General Information
Electrical Schematic
This is a simplified secondary steering electrical schematic. The schematic is electrically correct. The schematic does not show all the possible harness connectors. A complete Electrical System Schematic can be found in the Service Manual.
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| Illustration 1 | g00104613 |
Electrical Schematic For Secondary Steering System | |
Hydraulic Schematic
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| Illustration 2 | g00104394 |
Steering Schematic (1) Metering pump. (2) Steering control unit. (3) Selector valve. (4) Spool valve. (5) Crossover relief valve. (6) Steering cylinders. (7) Steering control valve. (8) Relief valve. (9) Secondary relief valve. (10) Secondary steering pump. (11) Secondary pump motor. (12) Secondary pressure switch. (13) Secondary steering system. (14) Primary pressure switch. (15) Hydraulic tank. (16) Filter. (17) Primary steering pump. (A) Hydraulic oil line from the implement circuit. (B) Hydraulic oil line from the implement pilot circuit. (C) Hydraulic oil line to the implement pilot circuit. | |
Introduction
If primary steering pump (17) fails, primary pressure switch (14) closes. Pressure switch (14) activates all three warning indications in the cab. The red steering alert indicator flashes to indicate the loss of primary steering pressure. The action lamp flashes and the action alarm sounds. The action lamp and the alarm signal a category three warning. A category three warning means that the machine must be brought to a safe stop immediately. The machine must be shutdown in order to avoid possible loss of machine control, personal injury and/or severe damage to the system or the machine. After a one second delay, the control box activates the relay for the secondary steering motor. Secondary steering motor (11) turns secondary steering pump (10). Secondary steering pump (10) builds up pressure instantly in secondary steering system (13). Secondary pressure opens secondary pressure switch (12). Secondary pressure switch (12) lights the indicator in the cab. The light indicates that secondary steering system (13) has pressure and that the secondary system is functioning properly.
| NOTICE |
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The alarm system indicates that the steering system has failed. When the alarm sounds, bring the machine to a safe stop immediately. Use the secondary steering system only in an emergency. Do NOT use the secondary system as a limp home mode procedure. Do NOT use the secondary system for steering the machine when the machine is being towed. Continuing to operate the machine may result in damage to the system. |
Secondary Steering Pump and Motor
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| Illustration 3 | g00104478 |
Secondary Steering Pump and Motor (1) Secondary steering motor. (2) Inlet port. (3) Secondary steering pump. (4) Ground terminal. (5) Positive terminal. (6) Outlet port. | |
The secondary steering pump group contains motor (1) and pump (3). Secondary steering motor (1) is a 24 Volt DC motor. Motor (1) drives secondary steering pump (3). Motor (1) turns pump (3) in a counterclockwise direction.
Secondary steering pump (3) is a gear pump. Gear pump (3) pulls oil in inlet port (2). The oil is pulled around the gears. The oil exits through outlet port (6). The oil travels through a check valve. The check valve prevents oil from the steering control valve (7 in illustration 2) from entering the secondary steering system (13 in illustration 2) and flowing into the outlet port (6) and back to the tank through inlet port (2) .
Note: The secondary steering pump does not run unless there is a primary steering system failure.
Secondary Relief Valve
The secondary relief valve is built into the secondary steering pump. Oil flow from the secondary steering system is not required if the machine is not being steered. If steering flow is not required, the oil passes over the relief valve.
Secondary Steering Oil Pressure Switch
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| Illustration 4 | g00102189 |
Secondary Steering Oil Pressure Switch (1) Nut. | |
The secondary steering oil pressure switch is usually closed. When the secondary system is activated, the oil pressure opens the secondary steering oil pressure switch. The secondary steering oil pressure switch activates the indicator light in the cab. The light indicates that the secondary steering system is working.
Secondary Steering Valve
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| Illustration 5 | g00104585 |
Secondary Steering Valve Group (1) Cap end. (2) Inlet from secondary steering pump. (3) Inlet from primary steering pump. (4) Secondary steering oil pressure switch port. (5) Primary steering oil pressure switch port. (6) Output to primary steering main control valve. (7) Secondary steering system check valve. (8) Spring. (9) Primary steering system check valve. | |
The secondary valve group contains two check valves (7) and (9). The check valves act as a selector valve. Check valve (7) monitors the secondary steering oil pressure. Check valve (9) monitors the primary steering oil pressure. Check valves (7) and (9) determine the greatest pressure. The greater pressure flows to the steering control valve through output port (6) .