JLG 600SC_660SJC Service Manual User Manual
Page 69
SECTION 4 - CAT CHASSIS (PRIOR TO S/N 0300128000)
3121157
– JLG Lift –
4-7
Release Of Hydraulic Pressure From
Multiple Hydraulic Circuits
PERSONAL INJURY CAN RESULT FROM HYDRAULIC OIL PRES-
SURE AND HOT OIL.
HYDRAULIC OIL PRESSURE CAN REMAIN IN THE HYDRAULIC
SYSTEM AFTER THE ENGINE HAS BEEN STOPPED. SERIOUS
INJURY CAN BE CAUSED IF THIS PRESSURE IS NOT RELEASED
BEFORE ANY SERVICE IS DONE ON THE HYDRAULIC SYSTEM.
MAKE SURE ALL OF THE ATTACHMENTS HAVE BEEN LOWERED
TO THE GROUND, AND THE OIL IS COOL BEFORE REMOVING ANY
COMPONENTS OR LINES. REMOVE THE OIL FILLER CAP ONLY
WHEN THE ENGINE IS STOPPED, AND THE FILLER CAP IS COOL
ENOUGH TO TOUCH WITH YOUR BARE HAND.
CARE MUST BE TAKEN TO ENSURE THAT FLUIDS ARE CON-
TAINED DURING PERFORMANCE OF INSPECTION, MAINTE-
NANCE, TESTING, ADJUSTING AND REPAIR OF THE PRODUCT.
BE PREPARED TO COLLECT THE FLUID WITH SUITABLE CON-
TAINERS BEFORE OPENING ANY COMPARTMENT OR DISASSEM-
BLING ANY COMPONENT CONTAINING FLUIDS.
DISPOSE OF ALL FLUIDS ACCORDING TO LOCAL REGULATIONS
AND MANDATES.
Perform the following Steps in order to release the hydrau-
lic pressure from multiple hydraulic circuits of the main
hydraulic system.
1.
Position the machine on level ground.
2.
Fully retract the stick cylinder rod. Adjust the posi-
tion of the bucket so that the bucket is parallel to the
ground. Lower the boom until the bucket is flat on
the ground.
3.
Shut off the engine.
4.
Turn the engine start switch to the ON position with-
out starting the engine.
5.
Place the hydraulic activation control lever in the
UNLOCKED position.
6.
Move only the joysticks or the pedals of the hydrau-
lic circuit that requires service to the FULL STROKE
positions. This will release the high pressure only in
that hydraulic circuit. This will also release any pres-
sure that might be present in the pilot hydraulic cir-
cuit.
NOTE: If the hydraulic circuit that requires service requires
the activation of a switch for operation, activate the
necessary switches for the operation of the hydraulic
circuit.
7.
Place the hydraulic activation control lever in the
LOCKED position.
8.
Start the engine.
9.
Place the hydraulic activation control lever in the
UNLOCKED position. Do not move any joysticks or
pedals from the NEUTRAL position during this step.
Do not activate any switches during this Step.
10.
Return the hydraulic activation control lever to the
LOCKED position.
11.
Shut off the engine.
12.
Repeat Steps 4 through 11 for each additional
hydraulic circuit that requires service.
13.
After releasing the hydraulic pressure in each of the
desired hydraulic circuits, place the hydraulic activa-
tion control lever in the LOCKED position.
14.
Turn the engine start switch to the OFF position.
15.
Slowly loosen the filler plug on the hydraulic tank
and release the pressure. Leave the filler plug loose
for a minimum of 45 seconds. This will release the
pressure that may be present in the return hydraulic
circuit.
16.
Tighten the filler plug on the hydraulic tank to the
specified torque.
17.
The pressure in the multiple hydraulic circuits that
require service is now released and lines and com-
ponents can be disconnected or removed from
those hydraulic circuits.