Xantia suspension hard despite new spheres

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Jogador
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Re: Xantia suspension hard despite new spheres

Post by Jogador »

Mandrake wrote:
Multilayer Xantia spheres (the ones with the three dimples around the filler cap at the top) are designed much like C5 spheres and can last 10 years without needing regassing. One lesson Citroen learnt with the multilayer design used on some Xantia spheres is that in cold temperatures the middle layer is brittle and has a tendency to crack if the diaphragm is over flexed - in these conditions the center layer splits causing the sphere to lose pressure much faster and mechanically tear the outer layers, so the sphere will fail soon after. Because of this the multilayer spheres were only "trialed" on the front suspension of the Xantia, where the engine bay keeps them warmer than rear spheres. To rectify this C5 spheres were redesigned to be short and squat - thus greatly reducing the required diaphragm flex, making them more robust...
Was reading through this again, my front spheres are as described here, xantia spheres with the three dimples around the top.
So my xantia has some experimental (and flawed=)) stuff on it :mrgreen:
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Re: Xantia suspension hard despite new spheres

Post by Mandrake »

Jogador wrote:So much for a quck and cheap fix...

The bouncy ride is back :evil:
Drat! I hate to say it but I'm not surprised, I spent years chasing air bubbles being drawn into the hydraulic system on my previous Xantia and never completely got to the bottom of the problem, I was able to prove conclusively that air bubbles were being sucked into the pump but not where they were coming from. :( The result was intermittent harsh/bouncy ride. This type of problem can be very intermittent and seem to be fixed for a while but then return later.
Also, the rear is again starting to shoot up under braking. Once or twice, the rear end even dropped drastically when releasing the brake pedal-this was also the case when I first bought the car and the hydraulics really weren't taken care for (lhm replacement and brake bleeding sorted it right out). There is no frothing in the lhm tank, even when testing with the trick for flushing out air.
My best guess is that the anti-sink membrane is leaking continiously (even more now, since it's been regassed) and the nitrogen is getting into the rear brake circutry (where it can't escape because of the length of rear brake pipes). My only idea, as there's no air bubbles in the lhm tank and this sphere is a reserve for the rear brakes.

Sounds plausible or even possible? 8-[
Yes very plausible, I concur with Xac's comments on a ruptured anti-sink sphere.

I've personally seen a ruptured anti-sink sphere on my Dad's Xantia that was bubbling nitrogen into the rear suspension and brake lines constantly.

The rear suspension was shooting right up even under modest braking (always a sign the rear brakes aren't working) so of course I bled the brakes and they worked fine for a while. Just a few weeks later the rear was shooting up again under braking, I bled the brakes, large quantities of "air" came out again and the brakes were fine...a few weeks later it was shooting up at the back again under braking...you get the idea :wink: This went on 3 or 4 times until he had the money to replace the anti-sink sphere, we did one final bleed after that and the problem never came back. The sphere squirted out a steady stream of oil when removed too which is typical for a sphere with a punctured diaphragm. A pretty open and shut case! :)

As far as I can see this would only affect the rear suspension though, is your "bouncy ride" only at one end of the car or both ?
Simon

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Re: Xantia suspension hard despite new spheres

Post by Mandrake »

Xac wrote: Also while you're under the car, check that the manual height adjuster is situated correctly in the end of the arm that comes out of the actual height corrector.
One of my cars would be really hard at the back, then sometimes it would go soft until I went over a speed bump where it would go hard again.
Turned out the pip on the side of the manual linkage wasn't sitting in the middle of the square hole, it was pressing slightly against one edge of it holding the rear ever so slightly too high.
So the manual and self levelling were fighting each other, the pip would sometimes be pulled out of the square hole and the rear would drop to the right height and be lovely.
Going over a speed bump would send the rear up, the pip would pop back into the hole and prevent the rear dropping down to normal.
The height looked normal though.
Very interesting comment Xac, I may have the same problem on mine at the rear, the rear ride height is not well regulated and the rear sometimes feels very "bouncy" as if the ride height is wrong. I know the linkage is a bit sticky causing an overshoot of about 35mm on static testing, but haven't checked the manual override adjustment peg is centred properly...

When driving it sometimes feels like the car is leaning back too far, I know the front ride height is correct and well regulated so that would mean the rear is sometimes too low. I also notice that setting the manual height lever to maximum with the wheels unsupported won't allow me to bleed the rear brakes (I have to keep load on the wheels as well) which usually means the manual override linkage is adjusted wrong, towards the down direction. Co-incidence ? ;)
Simon

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Re: Xantia suspension hard despite new spheres

Post by Mandrake »

Jogador wrote: Was reading through this again, my front spheres are as described here, xantia spheres with the three dimples around the top.
So my xantia has some experimental (and flawed=)) stuff on it :mrgreen:
Haha, not at all, :) the multilayer diaphragm spheres are very good, they seem to last over 10 years without any loss of pressure and I prefer them, but there was obviously a reason why they were only ever fitted to the front struts and front hydractive regulator, and not all all markets, and a reason why they changed the shape of the sphere for the C5.

They never used them for the pressure regulator, nor any of the rear suspension spheres. Pressure regulator I don't know why, but rear suspension spheres I've been told because of the much colder temperatures experienced there compared to front strut spheres.
Simon

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Re: Xantia suspension hard despite new spheres

Post by Jogador »

The rear HC is in (suprisingly) good order (the car was kept in a garage most of it's life), and also all the linkage parts are in good working order (confirmed when I had the spheres regassed), there is no sticking, all the parts fit perfectly, and the response time is excellent.

Hopefully this weekend I'll get the chance to bleed the rear brakes, if there's air in them, I'll order the anti-sink sphere, and then bleed the whole system properly.

The bumpy ride is, I think, worse at the back, but also at the front it's not ideal.
My guess, some small part of nitrogen got out of the rear part of suspension when I was doing citaerobics after bleeding the brakes...


Slightly off topic: when really pressing (stamping would be more appropriate) on the brake pedal and then releasing it, there is a sound like some air being either compressed or released, but only during the first part of the pedal returning to it's original position.
Could this be a sign of air/nitrogen in the main pressure regulator, or an o-ring inside may be leaking a bit? There's no loss of lhm though...

Or is this the result of the special brake pedal setup xantia has (some sort of spring-loaded tube I vaguely remember reading about)?
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Re: Xantia suspension hard despite new spheres

Post by Mandrake »

Jogador wrote: Hopefully this weekend I'll get the chance to bleed the rear brakes, if there's air in them, I'll order the anti-sink sphere, and then bleed the whole system properly.
Good idea. The anti-sink sphere because it doesn't show much in the way of symptoms when it goes tends to get forgotten about and never replaced. So if you've never replaced it chances are it will need it.
Slightly off topic: when really pressing (stamping would be more appropriate) on the brake pedal and then releasing it, there is a sound like some air being either compressed or released, but only during the first part of the pedal returning to it's original position.
Could this be a sign of air/nitrogen in the main pressure regulator, or an o-ring inside may be leaking a bit? There's no loss of lhm though...

Or is this the result of the special brake pedal setup xantia has (some sort of spring-loaded tube I vaguely remember reading about)?
If you're talking about a loud "slurp" just as you release the pedal after pressing it down hard, its perfectly normal, they all do it. :)

It's just the sound of oil travelling at very high velocity through tiny openings, it makes a noise for the same reason water travelling fast through a partially closed tap does...
Simon

1997 Xantia S1 3.0 V6 Auto Exclusive in Silex Grey
2016 Nissan Leaf Tekna 30kWh in White

2011 Peugeot Ion Full Electric in Silver
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Re: Xantia suspension hard despite new spheres

Post by Jogador »

Mandrake wrote: If you're talking about a loud "slurp" just as you release the pedal after pressing it down hard, its perfectly normal, they all do it. :)

It's just the sound of oil travelling at very high velocity through tiny openings, it makes a noise for the same reason water travelling fast through a partially closed tap does...
One less thing to worry about/take apart/destroy in the process. :mrgreen:

OT: I also got the tyres/rims installed, they look awesome, like new, but the tyre-fitting "expert" destroyed almost the whole outer edge of one rim...
I wasn't there (maybe for the best, I can be quite irritable when somebody ruins my hard work and expense with lackadaisical work-I might get really angry) and the official excuse was that the rims were like that when I brought them... :evil:
After almost half an hour of "negotiations", I got nowhere, so I just fixed the edge as best as I could (to be frank, only I know that it's been reworked after the refurbishment). Of course, the rim with the "repaired" edge was the smoothest-rolling one, so it now sits at the front left wheel, for me to look at avery time I drive somewhere :-D
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Re: Xantia suspension hard despite new spheres

Post by Jogador »

The damn thing is obviously sc*ewing with my head! :evil:

So I bled the brakes, no air in them, suprisingly. The anti-sink, I think, still needs replacing, the car is sitting down way to fast when turned off as opposed to when it was regassed. The ride is still choppy, although some of it is down to new summer tyres (the higher velocity index means a stiffer tyre, and mounted on wider rims, there's less travel in it, no to mention the winter tyres were really soft-there will be a difference in the ride quality), but I still think there's more to it than that...

Honestly, I'm running out of ideas. There's a tiniest of leaks on the hi-pressure pipe from the hydraulic pump to the front height corrector, but it's been there since I have the car. The ride height is ok, the HCs work well, the struts are lubricated, no frothing of lhm is visible regardless of what the car is doing.
I'll probably end up buying some new spheres... :?
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Re: Xantia suspension hard despite new spheres

Post by elvito »

Hi, did you manage to solve this problem? I am experiencing the same problem as well.

Thanks.
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Re: Xantia suspension hard despite new spheres

Post by xf1ref »

When I bought the car I went to someone for a total hidraulic restoration and after 2 years I found that the car have hydractive spheres...he changed original spheres with others for xantia hydractive.
The suspension is very different , on highway or outside town and in cornering is very stable but on roads like cubic stone is harder than other cars with springs.
Now I am accustomed with that, even if I don't feel the flying carpet.
I found this measuring the spheres holes.
Hope you don't have other spheres like me.
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