JLG 4017RS Service Manual - Manual (Page 81)

3-41 3614RS, 4017RS
Boom
3.20.2 Lowering Procedure
a. Retract the boom as follows:
1. Remove the cover at the rear corner of the cab.
2. Place a suitable receptacle under the main control valve.
3. Label and disconnect the extend/retract cylinder hoses
(4 & 5) from the main control valve. Install plugs in hoses
to prevent fluid loss. Cap all fittings and openings to
keep dirt and debris from entering the hydraulic system.
Note: Loss of hydraulic oil is limited to the amount trapped
within each hose.
4. Using the hoses and fittings specified, connect the
hoses between the auxiliary hydraulic power supply
and the hoses removed from the main control valve
extend/retract section of the affected machine. Retract
hose (5) is the supply and extend hose (4) is the return.
Connect the hoses in the proper order to ensure that
the cylinder is retracted, not extended.
5. Use the auxiliary power supply to retract the extend/
retract cylinder.
6. Loosen and remove the jumper hoses and reconnect
the extend/retract cylinder hoses.
7. Transfer any hydraulic oil into a suitable, covered
container, and label the container as “Used Oil.” Dispose
of used oil at an approved recycling facility.
8. Clean up all debris, hydraulic fluid, etc., in, on, near and
around the machine.
b. Lower the boom as follows:
1. Place a suitable receptacle under the main control valve.
2. Label and disconnect the lift/lower cylinder hoses
(6 & 7) from the main control valve. Install plugs in hoses
to prevent fluid loss. Cap all fittings and openings to
keep dirt and debris from entering the hydraulic system.
Note: Loss of hydraulic oil is limited to the amount trapped
within each hose.
3. Using the hoses and fittings specified, connect the
hoses between the auxiliary hydraulic power supply
and the hoses removed from the main control valve lift/
lower section of the affected machine. Hose (7) is the
supply (lower) and hose (6) is the return. Connect the
hoses in the proper order to ensure that the boom is
lowered, not raised.
4. Use the auxiliary power supply to lower the boom.
5. Loosen and remove the jumper hoses and reconnect
the lift/lower cylinder hoses.
6. Transfer any hydraulic oil into a suitable, covered
container, and label the container as “Used Oil.” Dispose
of used oil at an approved recycling facility.
7. Clean up all debris, hydraulic fluid, etc., in, on, near and
around the machine.
8. Install the previously removed rear cover. MZ7710
7
4
6
5
VIEW FROM REAR OF CAB