JLG 40RTS Service Manual - Manual (Page 21)

SECTION 2 - PROCEDURES
3120826 – JLG Sizzor – 2-5
2. Carefully disconnect hydraulic hose from retract port
of cylinder. There will be initial weeping of hydraulic
fluid which can be caught in a suitable container.
After the initial discharge, there should be no further
leakage from the retract port.
3. Activate hydraulic system and activate cylinder
extend function. Check retract port for leakage.
4. If cylinder leakage is 6-8 drops per minute or more,
piston seals are defective and must be replaced. If
cylinder retract port leakage is less than 6-8 drops
per minute, carefully reconnect hose to retract port
and retract cylinder.
5. With cylinder fully retracted, shut down hydraulic
system and carefully disconnect hydraulic hose
from cylinder extend port.
6. Activate motor and activate cylinder retract function.
Check extend port for leakage.
7. If cylinder leakage is 6-8 drops per minute or more,
piston seals are defective and must be replaced. If
extend port leakage is less than 6-8 drops per
minute, carefully reconnect hose to extend port,
then activate cylinder through one complete cycle
and check for leaks.
Cylinders w/Single Counterbalance Valves -
Lift Cylinder
OPERATE ALL FUNCTIONS FROM GROUND CONTROL STATION
ONLY.
1. Using all applicable safety precautions, activate
hydraulic system.
WHEN WORKING ON THE LIFT CYLINDER, RAISE THE PLAT-
FORM COMPLETELY AND SUPPORT THE PLATFORM USING A
SUITABLE OVERHEAD LIFTING DEVICE.
2. Raise platform completely and place a suitable over-
head lifting device or prop approximately 2.5 cm (1
in.) below the platform.
3. Shut down hydraulic system and allow machine to
sit for 10-15 minutes. Carefully remove hydraulic
hoses from cylinder port block.
4. There will be initial weeping of hydraulic fluid, which
can be caught in a suitable container. After the initial
discharge, there should not be any further leakage
from the ports. If leakage continues at a rate of 6-8
drops per minute or more, cylinder repairs must be
made. If the retract port is leaking, the piston seals
are defective and must be replaced. If the extend
port is leaking, the counterbalance valve is defective
and must be replaced.
5. If no repairs are necessary or when repairs have
been made, carefully reconnect hydraulic hoses to
the appropriate ports.
6. Remove lifting device from platform, activate hydrau-
lic system and run cylinder through one complete
cycle to check for leaks.
2.10 CYLINDER REMOVAL AND
INSTALLATION
Lift Cylinder Removal
1. Place the machine on a flat and level surface. Start
the engine/motor and raise the platform. Shut down
the engine/motor and attach a suitable support
device to the platform.
2. Remove the bolts, lock washers, and flat washers
securing the cylinder rod attach pin #1 to the upper
inner arm assembly. Using a suitable brass drift,
drive out the rod end attach pin from the arm assem-
bly.
3. Retract the lift cylinder rod completely.
4. Tag and disconnect, then cap the lift cylinder
hydraulic lines and ports.
5. Remove the bolts, lock washers, and flat washers
securing the barrel end attach pin to the lower arm
assembly. Using a suitable brass drift, drive out the
barrel end attach pin #2 from the arm assembly.
Figure 2-2. Top Lift Cylinder Pin Location