Suspension Wierdness

[bobiscuit]

Having a strange issue with my 2001 S40 1.9D (145,000 miles)

It feels like I have sideways movement when I go over bumps. It's worst in a bend if I hit a small pothole or a patch of broken road - it feels like a bit of fishtailing.

At 60mph+, going over a bump feels as if the car is twitching to the side rather than just up and down.

And on surface water, all sorts of weirdness happens. The back end feels like it's sliding about slightly (whether it really is - I'm not sure). A bit like aquaplaning, but it happens far more easily than any other car I've driven.

It feels better if I inflate the tyres to 34psi front and 32psi rear instead of the recommended 30/29, but it by no means goes away.
The tyres are Goodyear Excellence all round, about a year old and 6mm+ tread. I actually kept these tyres from my last car (Mondeo V6) and on that car they felt absolutely fine.

I've had my suspension checked over a few times and have been told that it all looks in good condition, except:
1) My drop-links should be replaced (although they look fine to me)
2) My N/S/F strut top mount may be worn

Would either of those things cause the problems I'm having?

[Madhouse]

Sounds like the suggested bits are indeed the rogue areas.

I too some times wonder if my drop links need replacing as I sometimes get a vague feeling mid bend plus I hear the occasional knock too.

As the summer has run out I can't see I'm going to get them sorted, so may well have to wait till the better weather.

I have to say it just doesn't feel 100% but that maybe just me being over picky?

I would be interested to hear any other folks comments or experiences or your outcome bobiscuit

[Dandle]

It could be the things the garage has said but TBH I wouldnt be suprised if it was the tyres if you used them on the mondeo before. Tyres do wear and adapt to the car they are fitted on by putting them onto another car they will now need to wear into the suspension setup of the new vehicle. They are bad enough when you rotate them from front to rear but from a different car they will be much worse, the toe in and camber they used to run on the mondeo will be totally different to that of the S40. If you only wore them down 2mm in a year on a V6 mondeo then it will take along time for them to bed in on the Volvo.

[bobiscuit]

I wondered about that, but I have done about 10,000 miles on the S40 now. The tyres were nearly new when I moved them over (that's why I kept them).

Are the drop-links an easy DIY job or would I need a garage with proper tools incase the bolts were too rusted/siezed?

[modman]

drop links are easy to do your self with a couple of spanners although when your drop links go they usualy start knocking if you take the wheel off try grabbing the drop link and pulling them to see if theirs any play in the ends.

[modman]

not sure were your from but if you were close by ide offer to change them for you its not hard.

[Dandle]

The drop links although worn wouldn't cause the shimmy your experiencing they only control the antiroll bar, they would knock on corners and make the car roll slightly more. They have no control over the side to side stiffness of the trailing arm you wheel is attached to. The rear suspension arms could be at fault as could the trailing arm front bushes but they would really be knocking if they were that bad. My money is still on the tyres. They are a very hard compound and will take along time to settle in, the S/V40 are funny with tyres anyway and fitting part worns isn't going to do it any favours. How much have they worn since you fitted them to the S40 if they were at 6mm when you put them on?

[Clan]

I suggest a 4 wheel align check/ adjust this will show up where the problem lays , maybe the rear suspension arm horizontal tie rod bushes causing the wheel alignment to be out . ...

[TonyM]

Originally Posted by Clan

I suggest a 4 wheel align check/ adjust this will show up where the problem lays , maybe the rear suspension arm horizontal tie rod bushes causing the wheel alignment to be out . ...

I'd agree with this suggestion - I've had similar bizarre happenings in the past and they've been cured by a 4 wheel alignment. I think if the rear wheels are out of alignment they try to steer round bumps instead of going over them.

[bobiscuit]

Thanks for the suggestions.

It does seem like a rear wheel issue. I'm not sure a 4 wheel alignment on its own would help as that's just an alignment of the front wheels, using the rears as a reference (IIRC). Maybe a geometry adjustment if I find somewhere locally to do one...