the streering wheel rocks back and forth by a couple of inches as i turn ! its like driving a race car fast eg feels like im correcting overstear/understeary all the time altough it does not need drver input to do this the wheel does this on its own any thoughts !

My first thought is tyres.

A bulge in a side wall maybe?


Paul G

I'm thinking tyre's - or something is seriously loose/worn (and may be about to part company with the rest of the car )
Get the jack out and try pulling the wheels around ?

i've got the car lifted and cant see anything wrong wheel seem ok no movement in the bearings or steering rack was wondering about the steering pump/other parts but never had one go down so don't now how to check ! will swap wheels to test them when i get the gearbox back in!( changing the clutchand waiting for parts)

ps is an 54 plate citroen xsara 2.0 HDI (110)

[Edited on 21/9/08 by tomblyth]

I had similar problems with my Yaris a little while ago - the garage couldn't find anything wrong, but suggested that having a different make of tyre on each corner might be the problem - I had replaced tyres over the years and had ended up with a mixed set (though they were all the same size and basic type). A couple of months ago I bought 4 new tyres from black-circles - and the problem went away.

So, from this experience, I'd give all your tyres a good inspection, check all pressures, and also check ride height from side to side - is the wheel arch on the left side the same height of the ground as on the right? Both the same at the back?

If you also have a mix of makes, try swapping them around so that you've got a matching pair on each axle (but be careful if you've got directional tyres).

S slight bulge in the tyre tread will give u this. Look dead on to the wheels on spin in u might see it wobble. You might not see it when looking side on. The tread often lets go of the chords.

Look at the rear most wishbone bush aswell. Common failure on citreons and peugeots. If theyr the same arms as the earlier xsara's they always go.

[Edited on 21/9/08 by Danozeman]

My 406 did something very similar, felt like it was steering itself sometimes. It also did it when throttle on and throttle off.

I didn't spot it straight away but it was this bush:


Description

I was totally gone and it allowed the track to vary. I needed the car very solidy supported and once I pushed and pulled the wheel I could vary the track by about an inch.

Could be that as the symptoms sounds very similar.

no play in the bushes and passed the mot think i'll change the pump it s easy compared to changing the rack!

I think I can fairly safely say it won't be the pump in a million years ---

The correct way to check for free play in cars with power steering is with the engine running --- get somebody to rock the steering wheel while you check the steering joints and rack mountings.

If to check the wishbone ball joints and buses you may help to use a tyre lever.
If you can't see anything get your local mOT test staion to look at putting the car on the MOT swivel slide plates shows up wear in ball joints much easier. --
Don't forget to check the rear !

However ---from your description my guess is it could be your steering rack is knackered --- the rack needs a certain ammount of free play to operate the power steering valve. If the rack mechanism has too much play it can result in fully powered steering with no mechanical feed back through the wheel which is pretty much what you describe.