JLG 110HX ANSI Service Manual - Manual (Page 36)

SECTION 2 - PROCEDURES
2-12 – JLG Lift – 3120636
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 engine and activate cylinder extend func-
tion. 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 engine and
carefully disconnect hydraulic hose from cylinder
extend port.
6. Activate engine and activate cylinder retract func-
tion. 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, Telescope Cylinder, Extend-A-Reach Cylinder
(if equipped)
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 BOOM TO
HORIZONTAL AND SUPPORT THE BOOM USING A SUITABLE
BOOM PROP OR OVERHEAD LIFTING DEVICE.
2. If working on the lift cylinder, raise boom to horizon-
tal and place a suitable boom prop approximately 1
inch (2.5 cm) below the boom. If working on the tele-
scope cylinder, raise the boom above horizontal and
extend the fly boom approximately 1 foot (30.5 cm).
3. Shut down hydraulic system and allow machine to
sit for 10-15 minutes. Turn ignition switch to ON,
move control switch or lever for applicable cylinder
in each direction, then turn ignition switch to OFF.
This is done to relieve excess pressure in the
hydraulic lines. Carefully remove hydraulic hoses
from appropriate 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
Figure 2-4. Boom Positioning and Support - Cylinder Repair