JLG 150HAX ANSI Service Manual - Manual (Page 81)

SECTION 4 - BOOM & PLATFORM
3120679 – JLG Lift – 4-1
SECTION 4. BOOM & PLATFORM
4.1 BOOM MAINTENANCE
Boom Mounted Limit Switches and Valves
NOTE: The numbers on the following descriptions corre-
spond with the numbers in Figure 4-1., Boom
Mounted Limit Switches and Valves Installation.
1. Located inside of turntable at the main boom pivot
pin on the left side - Controls speed of main boom
lift and lower at fully stowed and fully elevated posi-
tions.
2. Outside of Fly Boom - Prevents operating tower
boom lift or lower until the tower telescope is fully
retracted. If tower telescope drifts out when stowed,
tower lift will not operate.
3. Base end of Tower Boom on the bottom side - Pre-
vents Hi speeds of the engine, drive, and 2 speed of
the drive motors when tower boom is raised. Hi
engine will operate when operating tower telescope
and tower lift.
4. On top of Fly Boom - Prevents tower lift down unless
main boom is fully lowered.
5. Inside of the turn tale on the left side - Cam #1 pre-
vents the tower telescope extend function until tower
lift is fully up. Cam #2 prevents main boom lift
unless tower boom is fully up.
Main Boom Removal
1. Shut down machine systems.
NOTE: Main Boom Assembly weighs approximately 6,350
lb. (2,880 kg).
2. Using suitable lifting equipment, adequately support
boom weight along entire length of retracted boom.
HYDRAULIC LINES AND PORTS SHOULD BE CAPPED IMMEDI-
ATELY AFTER DISCONNECTING LINES TO AVOID ENTRY OF CON-
TAMINANTS INTO SYSTEM.
3. Tag and disconnect hydraulic lines that run along
the side of the boom.
4. Remove Bolts and lockwashers attaching upper lift
cylinder rod end attach pin to main boom.
5. Using a slide hammer or similar tool, and taking care
not to damage pin, remove pin from main boom.
6. Using all applicable safety precautions, and only if
necessary, operate main lift down and fully retract
main lift cylinder.
7. Shut down machine systems.
8. Remove bolt and lockwasher securing level link
attach pin to tower boom and remove pin from tower
boom.
9. Remove setscrews securing upper master cylinder
attach pin to level links. Remove pin and remove cyl-
inder rod end from level link.
10. Tag and disconnect all wiring to ground control box.
11. Loosen and remove 4 bolts and lockwashers secur-
ing main boom pivot pin to tower boom.
12. Ensuring that boom is adequately supported and
using a suitable slide hammer, carefully remove
pivot pin from main boom and tower boom. Ensure
that main boom and tower boom are not damaged.
13. Carefully lift main boom assembly clear of tower
boom and lower to ground or suitably supported
work surface.