JLG 80HX, Service Maintenance Manual

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SECTION 2 - PROCEDURES
2-20 – JLG Lift – 3120863
10. Attach a suitable sling to the telescope cylinder.
Support the cylinder with an overhead crane or
other suitable lifting device.
11. Remove the two (2) extension chain adjusting nuts
from the eyebolt through the chain adjust assembly.
12. Remove the four (4) bolts and lock washers attach-
ing the chain attach block to the base boom section
and remove the block.
13. Using the lifting equipment, raise the telescope cyl-
inder enough to obtain adequate clearance for
removal of the telescope cylinder rod support
bracket.
14. Remove the cylinder rod support bracket.
15. Attach a suitable lifting device to the extension chain
adjusting eyebolt above the cylinder rod.
NOTE: The extension chain will come out of the boom twice
as far as the telescope cylinder.
16. Using both lifting devices, carefully pull the cylinder
from the boom assembly.
17. As the cylinder is removed from the boom, lay the
extension chain on top of the base boom.
18. Using another lifting device, support the sheave
wheel end of the cylinder and remove the cylinder
from the boom assembly.
19. Carefully lift the cylinder clear of the boom assembly
and lower to the ground or suitably supported work
area.
Telescope Cylinder Installation
1. Using suitable lifting equipment, carefully lower the
cylinder to the boom assembly.
2. Using another lifting device, support the sheave
wheel, or rod end, of the cylinder and install the cyl-
inder into the boom assembly.
3. Slide the cylinder into boom, sliding the extension
chain in place as the cylinder is moving in.
4. Attach a suitable lifting device to the extension chain
adjusting eyebolt.
5. Attach the cylinder rod support bracket to the rod
support block on the telescope cylinder.
6. Install the chain adjust block with four (4) lock-
washer and bolts to the base boom section.
7. Install the two (2) extension chain adjusting nuts that
attach the eyebolt to the chain adjust block.
8. Remove the lifting device from the telescope cylin-
der.
9. Using a suitable brass drift install the trunnion pins
attaching the telescope cylinder to the mid boom
section.
10. Install the capscrews securing the trunnion pins to
each side of the boom. Note that loctite 242 is
required on the capscrew threads.
11. Install the trunnion pin covers on each side of boom.
12. Carefully install the telescope cylinder barrel attach
pin into the base boom.
13. Install the snap rings that retain the telescope cylin-
der pin to the base boom.
14. Remove applicable hydraulic line and port caps and
correctly connect the hydraulic lines to the tele-
scope cylinder. Ensure all hoses are correctly
routed.
15. Install the boom end cover.
16. Activate hydraulic system.
17. Using all applicable safety precautions, operate the
boom functions. Check for correct operation and
hydraulic leaks. Secure as necessary.
18. Cycle (extend/retract) boom several times, then
torque boom chains to 40 ft. lbs. (2.76 Bar). See
Section 2.6, Boom Chains (See Figure 2-2.) for cor-
rect torquing procedure.
19. Check fluid level of hydraulic tank and adjust as nec-
essary.
Boom Lift Cylinder Removal
1. Place the machine on a flat and level surface. Start
the engine and place the boom in a horizontal posi-
tion. Shut down the engine and prop the boom. (See
Figure 2-3.)
2. Remove the hardware retaining the cylinder rod
attach pin to the boom. Using a suitable brass drift,
drive out the cylinder rod attach pin.
3. Using auxiliary power, retract the lift cylinder rod
completely.