VALVE GP-SOLENOID 3517535 - Caterpillar

Pressurized System!Hydraulic accumulators contain gas and oil under high pressure. DO NOT disconnect lines or disassemble any component of a pressurized accumulator. All gas pre-charge must be removed from the accumulator as instructed by the service manual before servicing or disposing of the accumulator or any accumulator component.Failure to follow the instructions and warnings could result in personal injury or death.Only use dry nitrogen gas to recharge accumulators. See your Cat dealer for special equipment and detailed information for accumulator service and charging.
Turn the engine start switch to the ON position. The alert indicator for the brake should come on if the braking system is not at normal operating pressure.
Start the engine. Run the engine at low idle speed until the engine is warm in order to increase the accumulator pressure. The alert indicator should go off.
At low idle engine speed, fully depress the left pedal and release. Repeat this process until hearing the brake charging system recharges the accumulators. When charging, you will hear a slight dip in engine rpm.
Immediately stop the engine and turn the key to the ON position without starting the engine. Fully apply the left pedal and fully release the left pedal at a rate of 1 second on and 1 second off. Count the number of cycles until the alert indicator for brake oil pressure comes on. A minimum of four applications of the left pedal are required for the 924K, 926M, 930K, and 930M. A minimum of three are required for the 938K and 938M.
If the alert indicator comes on before the number of cycles listed in step 4, measure the accumulator pre-charge pressures. Only an authorized Cat dealer can measure the nitrogen gas pressure in the accumulator. Use only dry nitrogen for recharging.