 | |
| Illustration 1 | g01135949 |
Secondary steering pump (1) Drive shaft. (2) Drive gear (3) Pump housing. | |
 | |
| Illustration 2 | g01135981 |
(4) Inlet port. (5) Outlet port. | |
The secondary steering pump is a fixed displacement gear pump. Drive shaft (1) turns drive gear (2). A seal is formed by the gear against pump housing (3). As the gear turns, oil enters through inlet port (4). The oil is trapped between the teeth and the pump housing. The oil is pulled around the outside of the gears. The oil is then forced out of outlet port (5).
 | |
| Illustration 3 | g01136163 |
Secondary steering schematic (6) Unloader spool (7) Pressure relief valve for the secondary steering system (8) Secondary steering diverter valve (9) Gear pump for the secondary steering system. (10) steering control valves. (11) Check valves. | |
The gear pump for the secondary steering system (9) has two check valves (10). The check valves direct the flow of hydraulic oil that is entering and exiting the secondary steering pump. The oil flows from the secondary steering pump to diverter valve (8). When the machine is moving, the oil always flows to the diverter valve.
If the primary steering pump fails to pump oil or if the engine stops, diverter valve (8) will allow pressure oil from the gear pump for the secondary steering system (9) to flow to the steering control valve (10) .
If the primary steering pump fails to pump oil, the flow switch will activate. This flow switch controls a circuit in the operator compartment which alerts the operator of a failure by sending a warning signal to the cab.