COVER 6G5277 - Caterpillar

Illustration 1 g03508641
Accumulator Charging Valve (parts removed for clarity)The accumulator charging valve is located on the right side of the machine behind right rear tire. The accumulator charging valve is mounted on a steel plate which is attached to the right rear frame.
Illustration 2 g03508719
(1) Accumulator port for the front brakes. (2) Accumulator port for the rear brakes. (3) Inverse shuttle valve. (4) Pressure relief valve and standby function. (5) Port for the brake oil pressure switch. (6) Outlet to the hydraulic oil tank. (7) Charge control. (8) Flow through port to the hydraulic fan. (9) Inlet from the brake pump. (10) Screen. (11) Orifice for controlling the rate of oil charge to the brake accumulators. (12) Check valve. (13) Spool for cut-in and cut-out pressure.
Illustration 3 g03509257
392-1005 Accumulator Charging Valve (1) Accumulator port for the front brakes. (2) Accumulator port for the rear brakes. (5) Port for the oil pressure switch for the service brakes. (8) Flow through port to the hydraulic oil filter. (9) Inlet from the brake pump. (14) Pressure relief valve and standby function. (15) Access to the main check valve. (16) Plug. (17) Tank port and adjustment screw for cut-in pressure and cut-out pressure.The brake/fan gear pump supplies hydraulic oil to the fan/brake system. The oil first flows to the accumulator charging valve. The accumulator charging valve maintains the pressure in the accumulators at a constant range while the engine is running.The inverse shuttle section of the accumulator charging valve senses the lower pressure of the two accumulator pressures. The oil then flows from the inverse shuttle section of the accumulator charging valve to the low brake oil pressure switch.A spool in the accumulator charging valve then moves in order to allow the hydraulic oil to flow to one accumulator or to both accumulators. In addition, the fan/brake pump supplies pilot oil to the hydraulic fan system. Any excess oil which is not required for these systems is diverted back to the hydraulic oil tank.The accumulator charging valve contains the following internal components. A pressure relief valve, a charge control, a flow control orifice, a spool for cut-in and cut-out pressure and an inverse shuttle valve.The accumulator charging valve controls the flow of oil from the fan/brake pump to the brake accumulators. Pressure relief valve (4) limits the oil pressure that flows from the fan/brake pump to the brake circuit.Charge control (7) regulates the flow of oil to the brake circuit.Note: Charge control (7) contains shims that set the standby pressure of the fan/brake pump. When the pump is at standby pressure, the brake accumulators do not require charging.Check valve (12) prevents oil from flowing through the accumulator charging valve, and back to the fan/brake pump.Spool (13) is for controlling the cut-in and the cut-out pressures for the brake accumulator charging valve. When the oil pressure in the brake circuit reaches the cut-in pressure, spool (13) shifts. The movement of spool (13) causes the spool in flow control valve (7) to shift as well. This movement