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Gas Pressure of Pressure Accumulator, Checking

Gas pressure of pressure accumulator; checking

Note

- gas pressure of new accumulator 78-82 bar (1131-1189 psi) at 20°C (68°F)
- minimum gas pressure 30 bar (435 psi) at 20°C (68°F)

Work sequence

- with engine not running, press brake pedal about 20 times to reduce system pressure




- disconnect wire on warning light switch and remove switch (arrow)




- attach pressure gauge with hollow bolt and copper washers to brake servo unit


NOTE: Attach thick copper washer between brake servo unit and banjo fitting and thin copper washer between hollow bolt and banjo fitting

- start engine and let idle until pressure gauge reads approx. 140 bar (2030 psi)
- turn ignition OFF
- pump brake pedal until pressure drops slowly
- pressure reading at which gauge pointer drops down rapidly to "0" is gas pressure of pressure accumulator
- if pressure is lower than 30 bar (435 psi) accumulator must be replaced

- remove pressure gauge
- install brake light warning switch and reconnect wire connector
- check all connections for leaks