JLG 600SC_660SJC Service Manual - Manual (Page 68)

SECTION 4 - CAT CHASSIS (PRIOR TO S/N 0300128000)
4-6 – JLG Lift – 3121157
Release Of Hydraulic Pressure From A Single
Hydraulic Circuit
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 a single hydraulic circuit 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 single hydraulic circuit. This will also release any
pressure that might be present in the pilot hydraulic
circuit.
NOTE: If the desired hydraulic circuit that requires service
requires the activation of a switch for operation, acti-
vate the necessary switches for the operation of the
hydraulic circuit.
7. Place the hydraulic activation control lever in the
LOCKED position.
8. Turn the engine start switch to the OFF position.
9. Slowly loosen the filler plug on the hydraulic tank
and release the pressure from the hydraulic tank.
Leave the filler plug loose for a minimum of 45 sec-
onds. This will release the pressure that may be
present in the return hydraulic circuit.
10. Tighten the filler plug on the hydraulic tank to the
specified torque.
11. The pressure in the single hydraulic circuit that
requires service is now released and lines and com-
ponents can be disconnected or removed from that
hydraulic circuit.