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| Illustration 1 | g00496406 |
Hydraulic Schematic for Machines that have Secondary Steering and Command Control Steering (1) Steering pilot valve (2) Steering wheel (3) Steering quad check valve (4) Left neutralizer valve (5) Manifold (orifice and screen) (6) Orifice (7) Screen (8) Left turn stop (9) Steering crossover relief valve (10) Left steering cylinder (11) Right steering cylinder (12) Steering control valve (13) Shuttle valve (14) Hydraulic line from the hydraulic implement pilot circuit (15) Primary steering pressure switch (16) Check valve (17) Secondary steering pressure switch (18) Check valve (19) Secondary steering pump and electric motor (20) Secondary steering valve (21) Right neutralizer valve (22) Right turn stop (23) Directional spool (24) Pressure reducing valve (25) Signal line (26) Backup relief valve (27) Relief valve for the secondary steering pump (28) Hydraulic line from the hydraulic implement pump (29) Steering pump (30) Relief valve for the case drain for the steering pump (31) Hydraulic line from the pilot/brake pump (32) Pump group (33) Breaker relief valve (34) Steering return line (35) Hydraulic oil tank (AA) Pressure tap for checking pilot pressure for left turns at the steering control valve (BB) Pressure tap for checking neutral pilot pressure at the pilot control valve (CC) Pressure tap for checking pilot pressure for the steering pilot valve (DD) Pressure tap for checking pilot pressure for right turns at the steering control valve (EE) Pressure tap for checking steering pump pressure (FF) Pressure tap for checking signal pressure | |
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| Illustration 2 | g00457379 |
Component Locations for the Secondary Steering System Left Side View (1) Steering pilot valve. (4) Left neutralizer valve. (10) Left steering cylinder. (12) Steering control valve. (19) Secondary steering pump and electric motor. (20) Secondary steering valve. (BB) Pressure tap for checking neutral pilot pressure at the pilot control valve. (CC) Pressure tap for checking supply pressure for the steering pilot valve. | |
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| Illustration 3 | g00457380 |
Component Locations for the Secondary Steering System Right Side View (3) Steering quad check valve. (5) Manifold. (11) Right steering cylinder. (21) Right neutralizer valve. (32) Pump group. (33) Breaker relief valve. (35) Hydraulic oil tank. (AA) Pressure tap for checking pilot pressure for left turns at the steering control valve. (DD) Pressure tap for checking pilot pressure for right turns at the steering control valve. (EE) Pressure tap for checking steering pump pressure. (FF) Pressure tap for checking signal pressure. | |
Note: The secondary steering system is an attachment for these machines. The secondary steering system should only be used if there is a failure of the primary steering system. Additionally, only use the secondary steering system to steer the machine off the road.
The main components of the secondary steering circuit include the following components. Steering pilot valve (1), left steering cylinder (10), right steering cylinder (11), steering control valve (12), secondary steering pump and electric motor (19), secondary steering valve (20) and hydraulic oil tank (35) .
Steering pilot valve (1) is located between the articulated hitch and the front axle. Steering control valve (12) is located on the left side of the machine below the operator's platform. Steering control valve (12) is also located between the operator's cab and the engine.
Secondary steering valve (20) is located on the upper left frame above the secondary steering pump and the electric motor (19).
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| Illustration 4 | g00489463 |
(36) Master action light. (37) Primary steering indicator. (38) Secondary steering indicator. | |
During normal machine operation, check valve (16) is off the seat, while check valve (18) is seated. Check valve (18) prevents pressure oil from primary steering pump (29) from flowing back to secondary steering pump (19) .
If primary steering pump (29) or the engine fails, pressure switch (15) changes contacts. Primary steering pressure switch (15) changes contacts due to low oil pressure in the steering system. Pressure switch (15) sends a signal to the monitoring system. The monitoring system then causes a Warning Category 3 alarm to occur.
| NOTICE |
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The alarm system indicates that the primary steering system has failed. Continuing to operate the machine could result in additional damage to the steering system components. Use the secondary steering system to steer the machine to a safe stop immediately. When the machine comes to a complete stop, turn the start switch key to the OFF position and remove the key. Investigate the cause of the problem before resuming operation. Do NOT use the secondary steering system as a limp-home mode procedure. Do NOT use the secondary steering system for steering the machine when the machine is being towed. |
A Warning Category 3 alerts the operator that engine shutdown should occur as soon as possible. This helps prevent injury to the operator and potential damage to the machine.
A Warning Category 3 causes both master action light (36) and primary steering indicator (37) to turn on. A Warning Category 3 also causes the action alarm to sound. Do not operate the machine until the cause has been corrected.
After a one second delay, the relay for secondary steering pump (19) actuates. At the same time, secondary steering indicator (38) turns on.
Secondary steering pump (19) draws oil from hydraulic oil tank (35). The oil then flows to secondary steering valve (20). This causes check valve (18) to unseat. The oil pressure then causes check valve (16) to seat. This prevents pressure oil from flowing back to steering pump (29). The pressure oil then flows to steering control valve (12) .
The steering oil that is pumped from secondary steering pump (19) causes secondary steering pressure switch (17) to change contacts. Secondary steering pressure switch (17) activates secondary steering indicator (37) .
Note: The machine can be articulated during the following test.
The condition of the secondary steering is tested during engine start-up. During the three second test, secondary steering indicator (38) turns on, and the action alarm sounds. This verifies that the steering system is pressurized.
If the system fails to pass the test during engine start-up, a Warning Category 2 alert indicator turns on. The alert indicator will remain illuminated.
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| Illustration 5 | g00489476 |
(39) Test switch for the secondary steering. | |
The secondary steering system can be manually tested. Test switch (39) for the secondary steering system is located on the upper left console. Test switch (39) is a momentary on, normally open switch.
Push test switch (39) in order to determine if secondary steering pump (19), and secondary steering indicator (37) are operational. When test switch (39) is pushed, secondary steering pump (19) runs. This causes secondary steering indicator (38) to turn on. This also causes the action alarm to sound.
Relief valve (27) is for the secondary steering pump. Relief valve (27) limits the amount of oil pressure in the secondary steering circuit.