Daewoo Mega 500-V, Shop Manual

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S0703000
Page 4 Accumulator
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NOTE:
Pre-charge pressure is referred to as the "P1" pressure. The accumulator manufacturer’s
"P1" rated pressure should be stamped or marked on the accumulator’s rating plate.
Annual checks of actual pre-charge pressure should be made by tapping a hydraulic
pressure gauge (and 3-way adapter coupling) into the valve on the bottom of the
accumulator. When hydraulic fluid is pushed out the lower valve opening by the pressure
of the gas charge on the other side of the diaphragm - and there is no counter-pressure
from system oil - the valve button on the bottom of the diaphragm eventually seals off the
lower oil passage. Just after the needle on the gauge reaches its highest point (when there
is 0 bar (0 psi) resistance from hydraulic system pressure) pressure on the gauge will drop
sharply to zero, as the accumulator is completely emptied of oil and the diaphragm button
closes.
Record the highest gauge reading and compare to the "P1" rated pre-charge pressure on the
accumulator manufacturer’s data label. Repeat this test at least once a year to verify proper
functioning of the accumulator.
3. As hydraulic system pressure overcomes accumulator pre-charge pressure, the flexible diaphragm
begins to retract upward.
4. When system oil is at highest working pressure and the accumulator fills to maximum reserve
capacity, the flexible diaphragm is pushed up into the top of the upper chamber.
The highest working pressure is sometimes referred to as the "P3" pressure and can also be
referenced on the manufacturer’s data label on the exterior of the accumulator.
5. If system oil pressure begins to fall off or is momentarily checked or interrupted, the energy stored on
the other side of the diaphragm, in the form of compressed gas, pushes oil back out of the lower
chamber, maintaining oil pressure of the circuit.
6. With minimal system pressure, an equilibrium point may be reached in which accumulator pre-charge
pressure and hydraulic system oil pressure achieve a rough balance. In this condition a minimal
amount of oil is stored in the accumulator.
SPECIFICATIONS
Model Serial Number System
Charge
Pressure
Volume
Mega 130 S/N 0001 - 1003 Pilot
15 kg/cm
2
(210 psi)
320 cc
(19.53 in
3
)
Mega 130 S/N 0001 and Up Brake System
9 kg/cm
2
(130 psi)
500 cc
(30.51 in
3
)
Mega 160 S/N 0001 - 1020 Brake System
8 kg/cm
2
(115 psi)
500 cc
(30.51 in
3
)
Mega 160 S/N 0001 - 1020 Pilot
15 kg/cm
2
(210 psi)
320 cc
(19.53 in
3
)
Mega 160 S/N 1021 and Up Brake System
30 kg/cm
2
(430 psi)
750 cc
(45.77 in
3
)
Mega 200-III S/N 1001 - 1386 Brake System
15 kg/cm
2
(210 psi)
320 cc
(19.53 in
3
)
Mega 200-III S/N 1001 - 1386 Pilot
15 kg/cm
2
(210 psi)
320 cc
(19.53 in
3
)