Which spheres do i need to change?

vince · Unread post by **vince** » 10 May 2010, 21:09

Hi guys, just having a read of the official Citroen training manual on hydractive suspension....One paragraph interests me greatly....this one:

If the hydraulic pressure is not sufficient, the
additional sphere remains isolated, which, when the
engine is switched on, can cause a slight jolt.

Which mine has now started doing sometimes.

As you may know my car (95 Xant) has had an on / off soft to hard mode suspension issue for some time now. Mostly this has been suspected as a duff rear electrovalve even though it buzzes as normal for the 30 second interval whent he doors are opened etc.

The rear of the car does not rise when you sit on the boot lid unless the engine is running highlighting a flat rear accumulator.

From the paragraph above im now of the opinion that as the rear suspension pressure is low due to this sphere and also no doubt the other rear ones, (they are all old) that this is leaving the third centre sphere isolated resulting in hard mode on the rear for a period of time. This does reset itself to soft after a few minutes at idle which is no doubt the rear suspension getting back up to full pressure therefore unisolating the rear centre sphere....

Does that sound plausible? If so should i just replace the lot?

P.s. The manual on the XM forum is the business.....it should get posted on here

falling-out-with-my-car · 10 May 2010, 21:48

vince I would have thought you were in the position to get the lot vat free matey, so why not change the whole lot and with a permenant marker pen put the date and year on the front two spheres so every time you lift the bonnet you know how old they are.

pleidies fits them to for the same price as GSF by the way. unless you can get em cheaper that is.

Unread post by **xantia_v6** » 10 May 2010, 22:15

The paragraph you quote above is refering to line pressure (from the regulator) not sphere gas pressure. bad spheres will not stop the electrovalve opening. Your problem is probably either a weak spring in the electrovalve (as documented by Mandrake), or low pressure due to an out of calibration regulator.

vince · Unread post by **vince** » 10 May 2010, 22:45

Oh bugger....

I dont suppose changing them will do any harm....they need doing anyway

As for writing on the spheres....a good idea sure, but id rather keep the invoices and write on them. If i had writing on my spheres it would drive me mad everytime i saw it....ive unfortunately developed a bit of an OCD for things looking how there were intended to look

I know i need help....

Plus a new / fixed electrovalve

Unread post by **citroenxm** » 10 May 2010, 22:48

The rear end not rising when you sit on it - theres is no rear accumilator sphere at the rear that controls this, this feature is still fed from the front accumilator sphere..

So my guess is flat engine mounted accumilator spere, and possibly Flat rear strut spheres and "Hydractive" sphere, which on the Xantia, is mounted above the rear subframe on the drivers side..

The anti sink sphere - in the centre rear, doesn't have an effect on the "Sit on and Rise" exercise, its mearly a reserve to hold the car up when its started again after sitting for some time, to prevent the car from sinking..

In other words, as in my TD Anti sinker, the car stays up while the engine is stopped, so the anti sink valves work, however, in the mornings when I start up, the anti sink valves open and the car drops untill the pumps caught up.. this is due to the anti sink sphere being flat.. and I beleve its all it does.

Paul

Unread post by **Peter.N.** » 10 May 2010, 22:48

Its a duff accumulator sphere that will prevent it from rising when you sit on it, but as suggested I would change all of them, especially the centre ones, they are responsible for the soft ride.

Peter

Unread post by **CitroJim** » 11 May 2010, 06:49

Vince, did we not replace your accumulator about a year ago now?

If I recall, your car was showing a slow tick in hard mode and a fast one in soft, signifying a leaky electrovalve.

Ignition off, pull out F8 (the Hydractive fuse in engine bay) start up, let pressure come up and then switch off and try the "sit in the boot" test.

It is critical this test works before proceeding...

Check again the tick rate in forced hard 9with the fuse out) and then in soft mode with the fuse in. Only in and out the fuse with ignition off...

Unread post by **citroenxm** » 11 May 2010, 08:25

Peter.N. wrote:Its a duff accumulator sphere that will prevent it from rising when you sit on it, but as suggested I would change all of them, especially the centre ones, they are responsible for the soft ride.

Peter

This is only true when the engine is OFF as theres no reserve for the height corrector to use up... its a good test for the Accumilator otherwise..

Of course, with the engine running the car will come up.. but no movment sugests dead strut sphere..

Paul

Unread post by **Peter.N.** » 11 May 2010, 09:15

I assumed that was what he meant

vince · Unread post by **vince** » 12 May 2010, 23:32

CitroJim wrote:Vince, did we not replace your accumulator about a year ago now?

If I recall, your car was showing a slow tick in hard mode and a fast one in soft, signifying a leaky electrovalve.

Ignition off, pull out F8 (the Hydractive fuse in engine bay) start up, let pressure come up and then switch off and try the "sit in the boot" test.

It is critical this test works before proceeding...

Check again the tick rate in forced hard 9with the fuse out) and then in soft mode with the fuse in. Only in and out the fuse with ignition off...

Yes we did Jim so im reasonably convinced thats ok. the front corner ones were also replaced at the national rally. The rear spheres are all undoubtably "past it" as they all look rotten......The tick rate is still 8 seconds when the engine is running. I will test the fuse out thingy though Jim and see what difference it makes to the tick rate