THEORY OF OPERATION - CONTINUED
BRAKE SYSTEM - CONTINUED
Brake accumulators are located on right-hand side of machine directly behind cab.
There are two brake circuit accumulators, each with a sealed piston. Piston moves upward or downward inside
Chamber has a charge of dry nitrogen gas. Gas is put into accumulator through nitrogen charging valve.
When braking system pressure is higher than accumulator pressure, oil from brake and fan drive pump flows
through port and into chamber. Oil pressure in chamber pushes piston, which compresses dry nitrogen gas. When
accumulators are fully charged, brake charging solenoid valve diverts oil to hydraulic fan and check valve blocks
oil in accumulators.
When brake pedal is pushed, brake system pressure is lower than accumulator pressure and oil in accumulators
flows into brake system to engage brakes.
Brake pressure alert indicator will illuminate when accumulator pressure falls below 1,000 psi (6,895 kPa). Alert
indicator will remain illuminated until accumulator pressure rises above 1,100 psi (6,895 kPa).