Xantia s2 hard rear suspension

[charentejohn]

Just checking what could cause this as I have had a few problems / changes over the last months.
Bought the car which (bills provided) had all 4 spheres changed and always rode well.
Rear centre sphere has not been changed, but will be. Hydroneumatic 6 sphere setup.

Had a problem with an LHM leak which lost a lot of fluid a while back, fixed now, but since then rear was a little stiff. Front is ok, bounces like a normal car 1 and a 1/2 bounces to rest.
The rear drops about 3cm (1") if pressed hard and is very solid.

Recently lost fluid due to a split supply hose from reservoir to hydraulic pump, this may have made it worse, or could be my imagination.
I repaired the hose with a joiner which has 7mm internal dia., so would reduce flow by 20%. I have a replacement on order but steering seems a little heavier and suspension in general seems a little solider (lots of rattles on rought roads) which may be caused by this as much as air in the system ?

So.
I am about to finally fit Hydraflush and was wondering if I need to change spheres as well ?
I would rather change any spheres (rear centre) when I put the proper LHM back in the future.

Could it just be air or similar in the rear pipes ?
Brakes work fine but if I bleed them, as I will need to do, on Hydraflush fitting is this likely to cure the problem ?

Just trying to avoid doing the same job twice, that is fit hydraflush and find no change so still have to change spheres.
Hoping that fluid change and system bleeding will solve this, but will it ?

[Xaccers]

Probably air as your fix has lots of joints if memory serves so plenty of places for air to be sucked in.
Replace the old pipe with a single length of 8mm silicone pipe suitable for turbo boost gauges etc, cheap from eBay.

[charentejohn]

Thanks, I changed the dodgy copper pipe connector for proper 'barbed' plastic types so seems ok, apart from the one I think is too small.
I had the problem before fitting the connector that is too small but has definitely got worse since doing this last change.

I was wondering if air in the rear brake lines (just a bit) could cause this ? If so then when I change to Hydraflush and bleed the brakes it might go away, or should I fit new spheres as well bearing in mind they are supposedly about 2 yrs old.

[Mandrake]

First things first - if the rear suspension feels stiff and heavily damped and you know the rear strut spheres have been replaced recently but the rear Hydractive regulator sphere has NOT been replaced, this is your first port of call as most of the suspension travel and softness comes from this sphere, not the strut spheres.

The regulator sphere is often overlooked by those who don't understand the Hydractive system so its common to find a car where the strut spheres have been changed but not the Hydractive regulator spheres. Same thing happened on my previous Xantia, it had okish strut spheres when I bought it but the regulator sphere was punctured so the rear was stiff as a board...with that one sphere changed the ride was transformed.

Don't worry about waiting until you've flushed the oil before fitting a new sphere - dirty oil won't hurt a sphere, besides when you lower the suspension to depressurise, ALL the oil is ejected from the sphere anyway... so do the rear Hydractive regulator sphere now.

Another thing that could be causing the rear to be hard is a problem with the operation of the rear Hydractive electrovalve, it might be stuck in the "hard" mode due to a faulty diode or a mechanical problem with the electrovalve, however until you know for sure the sphere is good you can't tell - a punctured regulator sphere and a faulty electrovalve will give identical poor ride symptoms!

So if you fit a new rear Hydractive regulator sphere and there is no improvement then you would go down the route of troubleshooting the operation of the electrovalve, (possibly requiring the diode mod) but I think its much more likely you just have a punctured regulator sphere.

If you happen to have a spare accumulator sphere kicking about you can temporarily try that - the pressure is 62 bars instead of 50 but its close enough and actually gives a softer than normal ride. I had one on the rear of mine for a few weeks until I got the correct sphere and the ride was fantastic, only trouble is there was a lot of squat under acceleration.

To your other points - no, your smaller diameter repair pipe shouldn't have any effect on the ride quality, it might just take slightly longer to pump up the car in the morning. The steering may be affected though.

However if there is air being sucked into the hydraulic pump due to a less than ideal air tightness on the feed line from the tank to the pump (the line you repaired, and remember its under slight vacuum when the pump is running, so a leak won't necessarily leak oil) then this CAN cause a harsh ride on broken surfaces, in extreme cases the car can feel kind of bouncy like its lacking in damping.

I think most Xantias suffer from air ingress into the high pressure circuits to varying degrees, which can cause the ride to improve greatly after Citreorobics but then deteriorate over a few days of normal use.

The ride on mine sometimes deteriorates to become quite firm and somewhat harsh over broken surfaces, as well as becoming a bit under damped feeling at speed - if I simply lift the suspension to full height and let it idle for 5 minutes before lowing to normal height (NOT minimum height) then go for a drive the ride is vastly improved - harshness on broken surfaces is almost gone, the ride feels almost magic carpet like, and at speed the car feels supremely stable and well damped, but after a few days normal use it will deteriorate again...

[charentejohn]

Thanks, a good all round explanation.
As I will have to bleed brakes etc I may as well change the rear sphere. I do believe it can be tricky so as usual that is why nobody does it if they don't have to

I have to order parts so prefer to buy the lot all at once as always a delay in posting time can stop the job.
I am never sure of the purpose of the centre sphere, now I know.

The car is a little slow to put the Stop light out if left for a few days (about 30 secs) but if used daily it takes 10-12 secs when first started so seems ok.

[Xaccers]

If you have a SX then the ride quality comes from the corner spheres and you have no electro valves.
The middle sphere is a rear accumulator to give you rear brake pressure in the event of a pump failure and the anti sink spheres closing.

[Mandrake]

Argh!! Well spotted, I didn't notice it was an SX.

In which case ignore everything I said about Hydractive regulator sphere and electrovalve as the car won't have them!

The comments about air being sucked into the pump inlet are still valid though.

On an SX as long as the ride height is correct the only two things that could cause stiff suspension would be the spheres or the rear arm bearings... its most likely one of the rear spheres has failed.

[charentejohn]

No problem, I haven't ordered anything yet.
As luck would have it I have just been on the Sevice Citroen site trying to find the OEM for the centre sphere. Couldn't find it listed, just the 4 outer ones ?? I am sure they were there before, I used the car's Vin no so should be exact.

The garage (I use the term loosely) that worked on the car before I bought it is a bit suspect. You may have read comments I have made before about this.
They supposedly changed all 4 spheres and, this is the giveaway, put 3L of oil in the gearbox which we all know means they must have spilled quite a bit. So basically they did something and charged something-ish. Some other things I think they only half did too so not changing the rear spheres (where most people wouldn't notice) is quite likely.

I will replace the spheres, as car will be on low, do the Hydraflush change then bleed the system fully. Hopefully that will sort it out.

A question on reliability of Citroen Service.............
Just looked up front and rear spheres, in the Front section it says Rear Sphere and lists it as 55 bar, in the Rear section it says Front Sphere and 30 Bars.
Which is right ? seems the descriptions are mixed up, what is going on ??
I reckon it is just the wording so I need 2 x 5272-34 spheres I have multi choices
Most expensive http://www.oscaro.com/accumulateur-de-s ... 959-1718-p" onclick="window.open(this.href);return false;
Known brand http://www.oscaro.com/accumulateur-de-s ... 131-1718-p" onclick="window.open(this.href);return false;
New one on me but could be ok http://www.oscaro.com/accumulateur-de-s ... 087-1718-p" onclick="window.open(this.href);return false;

[Mandrake]

55 bars will be the front strut spheres, 30 bars will be the rear strut spheres, the rear centre sphere as you refer to it is known as the anti-sink sphere, its 50 bars and has a pipe union (and no damper valve) in the neck. The anti-sink sphere won't have any real effect on ride quality but its good to replace it for other reasons if it needs doing.

If your garage is a bit dodgy they may well have had trouble getting the rear spheres off and simply not done it! Are you sure they put 3 litres of oil in the gearbox ? Or do you mean 3 litres of LHM in the hydraulic system... Done properly you shouldn't loose more than about 1/4 litre changing four spheres, so either it had a big leak that they repaired or they made a real hash of doing the job!

As for OEM spheres, I don't know about in France but here in the UK I doubt that anyone on the forum buys spheres from Citroen... most would get them from AEP direct or GSF at a fraction of the price...

AEP supply IFHS brand and I think GSF do Amtex. I've had a set of IFHS spheres on my V6 for the last year and no complaints... they look just like OEM to me too. (I used to buy OEM spheres from Citroen in New Zealand where there aren't really any alternatives)

[charentejohn]

Thanks for the info on the different spheres, I will do the middle one as well as from what I read changing it means having to bleed the brakes. So as I will need to bleed them to do the hydraflush I may as well do it now.

I usually use Service Citroen to make sure I get the right part, specially spheres as there are so many depending on exact model. I guessed somebody just mistyped the front/rear in the descriptions.
That can be the problem buying online, that you can't see the part, so having the number is a big help.
I will try the anti sink bit in french and see if I can find it, problem is it doesn't always translate directly, any problems and I will order from the UK.

I don't use the garage but the previous owner did. It was shown as 3L of oil in the gearbox, I think they just did stuff and wrote anything. Just a confidence thing, if they said they used 3L when it is 2L do I believe they changed the spheres correctly. Other things don't look to have been replaced by new parts, more reclaimed. Still, running ok and I will sort things as they go.

Worth doing the work here as cars go for more, paid 2.5k Euro for mine and it is still worth about that. I would guess worth £500 in the UK ?
So as a car with faults is worth very little here it is worth spending the money. People spend the value of the car fixing it because it is a lot of bother to sell and get a new one, why so many old cars run around here. Just a different mindset, I need a car, to buy one would cost 2000, my broken one is worth 500, repairs are 1500, so I may as well fix it and have a known good car.

[addo]

Try (for aftermarket) "sphère anti-affaisement", pression 50Bar. Sometimes they even use the English name of "anti-sink".

[charentejohn]

Thanks, that's the one. Using google translate where you hover over the word it comes up with subsidence, sag, sinking and droop. So I will order an anti droop sphere then.
I can't find a section in Citroen service that gived the OEM but as long as it is a 50 Bar one that should be ok. Looks like this one http://www.mister-auto.com/spheres-accu ... .0046.html" onclick="window.open(this.href);return false; says hydropneumatic and 50 bar. I am assuming Lizarte are Spanish as that is where a lot of french one seem to come from.

[addo]

You've linked to one suitable; it gives the OEM numbers at the bottom (one early 96-code, and a couple of the 52-prefixed numbers).

[charentejohn]

Thanks for confirming.
Just checked up on Lizarte and they are spanish, goo site for info on spheres as it lists them with a fair bit of detail, you can put in make and model then select parts you want.
Shows details like hydropneumatc suspension so I know it is suitable for mine.
http://www.lizarte.com/en/Suspension-Sp ... 13186.aspx" onclick="window.open(this.href);return false;

So I reckon I will get ordering and make a start later in the week.

[addo]

Shame you can't grapple a bit more with the French yet; have confidence and even when it comes out terribly wrong, remember you've probably brightened someone's day. "Je suis possesseur un Citroën. Exposez votre pièces, s'il vous plaît."