Description And Operation of LR3/Disco 3 Power Steering
When the engine is started the power steering pump draws fluid from the reservoir into the low pressure suction line. The
fluid passes through the pump and emerges as pressurised fluid at the outlet port. The attenuated high pressure hose
passes the pressurised fluid to the steering gear valve unit.
If no steering effort is applied, there is minimal restriction within the system and the supply pressure from the pump is low.
Minimal pressure is applied, via the valve unit, to each side of the piston in the hydraulic cylinder and the full flow from the
power steering pump returns to the reservoir via the fluid cooler.
When steering effort is applied in either direction, the return flow of fluid to the reservoir is restricted, causing the supply
pressure from the pump to increase. The pressurised fluid is directed to the applicable side of the piston in the hydraulic
cylinder, via the valve unit, providing the power assistance required to reduce the steering effort. Fluid displaced from the
low pressure side of the cylinder is returned via the valve unit and fluid cooler to the reservoir. The fluid cooler reduces
the fluid temperature which prolongs the life of hoses and seals in the system.
POWER STEERING PUMP
Item Part Number
Description
1
-
Reservoir
2
-
Cooler
3
-
Valve unit
4
-
Steering rack and pinion
5
-
Flow control/pressure relief return
6
-
Flow control/Pressure relief valve
7
-
Output port
8
-
Power steering pump
9
-
Low pressure suction line
