JLG 120-SXJ ANSI Service Manual - Manual (Page 57)

SECTION 4 - BOOM & PLATFORM
3121105 – JLG Lift – 4-5
42. Remove bolts and lockwashers which attach side
wear pads at front of outer mid section and remove
pads and any shims.
43. Remove bolts and lockwashers which attach top
wear pads to front of outer mid section and remove
pads and any shims.
44. Remove bolt, washer and lockwasher attaching fly
section right hand extend chain sheave attach pin to
front of outer mid section.
45. Using a suitable brass drift, carefully drive each
sheave pin from the boom section and remove the
sheave assemblies. Inspect pins, lubrication fittings
and sheave bearings for damage and dirt or foreign
material. Replace components as necessary.
46. Repeat steps (42) and (43) for left hand sheave.
47. Using suitable lifting equipment, carefully slide fly
section clear of outer mid section and lower to
ground or suitably supported work area.
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 in. (3.2 mm)
of insert.
12. Inspect extend and retract chains and chain attach
components 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. If neces-
sary, tap pins into place using a soft headed mallet.
Secure pins using bolts, washers and lockwashers.
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 were
removed during disassembly.
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.