JLG 41AM (3120752) Service Manual - Manual (Page 57)

SECTION 2 - SERVICE PROCEDURES
3120752 – JLG Lift – 2-33
NOTE: The platform mounting section slide pads, are
assembled differently than the slide pads for the
other mast sections. Mast section-5/-6/-7 slide pads
may need to be assembled/disassembled several
times in order to determine the correct shim stock
required for proper fit.
75. Complete the following steps to determine shim
stock thickness required for section-5/-6/-7;
NOTE: Always use the an even amount of shim material
behind slide pads on both sides of the mast rails.
This will keep mast sections centered in rail chan-
nels and prevent any distortion of the section.
a. Use two shim pieces per slide pad, a thick one
and a thin one.
b. Start with a total thickness of approximately
.035" and .075" thick shim stock.
c. Attach shim stock and slide pads to both sides
of mast section-5/-6/-7 using five (5) 1/4"-20UNC
x 1-1/4" long, hex head cap screws per side, with
flatwasher under each bolt head. (Assemble
shim stock and slide pad to mast section rail with
shim stock against rail and slide pad with bev-
eled side out).
PRIOR TO SERIAL# 142920 THE AM MAST INSTALLED TWO
SHORT SLIDE PADS ON EACH SIDE OF THE PLATFORM MOUNT-
ING MAST SECTION. AS OF SERIAL# 142920 A LONGER SINGLE
PAD IS INSTALLED ON EACH SIDE.
ON MACHINES PRIOR TO SERIAL# 142920 THE 41AM MOUNTS
THE (SHORT) UPPER SLIDE PAD IN THE UPPER SET OF SLIDE
PAD MOUNTING HOLES. THE 20AM, 25AM, 30AM AND 36AM
MACHINES MOUNT THE UPPER SLIDE PAD IN THE LOWER SET
OF SLIDE PAD MOUNTING HOLES. (SEE FIGURE 2-5.)
d. Carefully thread the slide pad mounting bolts
with flatwashers through slide pads and shim
stock into threads in mast section-5/-6/-7. Be
certain there are no air gaps between shims,
shim and mast or shim and slide pad when tight-
ened.
NOTE: Mast section-5/-6/-7 into section-4/-5/-6 fit should be
very snug but still be able to be pushed together by
hand. If too tight, remove section-5/-6/-7, disassem-
ble slide pad and reduce thickness of shim stock.
e. Begin sliding top of mast section-5/-6/-7 with
closed rail down engaging the slide pads into
slide pad channels at bottom of mast section-4/-
5/-6’s open rail. Continue to push section-5/-6/-7
into section-4/-5/-6 until BOTTOM ends of mast
sections are even.
f. Check mast section for side play. If play exists
use thicker shims dividing thickness equally
between both sides of mast.
g. When mast slide pads are shimmed properly,
there should be no side to side movement of
slide pad in rail channel. Mast sections should
be very snug in channels but still be able to slide
in channel by hand.
76. Slide mast section-5/-6/-7 to top of section-4/-5/-6.
77. Insert threaded ends of cable assembly (attached to
top of mast section-3/-4/-5) through the cable anchor
plate located on bottom of extended mast section-5/
-6/-7. Loosely thread two (2) 3/8"-16UNC nuts onto
stud threads on each chain. Chains will be adjusted
later in assembly.
78. Slide mast section-5/-6/-7 back into mast section-4/-
5/-6 until bottom ends of masts are even. Check to
make sure cable set attached to top of section-3/-4/-
5 is seating properly in cable sheave wheels
attached to top of mast section-4/-5/-6. (Mast sec-
tions-2, -3, -4 and -5 may need to be restrained to
keep their slide pads from pushing out the bottom of
mast sections-1, -2, -3, -4 and -5).
79. Adjust top and bottom ends of mast sections so they
are all even with each other. At bottom of mast
assembly, thread all chain/cable adjusting nuts on
threaded ends until they are snug against the
anchor plates and all slack is removed from chains
and cables. Check that chains and cables are
seated in their sheave wheels at top of mast assem-
bly.
80. Assemble the latch bar to mast section-5/-6/-7, the
mini covers to the top of each mast section and the
sequencing cables and hardware to the side of the
mast assembly.
Mast assembly should now be complete.