Question for ROW: Citroen C5 suspension Spheres

shamwari

Row, I've one here I think you might hopefully know the answer to.

A mate has a Citroen C5 (2003, 1.8 with spark plugs) which he complains is suffering from very stiff suspension. It sounds like a sphere or two is kaput.

I won't be repairing this one for him, but are there any simple tests that can be done to confirm or eliminate the sphere's from the equation? Also, is specific diagnostic equipment needed to mitigate or relieve the hydraulic pressure before working on the system. The old Xantia was ride height up / crack open pipes / ride height down / sphere's off before working on it, but I reckon this beast is different....:eek:

Thanks!

Sham

slimjimmc

I believe C5's hydractive 3 suspension uses 4 combined pump/sphere units, one on each strut.

Officially it's a dealer job to tell the suspension ECU to dump pressure but it seems (as usual) a workaround exists:
http://www.citroen-owners-club.co.uk/citroen/index.php?showtopic=7985

(and I thought you just need to open a release nut on the Xantia's pressure reservoir).

Row

shamwari,
Sorry i'm not so familiar with these as i spend most of my time with Peugeots...:o
I have lexia but never needed to depressurise the hydraulic system on a c5.
I'd say the option is in there but never came across it.
My Citroen servicebox is also down at the moment and i cannot access info
atm...:(
I have a 05 C5 coming to me Monday/Tueday so 'll check and see if the option is in there.
Interesting link there slimjimmc...;)

shamwari

Thanks for that chaps! Just wondering, are the syptoms the cars owner is complaining with (hard suspension) consistent with defective / worn spheres?

Row

shamwari wrote: »

Thanks for that chaps! Just wondering, are the syptoms the cars owner is complaining with (hard suspension) consistent with defective / worn spheres?

I would imagine that an over pressurised system would cause hard suspension and worn defective/spheres would createthe opposite.
Have these hard suspension symptoms been always there or just in the last while..?

shamwari

I believe that the suspension issue has been there a while but getting steadily worse. I thought from what I know about the Xantia's, this seems to be to do with Sphere's, but obviously the C5 is a different car / system entirely. The cold weather had no effect on it.

mrbig

I have had a few Citreons over the years and the problems with the spheres always produced a bouncy ride. is it possible that your pressure regulator is the problem, mayby this can be affeceted by cold the fluid will definitly be more viscous.

slimjimmc

Row wrote: »

I would imagine that an over pressurised system would cause hard suspension and worn defective/spheres would createthe opposite.
Have these hard suspension symptoms been always there or just in the last while..?

In fact defective spheres do result in harder suspension and not a softer one. The spheres contain pressurised gas (nitrogen?) which sealed behind a flexible diaphragm connected to the suspension strut. The gas performs the same function as a steel coil spring (i.e. supports the weight of the car), while the hydraulic strut provides the damping.
Over time the gas can leak through the diaphragm. There is less gas within the sphere to compress and provide a soft spring and so the ride gets harder and bouncy. It's a bit like taking a few coils out of a steel spring.

Andrew Campbell

I agree with slimjimmc's answer, if you start the engine and bounce the car in each corner you'll soon find the firmer sphere. the problem is they get progressievly worse so sometimes its difficult to diagnose a half worn out one!!! Its also better to do them in axle pairs. They can be recharged and in the past Dolphin Motors in clontarf have done it for me. they can even do them when still on the car. Occasionally the diaphram is split and cannot be recharged. There is a lot of pressure on these and dismantling is best left to an experienced person. Releasing the pressure (using the 12mm nut on the regulator) does not release the fluid pressure at the spheres or the remaining nitrogen in the spheres. You should also consider having the accumulator recharged at the same time as the front ones. The tell tale for this needing to be done is the pump cutting in and out too often. If you do need to get new ones in the past i've used a place called Andy Spares a citroen specialist in UK and got some great value.

Row

Some informative reading here..
http://www.citroenet.org.uk/miscellaneous/hydraulics/hydraulics-16.html
http://www.citroenet.org.uk/passenger-cars/psa/c5/c5tech1.html