Steering (11.00)

Steering (11.00)

Power Steering (11.02)

The power steering system is hydraulically driven and contains a speed sensitive rack and pinion steering gear (ZF Servotronic II ®). Power assistance is generated by an engine driven vane pump, operating at a constant flow rate.

The level of assistance is controlled electronically via an ECU, which receives a vehicle speed signal from the speedometer. The signal is then converted to a controlled electric current, which is then transmitted to an electro-hydraulic transducer (attached directly to the valve housing). This allows steering efforts to remain lighter at lower speeds to aid parking manoeuvres, whilst at higher speeds, efforts are increased, providing greater directional stability.

Hoses / pipes are used to transmit hydraulic fluid throughout the system. The high-pressure line contains a pressure transducer, which sends an electronic signal to the engine management system. This ensures engine rpm is maintained when the steering system draws higher loads from the engine (i.e. during parking manoeuvres). In order to regulate system temperatures, a wire-wound cooler is incorporated into the return line.

Description

The power steering system uses a rack and pinion type steering gear with servotronic steering assistance. The power steering pump is belt driven and the power steering oil cooler is of a wire bound tube type and is mounted in front of the radiator.

The steering assistance decreases smoothly at a calibrated rate to increase the steering efforts required as vehicle speed increases.

The steering efforts are controlled by the servotronic valve (actuator) position, which in turn is controlled electronically by the servotronic ECU housed in the instrument cluster.

Absolute cleanliness must be observed when replenishing the fluid or dismantling any part of the system. A new power steering reservoir must be installed if the steering gear, pump or fluid cooler is to be replaced. New fluid from a sealed container must be used.