Steering wheel vibration or wobble

marcus · Post by **marcus** » 11 May 2003, 18:08

I hope you guys will understand but I think that ZX's are pretty similar to Pug 306's so you may be able to advise [:)] The old 1995 306 (manual steering) has a bit of a problem. There is a persistent wobble/vibration in the steering wheel which becomes noticeable at around 50mph and gets worse with increased speed. So far I've done the usual checks; tyre pressures, front wheels balanced and tracking. There has been no change [:(] Plus the car has just passed it's MOT and no strange noises or knocking so I'm thinking that there is no major wear in the suspension?
<b></b><i></i>Can anyone suggest what to look at next? Or better, are there any common concerns with particular bushings etc. in the suspension ?? I've vaguely heard of 'P' bushes, are they a common concern, and if so, what are they ???

algieuk · Post by **algieuk** » 11 May 2003, 18:35

May sound silly, but on my Xantia a similar wobble turned out to be a REAR tyre. I didn't find out until it exhibited a strange wear pattern. Th garage say they suspect the tyre was faulty manufacture and had broken re-inforcements internally.
I would also get your wheel balance checked again....I've known many instances where it wasn't done right.

marcus · Post by **marcus** » 11 May 2003, 20:52

I'll have a look at that. However, in my experience if wheels are out of balance, then you can generally "drive through" the resonance. ie it will occur at a specific speed band of 10-20mph like occuring at 50 but not at 70.
It's not the discs either, they're true and braking is smooth.
Any other people with similar experiences to help solve this one?

blueboy2001 · Post by **blueboy2001** » 11 May 2003, 22:22

It does sound very much like a wheel/tyre problem. When I bought a Xsara in 2001 that had terrible vibration at any speed above 65MPH right up to 100+. It was because the garage hadn't balanced the front wheels properly.
Try swapping the front and rear wheels and tyres over and see if that changes anything. If it changes to a vibration right through the car or disapears then you've found your problem foc.

jeremy · Post by **jeremy** » 12 May 2003, 00:29

Worth looking at the back wheels - is one of them bent? (get someone to drive it slowly while you look - you may be able to see! - or jack it up and spin them and look.
Another place to look is the front drive shafts although I would have thought they would be running smooth at this speed.
Another possibility is a broken or loose engine mount allowing a resonant build up - had this on a Jaguar - felt as though the car was falling apart at 60! Very pleased it only cost £5.00!
Jeremy

Dave Burns · Post by **Dave Burns** » 13 May 2003, 01:30

The "p" bush is the rubber mounting at the rear of the front suspension arm, it attaches the arm to the subframe while allowing it to move for suspension purposes, its aclled a "P" bush because the steel casing into which the rubber is bonded forms the shape of the letter P.
Also found on Xantia, ZX and lots of other PSA's.
Dave

DLM · Post by **DLM** » 13 May 2003, 03:08

I seem to remember reading that at least some 306 front suspension arms include a non-serviceable bush, or at least one which is not available from Pug dealers, whereas on the ZX the same item is freely available. Probably not relevant, but I thought I'd mention it anyway. I'll check out the article if I have time to find it.
David

EDD · Post by **EDD** » 15 May 2003, 03:24

Try swopping rear tyres with front

marcus · Post by **marcus** » 19 May 2003, 22:53

Thanks for the replies. I've had all the wheels rebalanced as well as swapping them - it makes no difference. That brings me back to my original enquiry, "Which are the most common bushes (or other suspension components) that wear so I can thoroughly inspect these?"
All replies would be most useful, especially as I didn't see much on the pug forum!

AndersDK · Post by **AndersDK** » 19 May 2003, 23:25

Marcus -
In general it's quite hard to judge a worn (rubber) bush (or fluidblock), since you need to know play/strain figures. All fluidblocks DO have normal play, when exposed to strain. Usually this is a common MOT test point. These guys know by experience what's acceptable, and what's problematic.
Since no strange sounds appears on the wobble/vibration, it also seems unlikely the cause should be any worn rotating part.
This leaves me to try a totally different track :
An engine problem.
A check on the spark plugs conditions may point to a problem in either fuel or ignition system.
A simple (& cheap) engine compressiontest done by the usual starter motor cranking current graph could also give a hint.
Lumpy engine run worsens under load, i.e. at higher speeds, and rarely shows at idle. I've tried on 2 engines to have a normal idle, and then on increasing load, also increasing vibration. In both instances this was caused by the head gasket tracing between 2 cylinders. The starter engine crank test clearly showed significant difference on cylinder compression, and the plugs were carbonfouled.

algieuk · Post by **algieuk** » 20 May 2003, 03:49

Clutching at straws now, but have you checked your drive shaft inner joints? Had a wobble on my last BX caused by this. The giveaway is that you can usually feel it through the gearstick. On a BX it is easier to diagnose because it becomes more pronounced when teh suspension angle is greater.

marcus · Post by **marcus** » 21 May 2003, 01:21

I hope it isn't an engine related misfire as the vibration/wobble continues if freewheeling.
I'm going to give the whole suspension & steering a really thorough going over as soon as it stops raining (so probably next week [:p]). After that, if nothing shows, I'll substitute the spare for each wheel in turn as there were no concerns when this originally came off the front.
At least it isn't undriveable - but it's hard sticking at the national speed limit on motorways with some good music on to "numb" the vibrations!!