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Cold ambient temperatures could result in the loss of secondary braking capability due to inadequate hydraulic accumulator nitrogen pre-charge. The loss of the secondary braking system as well as the main hydraulic pressure will result in little or no braking capability and a potential for injury or death. It is recommended to perform a brake accumulator check anytime the machine has been idle for longer than two hours below −25 °C (−13 °F). Refer to Operation and Maintenance Manual before performing any check of the brake accumulator. |
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- Move the engine start switch to the ON position.
- Start the engine and run the engine for one minute in order to increase the accumulator pressure. Alert indicator (1) should turn off. Stop the engine.
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| Illustration 1 | g01401822 |
Note: Alert indicator (1) will illuminate if the brake system is not at the normal operating pressure.
- Apply the service brake pedal and release the service brake pedal in order to decrease the accumulator pressure. Apply the service brake pedal and release the service brake pedal for a minimum of five applications, until alert indicator (1) illuminates.
- If alert indicator (1) illuminates with less than five applications of the service brake pedal, measure the nitrogen precharge pressure of accumulators (2). Consult Systems Operation, Testing and Adjusting, "Brake Accumulator - Test and Charge" for the following information:
- The correct checking procedure
- The correct filling procedure
- The recommended pressure
Your Caterpillar dealer has the appropriate tools for measuring the precharge pressure of the brake accumulators.
Note: Only use dry nitrogen gas to recharge the brake accumulators.
- The correct checking procedure
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| Illustration 2 | g01401825 |
Note: Turn the engine to the OFF position. Check the nitrogen precharge pressure of the accumulators if the machine has been unused for two hours under −32 °C (−26 °F). Consult Systems Operation, Testing and Adjusting, "Brake Accumulator - Test and Charge" for the following information: the correct checking procedure, the correct filling procedure and the recommended pressure