Location of the brake accumulators
(1) Rear brake accumulator
(2) Front brake accumulator
The two brake accumulators are located on the left side of the front frame, in the torque converter compartment.
Service brake accumulator
(3) Nitrogen charging valve
(4) Chamber for nitrogen gas
(7) Pressure oil chamber
(8) Outlet to the retarder control valve and service brake control valve
Each accumulator has a sealed piston (5) that moves up and down inside the bore of the accumulator. Chamber (4) above the piston has a charge of dry nitrogen gas. The dry nitrogen gas is put into the accumulator through nitrogen charging valve (3). The chamber of dry nitrogen gas needs a charge of approximately 5515 kPa (800 psi).
Oil from the accumulator charging valve flows in through port (8). The oil then enters pressure oil chamber (7.) This oil pushes piston (5) up which causes the dry nitrogen gas to compress. When the pressure in the accumulator reaches 14480 ± 345 kPa (2100 ± 50 psi), the accumulator charging valve stops the flow of oil.
When the operator pushes down on the brake pedal or when the retarder is applied, the oil from chamber (7) flows out of port (8). The oil flows from port (8) through the retarder control valve or the service brake control valve in order to apply the service brakes.