HOUSING 8X1924 - Caterpillar

Illustration 1 g06027442
Right Side of Machine
(1) Steering manifold
(2) Front clockwise solenoid
(3) Front counterclockwise solenoid
(4) Pressure tap
(5) Steering shunt solenoid
(6) Counterbalance valvesSteering manifold (1) is mounted to the bulkhead under the hydraulic tank. The right side compartment door provides access to the steering manifold.Steering manifold (1) contains components used to control the steering system. Pressure tap (4) on the manifold is used to check steering pump supply pressure.Note: The machine shown is not equipped with the optional drum offset system. In this case, the manifold is slightly smaller and does not contain the solenoid valves and counterbalance valves for the drum offset system.Note: Refer to "Drum Offset System" for additional information about components and controls for the drum offset system.The steering control valve is controlled by the machine ECM. The steering is controlled by two solenoids. Front clockwise solenoid (2) causes the machine to turn right. Front counterclockwise solenoid (3) causes the machine to turn left. The steering control valves direct oil to the head or rod end of the steering cylinder depending on desired direction of turn and seat position.Steering shunt valve (5) enables and disables the steering system. When the shunt solenoid is energized, the shunt valve is closed and oil from the steering pump is routed to the steering control valve. In this case, the steering system is enabled. When the shunt solenoid is not energized, the shunt valve is open and oil from the pump is sent directly to the charge filter. In this case, the steering system is disabled.Counterbalance valves (6) ensure that the steering cylinder will not move unless pressurized oil is in one end of the cylinder. When supply oil is made available to one end of the cylinder, pressure shifts the counterbalance valve on the other end of the cylinder. The shifted counterbalance valve opens the other end of the steering cylinder to a passage leading to the charge filter.A check valve (not shown) is installed in parallel with each counterbalance valve. The check valve prevents hydraulic oil from flowing out of the steering cylinder unless the corresponding counterbalance valve is open.When the hydraulic oil temperature is less than 20 °C (68 °F), the machine ECM energizes the warm-up solenoid (not shown). In this case, the warm-up valve directs supply pressure to a network of shuttle valves that monitor the system demand pressures. At the same time, the spool of the flow control valve closes. When the spool closes, system pressure increases until the pressure reaches the setpoint of the relief valve at 19300 kPa (2799 psi). The flow of hydraulic oil through the relief valve rapidly heats the hydraulic oil.