HARNESS AS 4922072 - Caterpillar

Illustration 1 g00274381
Secondary steering pump
(1) Drive shaft. (2) Idler gear. (3) Inlet port. (4) Drive gear. (5) Pump housing. (6) Outlet port.
The secondary steering pump is a fixed displacement gear pump. Drive shaft (1) turns drive gear (4), which forces idler gear (2) to turn. A seal is formed by the gears against pump housing (5). As the gears turn, oil enters through inlet port (3). 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 (6).
Illustration 2 g02088915
Secondary steering schematic
(7) Check valves. (8) Secondary steering pump. (9) Diverter valve.
Secondary steering pump (8) has four check valves (7). 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 (9). When the machine is moving, the oil always flows to the diverter valve.
Illustration 3 g02089011
Location of the Secondary Steering Pump
(8) Secondary steering pump. (10) Output transfer gear housing. (11) Output shaft.
Secondary steering pump (8) is mounted onto the front of the output transfer gear housing (10) above output shaft (11).If the primary steering pump fails to pump oil or if the engine stops, diverter valve (9) will allow pressure oil from secondary steering pump (8) to flow to the steering control spool.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.