MAINTENANCE
7-10
HYDRAULIC SYSTEM
IMPORTANT: Hydraulic equipment such as hydraulic
pumps, control valves, and relief valves
have been adjusted at the factory. Do not
attempt to disassemble or turn the ad-
justing screws, as they are very difficult
to readjust.
Consult your authorized dealer if any
trouble should occur.
1. Oil from the main and swing pumps flows through the
control valves to the cylinders and motors. Most re-
turn oil from the control valves flows back to the hy-
draulic oil tank via the full-flow filters; a small amount
returns via oil coolers directly. High pressure strainers
are provided in the pump delivery lines between the
pumps (excluding the swing pumps) and control
valves.
2. The pilot valves actuated by the control levers/pedals
send pilot oil from the pilot pumps to the control
valves, moving their spools. This spool movement
routes the pump delivery oil to the cylinders and mo-
tors.
3. Relief valves of sufficient capacity are provided in the
control valves, full-flow filters and the pilot and oil
cooler circuits in order to protect each circuit from ab-
normally high pressure.
4. The excavator is equipped with an accumulator in the
pilot oil line which makes it possible to operate the
front attachment for a few seconds after the engine
has stopped. The accumulator is charged with high
pressure gas; do not attempt to remove or disassem-
ble it, and do not expose the accumulator to flame.
5. The excavator is equipped with an independent oil
cooler and circulation pump for the pump transmis-
sion, which functions to cool pump transmission oil.
Summary of Contents for EX1900-5
Page 1: ......
Page 37: ...SAFETY SIGNS S 29 SS 411 SS 691 SS 442 M18C 01 006 SS 445 M144 07 107 ...
Page 38: ...SAFETY SIGNS S 30 SS 446 SS 723 SS3076117 SS 723 SS 410 SS 723 Loading Shovel ...
Page 39: ...SAFETY SIGNS S 31 SS3091476 M146 01 035 ...
Page 40: ...SAFETY SIGNS S 32 SS 413 M18C 01 007 M18C 01 008 ...
Page 42: ...SAFETY SIGNS S 34 MEMO ...
Page 112: ...DRIVING THE MACHINE 4 12 MEMO ...
Page 140: ...MAINTENANCE 7 8 MEMO ...
Page 146: ...MAINTENANCE 7 14 Hoses Q ty in Use Transmission Oil Cooler Hose 5 2 M18C 07 062 5 ...
Page 156: ...MAINTENANCE 7 24 4 Grouped Grease Fittings 7 Arm Ñ Lubrication M144 07 079 M144 07 005 7 ...
Page 258: ...MAINTENANCE UNDER SPECIAL ENVIRONMENTAL CONDITIONS 9 2 MEMO ...
Page 274: ...TROUBLESHOOTING 11 14 MEMO ...
Page 278: ...SPECIFICATIONS 12 4 MEMO ...