Supsension sideways Citroën C5 2009

[bart1989]

My C5 has a strange problem, wich my workshop is not really able to fix.

It's a C5 x7 from 2009 and has the HP supsension. In 2019 at 85000km all the sphers has been changed. Now, the car has driven 155000km.
When I drive over a bad road the whole back of the cars seems unstable. It almost feels like rocking from side to side, even when I drive trough a pothole it feels like a sideways jump. When I was in Germany recently, I drove over the white lines in wet weather and the whole car was shacking from side to side. I was literally moving sideways in my leather seat.

The whole problem has started almost a year ago and my workshop did an alignement 2 times and checked everything on worn bushes. It all seems fine, but the problem still exist.

When driving over a good road everything seems fine. The supsension is super soft and also when I put it on sport is stiffens up, I think that the movement is less on sport.
LDS is good. I drive on original 19' rims with Michelin Pilot Sport 5 tires at 2.6bar. Should be fine..

The workshop thinks that the supsension is to soft and the sphers (4 at the corners) need to be replaced. They putted the car on a shock absorbed test plate and all 4 wheels absorbed it in a different way, no single one gives the same numbers. I think that the sphers from 2019 (IFHS) can't be wrong but have no other clue what the problem can be.

Has anyone a golden tip for me?

Greets from the Netherlands and a kindly worried and most of the time happy Citroën C5 drivers.

Bart

[GiveMeABreak]

Quite possibly the spheres if not originals, especially if the pressures are incorrect or have been 'refilled' which these saucer spheres are not intended to be, unlike the older spherical versions on LHM based vehicles (with the exception of some late Xantias that had slimline spheres at the rear).

Sport mode deactivates the 3 centre spheres on the vehicle so it rides on the 4 corners only which provides the firmer ride, normal mode uses all 7.

[bart1989]

Thanks for your reply!
Off course it's possible that the IFHS (non original) spheres are bad after 4 years, just bad luck.
How would it be possible that the car is wiggleling from side to side on white lines? Maybe an instability in the damping? That the spheres cannot damp the quick movememt?

[GiveMeABreak]

One thing also to remember, that the C5 X7 has an entirely different suspension setup from the earlier C5 and C5 MK II.

The X7 has a multi-link setup at the rear with a complex geometry. You also have an anti roll bar, along with trailing arm, suspension arm, longitudinal arm, links and bushings, so important to check all of these as for a 2009 car these components will be coming on for nearly 15 years old! So I think it needs a thorough check on all these components.

[PaulC5]

I once replaced a steering rack on a Saab 900 and until the tracking was set up at a garage that steered all over the place, especially when wet and on white lines/grates.

[GiveMeABreak]

One thing also to remember, that the C5 X7 has an entirely different suspension setup from the earlier C5 and C5 MK II.

The X7 has a multi-link setup at the rear with a complex geometry. You also have an anti roll bar, along with trailing arm, suspension arm, longitudinal arm, links and bushings, so important to check all of these as for a 2009 car these components will be coming on for nearly 15 years old! So I think it needs a thorough check on all these components.

See this post for a list of the parts for the rear geometry (though the anti-roll bar is not show as that is separate), just to give you an idea:

viewtopic.php?p=691527#p691527