OPTION AR-LINKAGE 3966807 - Caterpillar

Accumulator Charging Valve (5SK743-Up)
Accumulator Charging Valve
(1) Port to brake control valve (rear brakes). (2) Relief valve. (3) Inlet port. (4) Port to brake control valve (front brakes). (5) Return port. (6) Oil pressure switch port. (7) Shuttle valve. (8) Low pressure control valve. (9) High pressure control valve.Oil flows from the pilot pump section of the hydraulic pump into the accumulator charging valve at port (3). Inside the charge valve the oil acts against relief valve (2). The relief valve limits brake oil pressure to 16 550 690 kPa (2400 100 psi).Then the oil flows to accumulator low pressure control valve (8). When oil pressure inside an accumulator drops to 11 710 kPa (1700 psi), this control valve routes oil to shuttle valve (7) and on to the accumulator.Part of the oil flows to accumulator high pressure control valve (9) and out port (6) to the brake oil pressure switch.As accumulator oil pressure rises to 14 470 kPa (2100 psi), oil pressure acting on valve (9) also rises. When the oil pressure causes valve (9) to move, one side of valve (8) is vented back to tank.When oil flows through shuttle valves (7) to the accumulators some of the oil also flows through pilot passages to each side of each shuttle valves. The accumulator charging works the same whether one or both accumulators need recharge.As rear brake accumulator oil pressure rises to 14 470 kPa (2100 psi), the oil pressure also acts against the shuttle valves. The oil pressure rises until it overcomes the valve and causes the valve spool to move and block the flow of oil through port (1). When accumulator pressure drops back to 11 710 kPa (1700 psi), the shuttle valve spool moves the other direction and opens port (1) to allow oil to flow into the accumulator.Both accumulators utilize the same charge valve, but each accumulator is controlled by its own shuttle valve inside the charge valve. The front brake accumulator shuttle valve works the same way.Brake Control Valve (5SK743-Up)
Brake Pedal And Control Valve
(1) Pedal. (2) Brake control valve. (3) Port to rear brake accumulator. (4) Port to front brake accumulator. (5) Port to tank.
Brake Control Valve
(2) Brake control valve. (3) Port to rear brake accumulator. (4) Port to front brake accumulator. (5) Port to tank. (6) Springs. (7) Return port. (8) Passage to rear axle brakes port. (9) Spool. (10) Return port. (11) Passage to front axle brakes port. (12) Spool. (13) Spring.With the engine running, oil flows from the accumulators into brake control valve (2) through ports (3) and (4). When the operator pushes on pedal (1), springs (6) cause spools (9) and (12) to overcome the force of spring (11) and move down.When spool (9) moves down, oil in port (3) flows past the spool and into passage (8). The oil flows through the passage and out the rear brake port into the oil line to the rear service brakes and applies the rear brakes.Spool (9) is on