824K Wheel Dozer, 825K Soil Compactor and 826K Landfill Compactor Machine Systems Caterpillar

Illustration 1	g03389743
Brake Accumulator (1) Nitrogen charging valve. (2) Accumulator. (3) Nitrogen gas charge. (4) Piston. (5) Seal kit. (6) Pressure oil chamber. (7) Outlet to the service brake control valve.

Piston (4) moves up and down inside the bore of each accumulator (2). Nitrogen gas charge (3) has a charge of approximately 5520 kPa (800 psi). Each accumulator is charged with nitrogen through charging valve (1).

Oil enters pressure oil chamber (6) from the brake pump. The oil reaches the pressure oil chamber through outlet port (7). The oil pushes piston (4) upward. The pressure of the oil compresses the nitrogen gas.

When the pressure in the accumulator reaches approximately 14973 ± 345 kPa (2172 ± 50 psi) for the 834K and the 988K or when the accumulator reaches approximately 14485 ± 345 kPa (2100 ± 50 psi) for the 836K, the supply of oil is stopped. When either brake pedal is pushed, oil from pressure oil chamber (6) flows out of port (7) to the service brake control valve. This action applies the service brakes.