Negative camber rear suspension
 

Hi All

Any ideas as to why our 08 XC70 AWD has developed pronounced negative camber to the rear wheels over the last few years? A squeak has also returned that was cured about 6 years ago by replacing rear bushes (I don't know which ones but it was a big job) but negative camber wasn't an issue then so not sure if it is related. An inspection on a ramp last night didn't find any play in any bushes. It is now a particular problem because it has just chewed the inside edges off rear tyres in a lot less than 10k miles whereas in the past I was astonished by how long the tyres lasted.

Thanks

If it's both sides and a similar amount then it's unlikely something has been be thus it's more likely to be wear in certain bushes (or more than one set of bushes) along with rear springs getting a bit saggy in their old age? The lower the car sits, the more negative camber it will have. Bushes aren't always easy to judge either, more so if the suspension is weighted or indeed, unweighted.

Assuming nothing is damaged, then you're looking at bushes or ride height control... or both. Also some tyre brands seems more prone to edge wear than others. I'd suggest a four wheel geometry check and if it can be tweaked back in to spec, great but if not then it could just be a combination of a few things adding up as they wear with the miles or age.

I've also got an 08 XC70 AWD and I'm rather astonished by how light its been on it's tyres and I did expect some sort of uneven wear to show as the tyres wore on but nothing as yet and it's now pushing 15k on it's current set. Fairly recent geometry check suggested all was well in that respect through my main trailing arm bushes are on borrowed time now.

Thanks Turbodave - all points that are on my radar but nothing obvious to be seen. Regarding wear, when we first got the car it was on a good but not new set of OE Pirellis and we did another 30k before I began to think about replacing them!

Slightly off topic and I know it's a variable measurement to an extent but I'd be interested to know what the stock ride height should be... say rear wheel centres to arch lip, car empty, 1/2 tank etc. Mine had new front shocks and springs and whilst the rear is all within spec, there are occasions where I think it's slightly down at the back... not much, but just enough to make me wonder how much it's sagged with age over the years compared to new.

Has anyone else experienced this?

Bump ...

Have a look at the Powerflex site. There’s a good image showing all the bushes on the rear suspension. The fact that both sides have gone suggests something has worn out.

Check rear trailing arm bushes. Remove plastic covers, and try to move the trailing arm sideways. Due to rust the rubber will slip, and wheel alignment will be wrong.

Thanks for the replies. The trailing arm bushes do need replacing. This will be the second time (had the car that long!) but I don't remember any negative camber last time. Will let you know how it goes.

Was previously told that the rear suspension couldn't be adjusted because the bolts had seized. However it was only a visual inspection - the nuts are rusted. Are they likely to be seized/should I replace them also?

You won't know until you try and remove them... they might come out fine and the bushes will be in good order, or they'll come out fighting and the bushes will be worn or the bolts will snap and the bushes will be none existent.

I think it needs some ramp time and a geometry check....

Then you'll know for sure.