Xantia hard rear!

simoncanfer · Unread post by **simoncanfer** » 10 Mar 2008, 10:18

In the space of a day my newly acquired Xantia's ride has gone from "perfect" to uncomfortably hard at the rear.

Spheres are just over a year old and I believe they were regassed versions.

The height corrector seems to work OK, in that it reaches any set height after say 30 seconds. It is terribly rusty though!

The rear does sag quite fast once the engine stops.

Does this mean the rear spheres are gone? Or does the sinking mean an anti-sink function problem?

Simon

Xantia HDi LX 1999
I don't think it's hydractive...

KP · Unread post by KP » 10 Mar 2008, 10:45

If the rear sinks quickly it would point tio the anti sink sphere or the anti sink valve at the rear of the car for me.

The sphere is easy enough to change once the car is secured on some posts and NOT on just a trolley jack and then the system depressurised.

This is the quickest and easiest thing to fix first if there is no service record of it ever being done.

Regassed spheres you say though... Where were these regassed?

Also they should be regassed every 2 years i think plaidies reccomends for them?

Unread post by **RichardW** » 10 Mar 2008, 12:17

This has little or nothing to do with the anti-sink sphere.

Either:

1. The height corrector is bust and the car is running at low or high rather than normal; or
2. One of the rear wheel spheres has burst its diaphrgam.

To check 1, start the car and allow the height to stabilise. Does it look right? ie the car's about level, and you can just see the top of the rear tyres. If not, then HC is bust probably.

If it passes 1, then it's almost certainly 2, and a new pair of rear spheres is in order.

simoncanfer · Unread post by **simoncanfer** » 10 Mar 2008, 13:36

It's 2 then, spheres The rear feels solid when I push down on it compared to the front. Perhaps one side is softer then the other but i think I'll do both spheres anyway.

The back of the car rises up to correct height promptly and stops "positively" so to me that says the HC is operating properly.

Any point in replacing the antisink sphere as well?

Thanks RichardW!

Simon

KP · Unread post by KP » 10 Mar 2008, 14:48

My Appologies for a wrong diagnosis

If it were me and it soon will be as my rears are well overdue for replacement, it makes economical sense to spend the extra £25 on the anti sink sphere and do it while the car is up in the air if you are uncertain of its age in my eyes. If you know its been done in the last few years it could well be fine but im sure much more expert advice will be forthcoming

simoncanfer · Unread post by **simoncanfer** » 10 Mar 2008, 22:42

So how does one replace a sphere once it has burst and dumped fluid from the "nipple" ?!

Anyone want an LHM-soaked spare tyre?

Advice seems to be to crack the sphere off under pressure, to avoid damaging other components...that's a little difficult now!

admiral51 · Unread post by **admiral51** » 10 Mar 2008, 22:54

Hi simoncanfer
ive never had the pleasure of dealing with recharghable spheres but the idea of cracking the rear spheres under pressure is not to prevent damage to the spheres themself but the other components they screw onto
im not sure on the tech term but if not cracked under pressure then you run the risk of arms etc twisting and pipes bending etc which gets expensive and frustrating

if you are going to replace both rears i would do the anti sink at the same time if only for piece of mind

if you do the anti sink you must undo the 9mm

nut behind it before you attempt to remove the sphere or you will be looking to replace pipework

colin

Unread post by **RichardW** » 11 Mar 2008, 07:41

Hmm, that might well be a challenge simon, depending on how tight / rusted the sphere is. When it was regassed was it removed, or done on the car? All you can do is try and see if you can turn it without turning the cylinder and ripping the pipe off. I've never actually done any rears so don't know for sure - but you might be able to jam the cylinder against the pipe boss or something?

juraj · Unread post by **juraj** » 11 Mar 2008, 10:20

By what you are saying 'once it has burst and dumped fluid from the "nipple" ' - did you undo the the bolt or regassing fitting on the top of the sphere? because a sphere does not just burst, it is quite thick steel, anyway even if you did it doesnt really matter but it makes a mess. And you have to clean the sphere well if using a strap wrench otherwise it will slip.

I just did a set of rear spheres and they were really tight. Firstly do not try to crack under pressure, this is almost impossible or at least very difficult, under pressure there especially under full pressure there could easily be 1000psi++ in the there meaning there is a lot of force on the sphere pushing it outwards, thus there is a lot of axial force on the thread at the sphere base and you will need a huge lever and a serious strap or chain wrench to over come this friction. I bought my heavy duty strap from eaby - approx £10.

Anyway my spheres were so seized up by corrosion, they were very very difficult to get off, I use a heavy duty canvas strap wrench and i removed the supply pipe to the cilinder to prevent any damage. I have never seen such seized on spheres as im from australia and the weather conditions there mean sphere removal is always quite easy. Back to england, these were so tight that as i tried to unscrew them the bracket which the pipe boss on the cylinder protrudes through got totaly bent, in fact the strap wrench was also starting to slip. You can not do any other damage, the trailing arm can not bend as the cylinder and piston can rotate against each other, thus the piston stays staionary, if take the extra measure of removeing the big spring clip fastening the piston to the trailing arm, then the cylinder and piston become totaly isolated only that 'way too thin' bracket stops the whole from rotating - or not he he - all that happens is that the cylinder turns. Anyway this bracket became so bent out ouf shape I had to go to plan B which is a large cold chisel and a 1.5 or 2 lb hammer, after a few good swings the spheres let go, always do with this method.

Anyway i tried to bend back the brackets back but they still remain somewhat bent, their holes elongated, this is no big beal, they are only there to aid in sphere removal is my guess, have no other purpose. GSs have a virtually identical set up but no bracket so you have to hold onto the cylinder as well as screw the sphere.

When fitting new spheres it is only necessary to hand tighten them, the internal pressure means they stay on, even hand tightened spheres need a tool after a few days on. If i was to live here permanently and have citroens, then after doing such tight rear spheres I would just loosen them and reapply them every 6-9 months or during a 6000mile oil change, this would take 10 min and save the trouble every 2-3 years.

bye

simoncanfer · Unread post by **simoncanfer** » 11 Mar 2008, 12:15

Thats interesting, thanks.

You're right, my leak is from the regassing point on the end of the sphere. Is that tightenable? I'll feel very silly if I could have simply tightened something loose to avoid an oil slick...

The spheres were from Westroen and have been on for about 18 months so I hope they're not that tight. We'll see.

Quite why my local dealer have stopped stocking 3.5mm seals is a mystery: is replacement of these seals compulsory?

slim123 · Unread post by **slim123** » 11 Mar 2008, 12:23

Hi Simon.

If the leak is from the filler plug, the sphere will be completly flat and the diaphragm inside will have burst, there should be no oil on the filler plug side of the sphere.

On the side of tigtening, there is no need to ever touch the filler plug, all you will do here is let the gas out, this is why Citroen use a round filler plug rather than a hex, it's to stop fiddlers with spanners.

Also get some cheap washing powder and wash that tyre, the LHM will do it no good at all.

I get plenty of 3.5mm seals from Pleiades, and spheres! They are handy to me as I live just up the road.

Regards
Slim.

Unread post by **RichardW** » 11 Mar 2008, 12:43

Have you got a receipt for the spheres - Westroen do a 2 year guarantee IIRC - he may even a record of doing the work and cough up another sphere.

'Cracking' the spheres whilst under pressure is standard practice in the UK - the usual level of corrosion makes it much more risky to try and remove the pipe if you don't have to.

Standard practice is to replace the seal if you disturb the pipe, but it will probably seal on the old one. Don't overtighten it, just nip it up then pressurise it - if it weeps, nip it up a bit more.

juraj · Unread post by **juraj** » 11 Mar 2008, 12:54

well i guess you would want to crack it under low pressure not full system pressure

also if that filler bolt/plug is the source of your leak and you did not disturb it then this is a 'serious' fault, serious as in that should not happen on its own and if they are re gassed then most likely it was not tightened properly, and a replacement under warranty should be given. it makes sense though as once the seal goes all your nitrogen escapes the car is suddenly very hard form one day to the next, usually a sphere will go progressively harder over months, not over night, and eventually the diaphragm gets ruptured and then its totally hard. sounds like you have a real claim here, even if out of warranty its pretty embarrassing that the seal let go, if i was the supplier id replace it just to save face

Unread post by **RichardW** » 11 Mar 2008, 14:10

"well i guess you would want to crack it under low pressure not full system pressure "

No, full system pressure - the more the better

It's not unknown to have to add a few bags of sand (or heavy mates

) to the boot to get enough weight on the cylinder to prevent it turning. Providing you go no more than 1/8th turn it will not leak. Too much

Monkeyfeet · Unread post by **Monkeyfeet** » 11 Mar 2008, 17:15

Yep, got to vouch for the full system pressure with the missus, the kids and a neighbour or two sitting in the boot method. Also agree very much with the only needs an eight of a turn bit, too.

Yes, I have good axle stands!