Citroen XM Forum

I think i need to change the front centre sphere !

Now still being new to Xm ownership, i'm still not sure about what the centre spheres purpose is,

When i switch off i get a loud hissing from that sphere and the front of the car sinks, i know to top two corner spheres are fairly new , and the front seems to give a ride that is no better than a normal car, ...!

Does this sphere have any affect on the ride quality ?, if so i think this could need changing, the rear is fine and soft , as it had a lot of work done on that in Geneva, just before i purchased the car, the front does seem a little hard.

When purchasing this sphere , is it the same as a normal sphere that is on the four corners, or is it a particular one that has to be fitted ??

Nigel

Hi Nigel,

The centre spheres on each axle are the hydractive spheres. These spheres give most of the comfort on the car.

They are specific spheres, so you'll have to buy the correct ones for it. But they're the same price as all the others from the likes of AEP or GSF.

Robert

harryjoe wrote:....................
When purchasing this sphere , is it the same as a normal sphere that is on the four corners, or is it a particular one that has to be fitted ??

Nigel

Hi Nigel,
The corner spheres are completely different as they have a damper/valve fitted integrally into the sphere on the the large threaded end, unlike the Accumulator/Hydro-active centre (front/rear) spheres which have NO damper/valves fitted to them.
For the front Hydro-active centre sphere you need one which has a capacity of 500cc and 70 bar of pressure according to THIS chart (IIRC the 2.5 TD's are actually 72 bar) but it's only 2 bar which is only a small difference !



XMX

If by "front centre sphere" you mean the one that is visible under the bonnet then that is the accumulator. Its job is to store hydraulic pressure and it doesn't directly affect ride quality. If in good condition, the punp clicks every 30 seconds or more (actually the clicking is a valve closing).

If it's the one under the car behind the engine then that's the front hydractive sphere. That one does affect ride quality and you should follow the advice given by XMX.

Derek

Many thanks for the advice guys !

Just purchased the said centre sphere from GSF in Hastings, so will have a bash at trying to get it undone !!!!!!

Seems by reading other posts that it can be a bit of a bugger to get undone, so gunna find myself a four poster, and have a try .

I will adopt the same routine as removing the Accumulator sphere,


Nigel

You will probably find that its fairly tight all the way because you cant completely depressurise it, unscrew it enough for the fluid to leak out slowly and wait until it stops dripping, it will then unscrew easily.

Peter

Lower the car then loosen the pressure regulator bleed screw, which will fully de-pressurise the system and make the sphere really easy to remove without oil squirting out at all.

Lower the car then loosen the pressure regulator bleed screw, which will fully de-pressurise the system and make the sphere really easy to remove without oil squirting out at all

If you're lucky!!

Each one of these centre front hydractives I have changed has resulted in a shower of LHM after a fight to get the bandit off. On my Si, Ciaran's SEi and my VSX. Absoulte pigs to get off!

Enjoy!

Yes , thats what i did with the change of the accumulator sphere, but i have been readiong that they can be a lot tighter,,

'N' i thought that then when i tried to get that off

Will attemept tomorrow, !!!!

Correct de-pressurising procedure is in the PRIVATE CAR BOOKS post in the self help or now available on the Citroen Sevice website and should be followed.It is of course in other publications but readily available here.My particular experience is of very lttle residual pressure if the procedure is followed.Although some spheres were tight,never so that they needed big bars or hammers.
robertm