JLG 80HX_HX+6_HXER ANSI Service Manual - Manual (Page 84)

SECTION 4 - BOOM & PLATFORM
4-4 – JLG Lift – 3120271
7. Remove the snap rings from the pin which attaches
the telescope cylinder rod end to the boom base
section; use a brass drift to remove the pin.
NOTE: Note and record the number and thickness of any
wear pad shims during wear pad removal.
8. Remove bolts which secure the wear pads to the
inner forward surfaces of the boom base section.
Remove the wear pads from the top, sides and bot-
tom of the boom base section.
9. Using suitable lifting equipment, carefully slide the
assembled mid and fly sections from the base sec-
tion. Place the mid and fly sections on a suitable
trestle.
10. Remove the setscrew which secures the sheave pin
at the aft end of the mid section. Use a suitable
brass drift to remove the pin. Remove the sheave
assembly.
11. Remove the bolts, washers and bar from the trun-
nion pins which secure the cylinder base to the
boom mid section; use a suitable slide hammer to
remove the pins.
WHEN REMOVING THE TELESCOPE CYLINDER FROM THE
BOOM, IT MAY BE NECESSARY AT SOME POINT TO TURN THE
CYL INDE R S LIGHT LY IN ORD ER TO CLE AR AS SEM BLIE S
MOUNTED WITHIN THE BOOM. CARE MUST BE TAKEN TO MOVE
THE CYLINDER SLOWLY FROM THE BOOM AS DAMAGE TO COM-
PONENTS MAY RESULT FROM FORCIBLE IMPACT WITH THESE
ASSEMBLIES.
12. Pull the cylinder partially from the rear of the boom
mid section; secure the cylinder with a suitable sling
and lifting device at approximately the center of
gravity.
13. Carefully remove the telescope cylinder and sheave
assembly. Place the cylinder on a suitable trestle.
14. Remove the bolts and washers from the sheave pin;
remove the pin and the sheave assembly.
NOTE: Note and record the number and thickness of any
wear pad shims during wear pad removal.
15. Remove the bolts which secure the wear pads to the
inner surfaces of the boom mid section; remove the
wear pads from the top, sides and bottom of the mid
section.
16. Remove the bolts and lockwashers which secure the
chain block weldment to the aft end of the fly sec-
tion. Remove the cotter pins from the clevis pins
which secure the extension chain and retraction
chains to the block; remove the clevis pin, washers
and chains from the block.
17. Using suitable lifting equipment, remove the fly sec-
tion from the mid section; place the fly section on a
suitable trestle.
18. Remove the bolts which secure the wear pads to the
aft ends of the fly and mid sections; remove the wear
pads from the boom sections.
Inspection
1. Inspect all sheaves (extend chains, retract chains
and telescope cylinder) for excessive groove wear,
burrs or other damage. Replace the sheaves as nec-
essary.
2. Inspect the extend chain and retract chain sheave
bearings for wear, scoring, or other damage, and for
ovality. Replace the bearings as necessary, ensuring
they are installed flush with the sheave surface.
3. Inspect the extend chain and retract chain sheave
pins for scoring, tapering, ovality and evidence of
correct lubrication. Replace the pins as necessary.
4. Inspect the telescope cylinder sheave pin for taper-
ing, scoring, ovality and evidence of correct lubrica-
tion. Replace the pin as necessary.
5. Inspect the boom pivot pin for wear, scoring or other
damage, and for tapering or ovality. Replace the pin
as necessary.
6. Inspect the upper lift cylinder attach pin for tapering,
ovality, scoring, wear, or other damage. Ensure the
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 the extend chain attach clevis pins for wear,
scoring, or other damage. Replace the pins as nec-
essary.
9. Inspect the telescope cylinder rod attach pin for
scoring, wear, or other damage. Replace the pin as
necessary.
10. Inspect the inner diameter of the boom pivot bush-
ing for scoring, distortion, wear, or other damage.
Replace the bushing as necessary.
11. Inspect all wear pads for excessive wear or damage.
Replace the pads when worn to within 1/8 inch (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.