JLG 120HX ANSI Service Manual - Manual (Page 41)

SECTION 2 - PROCEDURES
3120686 – JLG Lift – 2-21
Inspection
1. Inspect all sheaves (extend chains, retract chains
and telescope cylinder) for excessive groove wear,
burrs or other damage. Replace sheaves as neces-
sary.
2. Inspect extend chain and retract chain sheave bear-
ings for wear, scoring, or other damage, and for
ovality. Replace bearings as necessary, ensuring
they are installed flush with sheave surface.
3. Inspect extend chain and retract chain sheave pins
for scoring, tapering, ovality and evidence of correct
lubrication. Replace pins as necessary.
4. Inspect telescope cylinder sheave pin for tapering,
scoring, ovality and evidence of correct lubrication.
Replace pin as necessary.
5. Inspect boom pivot pin for wear, scoring or other
damage, and for tapering or ovality. Replace pin as
necessary.
6. Inspect upper lift cylinder attach pin for tapering,
ovality, scoring, wear, or other damage. Ensure pin
surfaces are protected prior to installation. Replace
pin as necessary.
7. Inspect telescope cylinder trunnion attach pin for
tapering, ovality, scoring, wear, or other damage.
Replace pin as necessary.
8. Inspect extend chain attach clevis pins for wear,
scoring, or other damage. Replace pins as neces-
sary.
9. Inspect telescope cylinder rod attach pin for scoring,
wear, or other damage. Replace pin as necessary.
10. Inspect inner diameter of boom pivot bushing for
scoring, distortion, wear, or other damage. Replace
bushing as necessary.
11. Inspect all wear pads for excessive wear or damage.
Replace pads when worn to within 1/8 inch (3.2 mm)
of insert.
12. Inspect extend and retract chains and chain attach
component for cracks, stretching, distortion, or
other damage. Replace components as necessary.
13. Inspect all threaded components for damage such
as stretching, thread deformation, or twisting.
Replace as necessary.
14. Inspect structural units of boom assembly for bend-
ing, cracking, separation of welds, or other damage.
Replace boom sections as necessary.
Assembly
NOTE: When installing fly section wear pads, install same
number and thickness of shims as were removed
during disassembly.
1. Install upper aft fly section wear pads and shims, as
required, using bolts and lockwashers.
2. Using suitable lifting equipment, carefully slide fly
section into outer mid section.
3. Install fly section extend chain sheaves on front of
outer mid section and install sheave pins.
4. Install lubrication fittings in ends of pins and lubri-
cate sheaves with MPG.
NOTE: When installing outer mid section wear pads, install
same number and thickness of shims, as required,
using bolts and lockwashers.
5. Install outer mid section top front wear pads and
shims, as required, using bolts and lockwashers.
6. Install outer mid section side front wear pads and
shims, as required, using bolts and lockwashers.
7. Install outer mid section bottom front wear pads and
shims, as required, using bolts and lockwashers.
8. Install outer mid section upper aft wear pads and
shims, as required, using bolts and lockwashers.
9. Using suitable lifting equipment, carefully slide
assembled outer mid and fly sections into inner mid
section.
NOTE: When installing inner mid section wear pads, install
same number and thickness of shims as were
removed during disassembly.
10. Install inner mid section top front wear pads and
shims, as required, using bolts and lockwashers.
11. Install inner mid section side front wear pads and
shims, as required, using bolts and lockwashers.
12. Install inner mid section bottom front wear pads and
shims, as required, using bolts, washers and lock-
washers.
13. Install inner mid section upper aft wear pads and
shims, as required, using bolts and lockwashers.
14. Install fly section retract chain adjust block on lower
front end of inner mid section and secure with bolts.
15. Place outer mid section extend chain assembly
along telescope cylinder chain rest with chain adjust
assembly hanging just below cylinder sheave.