JLG 15VPSP Service Manual - Manual (Page 43)

SECTION 2 - SERVICE PROCEDURES
3120797 – JLG Lift – 2-25
Mast Assembly
(See Figure 2-2.)
MAST SECTION 1 - ASSEMBLY
1. Place mast section-1, rail (open) side up (See Figure
2-1.) on a clean, flat surface (preferably a table or
work bench capable of supporting the weight of the
entire mast assembly). Slide mast out over end of
work surface far enough to allow access to the chain
anchor attach hole near the top of the mast.
2. Locate the two (2) single (wide) chain assemblies
and attach to the large triangular shaped anchor
plate (if not already attached). Lay out the chain/
anchor plate assembly with the anchor plate end
towards top of the mast. (Be certain floor surface is
clean and free of any metal chips or debris which
may stick to lubricated chains).
3. Insert the anchor plate/chain assembly end into the
top of mast section-1 and secure using the large
anchor plate attach pin, spacer, and pin keeper.
MAST SECTION 2 - ASSEMBLY
NOTE: When sliding mast sections together, be careful not
to scratch or score the anodized finish in the slide
pad channels.
4. Locate mast section-2, carefully slide mast section-2
closed rail into section-1 open rail. Slide sections
together until ends are even.
5. Insert slide pads into the slide pad channels at bot-
tom end of mast between section-1 and -2, (one on
each side of the mast), with beveled surface facing
out towards section-1.
6. 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
mast section-2 inside rail, into the slide pad inserts.
Thread in enough to hold pad in place.
7. Shim slide pads using the following steps:
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 mast section.
a. Start with a .036" thick shim and a .075" thick
shim per side at each slide pad.
b. Slide shims into place between slide pad and
mast rail. Tighten the slide pad mounting bolts,
be sure there are no air gaps between shims,
shim and mast or shim and slide pad when tight-
ened.
c. Check mast section for side play. If play exists
add .015" shims dividing the thickness equally
between both sides of mast. Insert shims until
the shims cannot be inserted halfway by hand
with the mast pulled to the opposite side.
d. 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 snug in channels but still be able to slide in
channel by hand.
8. Insert slide pads into the slide pad channels (top of
mast) between section-1 and -2, (one on each side
of the mast), with beveled surface facing in towards
section-2.
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.
9. 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
mast section-1 outside rail (top of mast) and into the
slide pad inserts. Thread in enough to hold pad in
place.
10. Shim per instructions in step 7, Mast Section 2 -
Assembly.
NOTE: If hydraulic cylinder needs to be extended, the pro-
tective caps on the extend and return ports will need
to be temporarily removed. Be careful not to nick or
scour rod surface when extending, also catch any oil
draining out of cylinder to avoid spillage onto work
area.
11. Slide mast section-2 out of mast section-1 approxi-
mately one foot.
12. Locate the hydraulic lift cylinder, slide the lift cylinder
into the closed rail side of mast section-2 with rod
end to top and port end to bottom of mast. Cylinder
should extend out of mast on both ends. Return
tube should be on right side when facing bottom of
mast assembly.
13. Assemble one of the narrow chains sets (#444) and
to the small chain anchor plate using the pins, wash-
ers and cotter keys. Set aside.
14. Locate the chain anchor block and slide it onto the
hydraulic cylinder rod end.
15. Lay out the chain(#444)/anchor plate assembly with
anchor plate end towards mast, (be certain floor sur-
face is clean and free of any metal chip or debris
which may stick to lubricated chains or lay chains in
a clean bucket).
16. Assemble the chain/anchor plate assembly and the
chain anchor block to the cylinder rod end using the
anchor plate/block attach pin and snap ring.