JLG 41AM (3120872) Service Manual - Manual (Page 52)

SECTION 2 - SERVICE PROCEDURES
2-30 – JLG Lift – 3120872
Mast Section 6 - Assembly
(30/41 ft. Masts)
NOTE: Steps 57 thru 69 install section-6 to a seven (7) sec-
tion 30 and 41 ft. mast. If assembling a six (6) sec-
tion 25 or 36 ft. mast, skip to step 70.
60. Locate mast section-6, carefully slide section-6
closed rail into section-5 open rail. Slide sections
together until ends are even.
61. Locate one (1) of the chain anchor plates (one with
threaded holes horizontally aligned to outside edges
of bracket). Attach through outer set of holes in bot-
tom of mast section-6 with two (2) 1/4"-20UNC x 3/4"
long bolts, place a flatwasher under head of each
bolt.
62. Slide mast section-6 out the top of mast section-5 so
the chain anchor plate on bottom of mast section-6
is easily accessible near top end of mast section-5.
Rest the top end of mast section-6 on a support
while performing next step.
63. Insert threaded ends of chain assembly (attached to
top of mast section-4) through the chain anchor
plate located on bottom of extended mast section-6.
Loosely thread two (2) 3/8"-16UNC nuts onto stud
threads on each chain. Chains will be adjusted later
in assembly.
64. Slide mast section-6 back into section-5 except for a
foot or two of length.
65. While mast section-6 is still extended from section-5,
assemble chain sheaves to top of mast section-6 as
follows;
a. Locate remaining sheave pin. Slide two (2) chain
sheave wheels onto sheave pin and center.
b. Place two (2) short spacer tubes on sheave pin,
one on each end of sheave pin to outside of
sheave wheels.
c. Place two (2) sheave pin attach bars, one on
each end of sheave pin to outside of short
spacer tubes.
d. Holding complete chain sheave wheel assem-
bly, slide assembly into top of mast section-6
and align threaded holes in sheave pin attach
bars with holes in mast rails.
e. Attach to top of mast section-6 using two (2) 3/
8"-16UNC x 1/2" long socket head-countersunk-
flathead cap screws, each side. Coat threads
with Loctite #171 and tighten.
NOTE: When sliding mast sections together, be careful not
to scratch or score the anodized finish in the slide
pad channels.
66. Carefully slide mast section-6 back into section-5
until ends are even. Check to make sure chain set
from top of section-4 is seating properly in chain
sheave wheels attached to top of mast section-5.
(Mast sections-3, -4 and -5 may need to be
restrained to keep their slide pads from pushing out
the bottom of mast sections-2, -3 and -4).
67. Insert slide pads into the top end mast rails between
section-5 and -6, (one on each side of the mast),
with beveled surface facing inward towards section-
6.
NOTE: Before fastening and shimming the slide pad on the
top left side of the mast, install a sequence cable
bracket against the mast under the flatwasher.
68. Thread slide pad attaching bolts, (two (2) 1/4"-
20UNC x 3/8" long hex head bolts, place a flat
washer under head of each bolt), through holes in
outside rail, on top of mast section-5 and into the
slide pad inserts. Thread in enough to hold pad in
place.
69. Shim per instructions in step 7, Mast Section 2 -
Assembly.
70. Insert slide pads into the bottom end mast rails
between section-5 and -6, (one on each side of the
mast), with beveled surface facing out towards sec-
tion-5.
71. Thread slide pad attaching bolts, (two (2) 1/4"-
20UNC x 3/8" long hex head bolts, place a flat
washer under head of each bolt), through holes on
inside rail, on bottom end of mast section-4 and into
the slide pad inserts. Thread in enough to hold pad
in place.
72. Shim per instructions in step 7, Mast Section 2 -
Assembly.
Platform Mounting Section - Assy. (All Masts)
NOTE: Reference to mast sections-5/-6/-7 made following is
dependent on which model machine you are servic-
ing since the 20 ft. machines use five (5) mast sec-
tions, the 25 and 36 ft. models use six (6) mast
sections, the 30 and 41 ft. models use seven (7)
mast sections .
73. Locate the remaing mast section-5/-6/-7 (platform
mounting - mast section). Lay mast section on flat
stable surface.
74. Attach the remaining chain anchor plate (one with
threaded holes vertically aligned in center of
bracket). Attach through inner (vertical) set of holes
in bottom of mast section-5/-6/-7 with two (2) 1/4"-
20UNC x 3/4" long bolts, place a flatwasher under
head of each bolt.
NOTE: The platform mounting section slide pads, are
assembled differently than the slide pads for the