JLG 740A, Service And Maintenance Manual

Page: 228 / 408

SECTION 4 - BOOM & PLATFORM
4-12 – JLG Lift – 3121160
4.5 MAIN BOOM ASSEMBLY
Removal
1. Using a suitable lifting equipment, adequately sup-
port boom assembly weight along entire length.
HYDRAULIC LINES AND PORTS SHOULD BE CAPPED IMMEDI-
ATELY AFTER DISCONNECTING LINES TO AVOID ENTRY OF CON-
TAMINANTS INTO SYSTEM.
2. Tag and disconnect hydraulic lines from telescope
cylinder. Use suitable container to retain any resid-
ual hydraulic fluid. Cap hydraulic lines and ports.
3. Remove hardware securing the main lift cylinder rod
end to the base boom section.
4. Using a suitable brass drift and hammer, remove the
main lift cylinder pin from base boom. Retract the
main lift cylinder by using the auxiliary power switch.
5. Remove the Master Cylinder as follows:
a. Using an adequate supporting device, support
the master cylinder so it doesn’t fall when the
retaining pins are removed.
NOTE: The master cylinder weighs approximately 58.5 lbs.
(26.5 kg).
b. Tag and disconnect hydraulic lines from Master
Cylinder. Use a suitable container to collect any
residual hydraulic fluid. Cap hydraulic lines and
ports.
c. Remove the bolt and keeper pin securing the
master cylinder barrel end pin to the base boom
section. Next, install a 3/8-16 UNC threaded lift-
ing eye into the threaded hole of the pin and pull
pin out.
d. Remove the bolt and keeper pin securing the
master cylinder rod end pin to the upright.
Remove the pin.
NOTE: When installing the master cylinder rod end pin,
insert the keeper hardware pin to prevent the pin
from inserting too far.
6. Remove hardware securing the boom pivot pin to
the upright. Using a suitable brass drift and hammer,
remove the pivot pin from upright.