Xantia suspension hard despite new spheres

[Jogador]

Hi!

I did the introductions elsewhere, so I'll cut to the chase here.

My beloved 1998 Mk2 Xantia SX (normal 6-sphere layout, no HA) has developed a very bouncy ride when driving on short bumps or speed humps, regardless of the speed I'm doing. I am aware that hydraulic suspension is not ideal for short bumps, as the reaction time is longer than with conventional springs/dampers, but I distinctly remember it being much better when I first bought it. This problem has started a few months ago, and is really buggin' me, as the car is without fault otherwise.

I've just had the spheres renewed, changed the LHM and cleaned the filters for the second time in a year (by a mechanic specialised in old hydro citroens), the height regulators were cleaned and well greased, the system was bled thoroughly, but the problem remains.

Any ideas as to what could be wrong?

I seem to remember reading about it being a problem with the ant-sink valve, but I found no explanation on this.

Any help will be greatly appreciated

[Xaccers]

Check ride height

[Mandrake]

My beloved 1998 Mk2 Xantia SX (normal 6-sphere layout, no HA) has developed a very bouncy ride when driving on short bumps or speed humps, regardless of the speed I'm doing. I am aware that hydraulic suspension is not ideal for short bumps, as the reaction time is longer than with conventional springs/dampers, but I distinctly remember it being much better when I first bought it.

On the contrary, it should handle short bumps and speed humps much better than conventionally sprung cars... the long rebound time is an asset for short bumps as its the short rebound time of stiffer steel sprung cars that make them react more violently over speed humps etc... If its handling speed bumps worse than a regular car there is definitely a fault.

I've just had the spheres renewed, changed the LHM and cleaned the filters for the second time in a year (by a mechanic specialised in old hydro Citroëns), the height regulators were cleaned and well greased, the system was bled thoroughly, but the problem remains.

Any ideas as to what could be wrong?

I seem to remember reading about it being a problem with the ant-sink valve, but I found no explanation on this.

On a 6 sphere car like yours there's really not much that could go wrong to give your symptoms. As Xac says - check the ride height first. The following thread has details on how and where to measure the ride height:

http://www.frenchcarforum.co.uk/forum/v ... =3&t=44115" onclick="window.open(this.href);return false;

It's important not just that its correct, but that consistently arrives at the right height +/- 10mm or so each time it makes a correction for load changes. So test it after loading and unloading the car to make sure it consistently comes back to the correct height.

If that's ok then spheres is about all it can be, perhaps you've got some duds that have died quickly for some reason.

You don't mention whether the "bouncy" ride is only at the front, the back or at both ends ?

Also how far down can you press both the front and rear suspension with body weight ?

[Jogador]

On a 6 sphere car like yours there's really not much that could go wrong to give your symptoms. As Xac says - check the ride height first. The following thread has details on how and where to measure the ride height:

http://www.frenchcarforum.co.uk/forum/v ... =3&t=44115" onclick="window.open(this.href);return false;

It's important not just that its correct, but that consistently arrives at the right height +/- 10mm or so each time it makes a correction for load changes. So test it after loading and unloading the car to make sure it consistently comes back to the correct height.

If that's ok then spheres is about all it can be, perhaps you've got some duds that have died quickly for some reason.

You don't mention whether the "bouncy" ride is only at the front, the back or at both ends ?

Also how far down can you press both the front and rear suspension with body weight ?

Thanks for the ideas.

First, the spheres were checked this tuesday by a pro and were found to be in top order (although a bit flat, hence the recharging).

The ride height was also checked and no faults there (but it was measured from the ground to the top of the wheel arch). There was, however, a difference in the rear ride height, the right side is approx 2cm lower than the left side.
It's supposed to level itself out, but it hasn't.
When I'll find the time I'll check the height with the aforementioned formula, to be sure. To my mind, the rear is a bit low...

The bouncy ride is both at the front and back, which is particulary weird, but there may be a slight change between front and back (i.e. the back being stiffer than the front).

As for my bodyweight, I can press the car down to the point where the rear wheel is inside the arch, until it levels out again. Front suspension can't be depressed that much. as the ride height is larger in the front, but is stil very giving if I sit on the bonnet.

Thanks for the ideas.

If all else fails, I'll take it to a specialised mechanic, but the car is quite rare in our country and therefore qualified mechanics are hard to find and also charge a ton...

[Hell Razor5543]

A rough rule of thumb (finger) is that you should get three fingers between the top of the wheel and the wheel arch, and one for the rear wheel and arch.

[CitroJim]

Bouncy suspension on a Hydraulic car, where the overall suspension still feels soft, is entirely due to failed or worn damping elements in the spheres. They don't last for ever and this limits, eventually, just how many times corner suspension spheres can be recharged.

How many times have your spheres now been recharged Jogador?

I had this very problem with a set of recharged spheres on the rear of my Activa. I checked the spheres for pressure and they were fine but after checking everything else I tried new spheres and all was then good again.

You can sometimes tell if the damping elements are worn by trying to rotate the disc on the end of the sphere. If it is loose and easily moved then the element is worn out.

I suggest you invest in a brand new set of spheres but do ensure you get the correct ones for your car.

[Mandrake]

I would agree with Jim's suggestion, just because the spheres have been regassed doesn't mean they're ok. The damper valves could be worn out, or they may not even be the right spec of sphere in the first place, as different variations of spheres have not only different gas pressure but also different damper valve calibrations, and you can't tell from visual inspection what the damper valve calibration is, only by part number. A set of new known good spheres is the only way to be sure.

Also when you say the rear height is 2cm different between left and right side - the only thing that can cause this (other than structural damage to the car or uneven tyre sizes) is the car being parked on uneven ground!

Check it again when the car is on perfectly flat ground and I'm sure you'll find they are the same. If you're trying to measure the ride height and can't find some perfectly flat ground to do so measure the left and right side and take the average. If the ride height has been adjusted whilst measured only on one side and the ground is uneven the ride height will be incorrect.

[Peter.N.]

I would agree with Jim, except for my C5 which felt solid at the back after changing the spheres - it was, the radius arm bearings had seized, that apart the ride must be down to either flat or the wrong sort of spheres. I assume a 6 sphere model isn't hydractive (never had a non sink car) in which case if hydractive spheres have been fitted it will be hard.

A good guide is to bounce the suspension, if the spheres are good you should have about 6" of up and down movement at the back and 3"-4" on the front, if you have nothing like this the spheres are flat - or the wrong ones.

Peter

[Andy F]

I am following this with interest, as my 2001 Xantia has had new spheres but no improvement in the ride, its also a 6 sphere non hydractive version. I changed them on my 1995 Xantia and immediately had the Citroen ride I had experienced in the past. So I was disappointed when I changed all the spheres on my latest one and the ride is still firm. It feels like a conventional car.

My point is, is it possible that GSF gave me the wrong spheres as they might have assumed a car as late as 2001 was hydractive?

I guess hydractive spheres are firmer as they use central spheres to make the ride soft?

This might have also happened to the OP?

[Mandrake]

Could be that you have Hydractive spheres Andy, that would make the ride very firm and heavily damped - it would still absorb large bumps but small bumps will pass right through. On a Hydractive system the centre sphere gives about 70% of the apparent ride quality and is the only thing that absorbs small bumps and slow undulations.

Can you post the part numbers on your spheres, assuming they're still legible ? Alternatively there is a quick check to see if you have Hydractive spheres on by mistake - take one of the front strut spheres off and measure the diameter of the centre hole in the damper valve.

The best (only ?) way to measure this accurately is if you have a set of fine "number drills" which you can try inserting into the hole to check for fit.

A Hydractive front will be 0.7mm, while a standard front will be around 1.5mm depending on model.

Likewise a rear Hydractive will be 0.6mm for hatchback and 0.8mm for Estate, but for a standard system it will be 1.2mm / 1.25mm respectively.

The following tables have lists of the correct sphere parameters for various models, although they only show OEM part numbers:

http://homepages.igrin.co.nz/simon/imag ... a_spheres/" onclick="window.open(this.href);return false;

Amtex, IFHS etc have their own part numbers...

Peters point about rear trailing arm bearings is a good one, if they're really bad they could make the rear suspension ride poorly despite the correct spheres, however there isn't really an equivalent fault possible with the front suspension, (even worn front struts won't ride as badly as worn out rear arm bearings) so if both ends ride poorly its more likely you've got the wrong spheres.

[Andy F]

Sorry to hi-jack the thread, but it maybe the cause of both of our problems!

The numbers on the sphere are
453PC0210

Many thanks in advance

[Old-Guy]

Hi!
I've just had the spheres renewed, .........

"Renewed" = Replaced? If so, perhaps the wrong spheres were supplied and fitted - this is not unknown as all spheres look much the same. I believe that both A/S and Accumulator spheres have no damping elements, and it's not inconceivable that a pair of accumulator spheres were fitted as front strut spheres and a pair of A/S spheres on the rear corners. This would explain all and seems to me to be the most likely explanation.

[cc101]

GSF supplied me with hydractive spheres for non hydractive sinker, double checked the part numbers on their website against the ones I fitted on the car, they were for a hydractive, phoned them and explained, they gave me the right ones and said I could keep the hydractives!

[Jogador]

Some good ideas here...

I may just end up buying new spheres, but just for the sake of argument (and maybe saving a few €):
The front ones are actually a newer type (from a C5- still green and round but made in such a way, that when they fail, they're ruined-the hydrogen leaks directly through the membrane when it bursts, as opposed to original xantia ones, where the hydrogen can leak around the membrane). The rear ones are approx a year and a half old, and they've never been recharged except now. The anti-sink has no damper membrane, the other ones do, and the accu is literally 4 months old.
I did check the ride height, and it is spot on (+/- 1 cm), the travel in the suspension is larger at the back than at the front.

So you can see my hesitations with buying new spheres, as these show all the examples of perfect health, yet the car rides guite bouncy...

[Peter.N.]

Have you done the bounce test? That will confirm it the suspension is sub standard.

Peter