power steering problem

[12joe340]

When driving along in a straight line (hands off the wheel) the steeling wheel rests pointing abit to the left, and when i turn left it does not seem very responsive, however when i turn to the right it feels ok. The steering wheel does not self correct as well as it should either and also feels heavy to turn, also when i have looked under the car it looks damp on the righthand side of the steering rack.
In the past the power steering fluid level has been below minimum so i took it back to the ford garage and they just topped it up and said it was fine and since then it has stayed at its current level.

Took it to the ford garage this week for a service and mentioned the steering still doesnt feel right and they said everything was fine with it even tho they didnt actually take it on a test drive.

does anyone have any ideas what could be wrong with it ?

[littleredrooster]

If it's a Ka or Fiesta, it could be the rack at the end of its life. They're famous for it. Keep a close eye on the fluid level.

[12joe340]

its an 09 focus

[annodomini2]

12joe340 said:

its an 09 focus

Most are electro-hydraulic (pump's driven by an electric motor, rather than the engine)

2 Things to look at,

1. Is the steering wheel centred when driving in a straight line?

2. If someone else turns the wheel (you can do it when stationary) is the rack leaking?

Definitely sounds like a duff rack.

Pressure in the system is regulated by a valve in the rack which directs flow into the rack cylinder or through a bypass into the header tank on the pump.

Valve is opened by differential torque between the rack and the column.

Flow is regulated by an ECU on the pump unit, via a sensor on the steering column, which tells the ECU if you are turning the wheel and how fast.

Basically you're missing pressure inside the rack, but without flow you won't get pressure.

The garage should be able to measure the pressure in the rack from the ECU in the Pump, it'll probably be different left to right.

Basically my guess would be either the rack is leaking (i.e. no pressure) or the valve is sticking (no flow)

There's an outside chance its a duff sensor, but this should be reported by the ECU on the pump.

If it was the pump you would get no assistance as the sensor is not position based, but velocity.

Just in case you're wondering I wrote the motor control software for the pump.

[12joe340]

ok abit of an update, when i turn the wheel and get near full lock the wheel starts to turn itself in the same direction :s gonna book it into the garage this week as ford must recognise something is wrong with it now