Electric power steering failure modes?

Sister's car (with conventional PS) recently developed a very strange feeling on the steering, turned out to be caused by a bent tie-rod: Someone had hit the front wheel while the car was parked. The car still drove in a straight line seemingly normally, but turning was really weird due to the massive change in tracking, especially in the wet.

Electric power steering fault usually manifests as a notchy feel or one way has more assistance than the other, there are places that repair the columns, some even while you wait.

would have thought the power steering failing would be instant,heavy and difficult to steer at all.

It is when it gets complete failure or you unplug it. |Before that it is jerky and odd, apparently the slip ring arrangement is usually the main problem (I have read)

Oooerr?

A mate had a Saab 900 with duff PS and that only worked one way. ;-)

That's the beginnings of what I think I felt MrC.

Oh, thanks.

Cheers, T i m

That's a good explanation of what I have sensed so far. I think if the Mrs was driving it at the time I'm not sure she would have attributed it to the PS but the surface (if at all).

Yup, that's how it felt, like a noisy 'pot' on a radio volume control etc. As you turned the steering wheel the resultant response from the road wheels seemed (very slightly) jerky and non-linear and so slightly affecting the turning radius and the load / feedback on the steering wheel.

I wasn't sure if they used such a thing or it was an rotary / optical encoder of some sort? So if a 'slip ring that applies tension / pressure to something (sensor driving a motor) in reaction to rotation of the wheel?

Cheers, T i m

If you do a search for Steering Angle Sensor, there is a pic of an early VW one that was indeed an optical encoder - with leds and a slotted disc.

ecutesting.com (for example) do a rebuild service and have a page about the problem.

Thanks:

(Assuming it's required) Whilst it's yet another thing to go wrong on this 'free' Meriva (given to me by Mum after Dad died), it looks like it may well be doable costwise and wouldn't need reprogramming etc.

Cheers, T i m

Yes trey do and very good and fast they were when we last used them:)

Thanks for the feedback Tony.

I'm not sure I've noticed the same issue with the steering since posting (or maybe only very slightly) and the bad gearbox linkage is the most impacting. [1]

Cheers, T i m

[1] It looks like the ball / socket on the rod that goes from the gear stick at the gearbox end has failed, allowing too much rotational slack and so not moving the gear arm to the gearbox far enough (and catching a linkage mount as well). Replacement (aftermarket) linkage with a metal tie-rod on it's way. ;-)

Update as of today.

Since the original post the PS has been fine but today we set off for a local trip and there was no PS at all. ;-(

We stayed at our destination for about an hour and when leaving, the PS worked fine (I might have felt a couple of light / heavy spots initially) and it worked on all the subsequent (still local) trips since.

Now again, it had been raining early this morning so I'm beginning to wonder if that is the link?

Maybe if something had got wet, maybe it had dried out in the hour after running the car to temp and leaving it etc?

Do Meriva A's suffer with rainwater (specifically) getting into some electrics / electronics that might affect the PS?

We have been *driving* in some pretty heavy rain and with no issue?

Cheers, T i m