TM 5-3805-291-23-2
BRAKE ACCUMULATOR MAINTENANCE - CONTINUED
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CHARGING
WARN I N G
DO NOT disconnect or remove any hydraulic systemline or fitting unless engine is shut down and
hydraulic system pressure has been relieved. Tighten all connections before applying pressure. Escaping
hydraulic fluid under pressure can penetrate the skin, causing injury to personnel.
At operating temperature, hydraulic oil is hot. Alow hydraulic oil to cool before disconnecting any
hydraulic lines. Failure to follow this warning may result in injury to personnel.
The accumulator is filled with dry nitrogen. DO NOT loosen or remove the valve or cap from the top of
the accumulator. Failure to follow this warning may result in injury to personnel.
N OT E
To ensure nitrogen charge is correct, each brake accumulator piston must be at bottom of accumulator
cylinder. Nitrogen gas pressure varies with temperature. To obtain the most accurate nitrogen charge,
temperature of each accumulator must be identical to air temperature around accumulators.
The pressures in Table 1 are for ambient air temperature ranging from 20F to 120F (-7C to 49C).
Adjust pressure for other ambient conditions, as required.
1.
Stop engine.
2.
Press brake pedal repeatedly until there is no brake pressure.
3.
Use nitrogen gas charging system to determine pressures when charging accumulators.
Table 1. Accumulator Precharge Temperature/Pressure
Relationship for 1,000 psi (6,900 kPa) Service Brake Accumulators.
Temperature
Pressure
20F (-7C)
907 psi (6,250 kPa)
30F (-1C)
926 psi (6,380 kPa)
40F (4C)
945 psi (6,510 kPa)
50F (10C)
964 psi (6,640 kPa)
60F (16C)
983 psi (6,770 kPa)
70F (21C)
1,000 psi (6,900 kPa)
80F (27C)
1,020 psi (7,030 kPa)
90F (32C)
1,039 psi (7,160 kPa)
100F (38C)
1,058 psi (7,290 kPa)
110F (43C)
1,077 psi (7,420 kPa)
120F (49C)
1,096 psi (7,550 kPa)
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