JLG 15/20MSP Service Manual - Manual (Page 113)

SECTION 5 - MAST COMPONENTS
3121231 – JLG Lift – 5-23
pin keeper. Allow to hang out the top of mast sec-
tion-3 for later assembly.
36. Insert the threaded the ends of chain assembly
(attached to top of mast section-1), into the opening
between mast section-2 and mast section-3. Slide
the threaded ends through the holes in chain anchor
bracket attached at the bottom of mast section-3.
Loosely thread two (2) 3/8"-16UNC nuts onto stud
threads on each chain and remove any slack in the
chains. Chains will be adjusted later in assembly.
37. Assemble chain sheaves (for narrow chain assem-
bly) to top of mast section-3 as follows;
a. Place four (4) of the 1" flat washers onto one of
the remaining sheave pins. Locate two (2) nar-
row chain sheave wheels and slide onto sheave
pin on each side of the flat washers.
b. Slide two (2) short spacer tubes onto sheave
pin, one each end of sheave pin to outside of
sheave wheels.
c. Place two (2) sheave pin support bars, one each
end of sheave pin onto outside of spacer tubes.
Place a roll pin in the slots at each end of the
sheave pins and align with the cutouts in the pin
support bars.
d. Holding complete sheave wheel assembly, slide
assembly into top of mast section-3 and align
threaded holes in sheave pin support bars with
holes in mast rails.
e. Attach to top of mast section-3 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.
38. Slide mast section-3 back into section-2 until ends
are even. Check to make sure chain assembly (wide
chains) are seating properly in chain anchor block
chain sheave wheels attached to mast section-2.
Mast Section 4 - Assembly
NOTE: When sliding mast sections together, be careful not
to scratch or score the anodized finish in the slide
pad channels.
1. Carefully slide mast section-4 into section-3 until
ends are even.
2. Insert slide pads into the top end mast rails between
section-2 and -3, (one on each side of the mast),
with beveled surface facing inward towards section-
3.
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.
3. 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-2 and into the
slide pad inserts. Thread in enough to hold pad in
place.
4. Shim per instructions in step 7, Mast Section 2 -
Assembly.
5. Insert slide pads into the bottom end mast rails
between section-2 and -3, (one on each side of the
mast), with beveled surface facing out towards sec-
tion-2. (Same as Figure 5-7. on page 5-19)
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 on
inside rail, on bottom end of mast section-3 and into
the slide pad inserts. Thread in enough to hold pad
in place.
7. Shim per instructions in step 7, Mast Section 2 -
Assembly.
8. Slide section-4 out the bottom of section-3 approxi-
mately one (1) foot.
9. Locate one (1) of the chain bottom anchor plates
(one with threaded holes horizontally aligned to cen-
ter of bracket). Attach using holes in bottom of mast
section-4 with four (4) 1/4"-20UNC x 3/4" long bolts,
place a flatwasher under head of each bolt.
Mast Section 3 - Sheave Wheel Assembly
1. Support Bar Screws (a) 5. Narrow Washer
2. Pin Support Bars 6. Sheave Pin
3. Wide Spacers 7. Square Keys
4. Sheave Wheel Assys.
Note: (a) Apply Loctite #242 to threads.
1 1
2 2
3
7
6
3 4 4