Xantia F. suspension drops from max height - FIXED

[AndersDK]

How could the valve block dump such amounts of LHM into the Hydractive sphere - even the sphere hold this amount ?
The sphere would in soft mode (at low speed) quickly get the same pressure as the corner spheres.
This could then be the dump path to the reservoir from the valve block that sticks open in the shift soft to hard. And then the pressure in the sphere is dumped - until next soft mode occurs - and the sudden resulting height change.
Is this problem the wellknown O-ring failure in the Hydractive valve block ?

[alexx]

Well, assuming that front suspension cylinder diameter is 22 mm, only 7.6 ccm of LHM is needed for 1 cm height change (when the spheres are already at the working pressure, of course). Volume of hydractive sphere is 400 ccm, and several bar difference at the moment, when HA sphere gets connected to corner spheres, will do this. And it will be quick, because pipes leading from cylinders to HA block are quite large (unlike pipes, leading to the height corrector).

[RichardW]

Mine certainly jumped up in the air quick as it got to normal height. Sometimes seems to do it going down as well. I reckon hydraflush and new hydractive spheres should go a long way to sorting it.

[sbraud]

Finally got around to fixing this problem at last.
I diagnosed the front Hyractive block electro valve as being at fault, after reproducing reduced noise/affect with suspension on min height and engine off and opening door. As soon as door was opened “thud” noise from front block and very slight rise in height.
It seem this setup is peculiar to Hydractive II fitted to VSX Xantia/XM (please correct or add if you know of more)
Electro Valve is represented by figure 4 in diagram below



Procedure:
Depressurise hydraulics.
Access on my model was best with air intake/filter box removed.
Identify reservoir feed and disconnect.
Undo and remove hose clip and hose on top of Elec valve.
Disconnect electric plug from valve.
Unscrew 16mm top nut with integral LHM feed nipple. (take care not to damage pipe)
If your lucky the whole valve will unscrew by undoing 16mm top. If not this will undo valve innards, which will allow removal of electro magnet unit and valve piston and springs.
If complete removal is necessary (as electro magnet unit seems to be the problem) then the base of the valve can be undone with a 24mm spanner or extended length wrench bit. (a word of caution: The alloy used to make the base is fairly soft and easily `rounded’ with a spanner!! If this happens you may wish to keep old base and use new to rebuild.)
Replace all parts removed, depressurise and check for leaks.
Pictures of valve breakdown:-



Cheers
Steve
Ps. Thanks Richard for the parts [;)][:D]

[ActivaV6uk]

This system is also on the Activa, do you mind if I (or you, if you have time) write this up and it gest put on the www.activanet.co.uk website?
Thanks
Andy

[sbraud]

Hi Andy.
I dont mind submitting a post on Activanet – no problem! It will give me a chance to use my Activanet BB user account [;)][:)]
Cheers
Steve
Ps. A couple of us Forum members are working on making the official Citroen training manuals for Xanta/XM Hydractive I, II and Activa suspension on the web. Hopefully soon as I think this stuff is gold dust!

[RichardW]

Steve,
Glad to see you got it sorted in the end. Mine is still errant, I've done 13k miles in it since I got it just before Christmas, but just no time to fix it - heopfully I'll get to it in June! The main symptoms on mine are sinking rear when switched off, occasional height jumps, front running too high, so harsher than it should be, er and some more. Plan to lube and free off the height correctors and hydraflush and then see where I am at.
To further your knowledge, only the VSX / Exclusive and Activa had Hydractive suspension. Lower spec models had a similar set up to the BX (mechanical only). The electrovalve and hydractive block you repaired are only fitted to hydractive equipped cars. The function is to split the springing between 3 spheres on each axle, which means that if the computer decides you are working the car hard it can isolate the 3rd sphere, thus hardening the suspension up, and reducing body roll. This means you have the advantage of 'Sports' suspension when you need it (ie when going round corners), but you don't have to put up with the inferior ride for the 95% of the time you don't need it, and can enjoy the smooth ride Citroen is famous for. In fact, the hydractive should have a softer normal ride than a normal Xantia, as it stiffens up for the corners, so no compromise on flat behaviour to make it corner! The switch inside doesn't turn the hydractive on and off BTW, it merely changes the parameters at which the car changes into hard mode - earlier in 'Sport' mode.
The Activa extend the hydractive behaviour by adding active roll control, so the body is REALLY flat in corners!

[sbraud]

Hi RichardW,
I’d be interested to know your findings when you get around to sorting yours.
Thanks for the info. Since original cry for help some months ago I’ve been on a steep leaning curve concerning Citroen hydro pneumatics (Hydractive I, II & Activa). It’s a whole sub-culture! I’m no expert but learning. The more my Xant breaks the more I learn! Whether I want to or not… [;)]
Cheers
Steve

[FrenchLeave]

Well done, Steve. Don't you love it when it all comes right? You must be a qualified Ace of the Base now.

[bernie]

<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by sbraud</i>


Procedure:
Unscrew 16mm top nut with integral LHM feed nipple. (take care not to damage pipe)
If your lucky the whole valve will unscrew by undoing 16mm top. If not this will undo valve innards, which will allow removal of electro magnet unit and valve piston and springs.
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
There is unfortunatly a third option[:(]
The body of the electro valve snaps cleanly in half[}:)][xx(][:(]
Guess which happened to me?