Extend/Retract Cylinder - JLG sky trak mmv Service Manual

3. Use new oiled o-rings and reattach and secure the
hydraulic hoses (right side) or tubes (left side) to the
slave cylinder fittings.
WARNING:
operation in closed areas with inadequate ven-
tilation. Failure to properly ventilate exhaust
fumes can result in death or serious injury.
4. Start and run the engine at approximately one-third
to one-half throttle for about one minute without
moving the vehicle or operating any hydraulic
functions.
WARNING:
under pressure can penetrate the skin, causing
death or serious injury.
5. Inspect for leaks and check the level of the hydraulic
fluid in the reservoir. Shut the engine OFF. Add
hydraulic fluid if required.
6. Conduct a pressure check of the attachment tilt/
slave cylinder hydraulic circuit and bleed the circuit
as outlined in the procedure that follows.
7. Wipe up any hydraulic fluid spillage in, on, near and
around the vehicle, work area and tools.
g. Slave Cylinder Pressure Checking and Circuit
Bleeding
1. Attach a 5000 psi (345 bar) gauge to the main
control valve at the attachment tilt port to test the
attachment tilt and slave cylinder hydraulic system
circuit pressure. The unit is equipped with test
fittings from the factory. Pressure readings should be
3500 psi ±100 psi (241,3 ±7 bar). Refer to Section
9.7, Hydraulic System Testing .
2. With no accessory installed on the quick attach, start
with the lift/lower and attachment tilt cylinders fully
retracted.
Model MMV Rev. 12/04
Avoid prolonged engine
Escaping hydraulic fluid
3. Fully extend the attachment tilt cylinder. Monitor
pressure while fully raising the lift/lower cylinder.
4. Fully retract the attachment tilt cylinder. Monitor
pressure while fully retracting the lift/lower cylinder.
5. Repeat Steps 3-4 five times.
9.14.6

Extend/Retract Cylinder

The extend/retract cylinder (20) is located within the inner
boom.
a. Extend/Retract Cylinder Removal
Procedures for removing the extend/retract cylinder ap-
pear in Section 4.3.2, Inner Boom Replacement .
Hydraulic System
20
MM3790
9.151