JLG 450A_AJ Series II Service Manual - Manual (Page 267)

SECTION 4 - BOOM & PLATFORM
3121180 – JLG Lift – 4-1
SECTION 4. BOOM & PLATFORM
4.1 BOOM MAINTENANCE
DO NOT USE A LIFTING DEVICE TO LIFT BOOMS UNLESS HOLD-
ING VALVES HAVE BEEN REMOVED FIRST. FAILURE TO DO SO
WILL RESULT IN SEVERE DAMAGE TO BOOM.
Removal of Boom Assembly
1. Remove platform and platform support as follows:
a. Disconnect control console electrical cable.
b. Tag and disconnect hydraulic lines to rotate cyl-
inders. Cap hydraulic lines and ports.
c. Use an appropriately rated overhead crane or
suitable lifting device and nylon support straps
to support the platform/support.
NOTE: Properly support cylinder when removing retaining
pin from rod end of level cylinder.
d. Remove bolts and keeper pins from retaining
pins. Remove retaining pins from platform sup-
port using suitable brass drift and hammer.
2. Remove boom from turntable as follows:
a. Disconnect wiring harness from ground control
harness connector.
CAP HYDRAULIC LINES AND PORTS IMMEDIATELY AFTER DIS-
CONNECTING LINES TO PREVENT ENTRY OF CONTAMINANTS
INTO SYSTEM.
b. Tag and disconnect hydraulic lines from boom
to control valve. Use a suitable container to
retain any residual hydraulic fluid. Cap all
hydraulic lines and ports.
c. Using appropriately rated lifting equipment, sup-
port boom weight along entire length.
d. Remove bolts and keeper pins from lift cylinder
pivot pin. Using a suitable brass drift and ham-
mer, remove pivot pin from lower boom.
NOTE: To gain access for removal of pivot pins, it may be
necessary to remove ground control box, hydraulic
and fuel tanks, and counterweight.
e. Remove retaining hardware from level link pivot
pin. Using a suitable brass drift and hammer,
remove pin from level link and turntable.
f. Remove hardware securing lower boom pivot
pin. Using a suitable brass drift and hammer,
remove pin from the turntable.
g. Using all applicable safety precautions, carefully
lift boom assembly clear of turntable and lower
to ground or suitable supported work surface.
Figure 4-1. Location of Components - Boom Removal