE
1-1/4"
(3.18 cm)
BEFORE
1"
(2.5 cm)