Citroen XM Forum

Time to plumb an XM hydractive valve into the front suspension! Have done that on my old Citroens, makes a big difference!

Marc

Tell me more! Id like to be able to have hydractive at the push of a button, not all the time though.

All you need to do is cut into the transverse pipe, plumb in the valve then feed it with power when you want soft mode.
As well as the stiffening effect you also get the advantage of the fluid blocking valve for cornering.

The main benefit is the ball valve in the HA valve that stops crosswise flow when cornering, it cuts the roll angle a lot on old Citroens. What I did was to take the feed from the height corrector to the nearside sphere and plumb it to the HA valve via a 4.5 to 3.5mm union. Then I made two adaptors, with central holes threaded for 4.5mm unions, to screw in the ends of the HA valve in place of the XM ones that usually connect it to the fat suspension pipe going to each sphere on the XM. This enabled me to fit standard 4.5mm pipe from each end of the HA valve to the front suspension cylinders. Fitted an accumulator sphere into the HA valve and bolted it to the front chassis arm.

Did that on both the DS and the SM a few years ago. Huge benefit on the DS - transformation! Suspect it would be same for the CX, but dont have one to try it on. Only thing I've fiddled with since on the DS is blanking off where the electro valve screws in so that the centre sphere can stay in circuit permanently. Smoother still in a straight line, but much better roll control in corners. The SM corners flat. Nice hydraulic solution, no electronics anywhere in sight!

Marc

Interesting, very interesting. You can of course modify the elctrovalve, and leave it permanently open. I have done this on Xms in the past to leave them in permanent soft mode.

I still like the CX roll!!!

Robert it's a while since I did it, but seem to remember when I removed the springs and shuttle in the electrovalve I got some LHM weeping back. Maybe I got it wrong, memory isn't great. Is that the way to get soft mode permanently on an XM? I made an end plug and fitted it with a Dowty washer in place of the electrovalve on my DS.

Worth mentioning that because the older Citroens are sinkers it takes quite a lot longer for the suspension to rise from a cold start with an HA valve in place. Fixing it so it's in permanent soft mode speeds up things noticeably, less restrictive routes through valve during pressure rise. Not sure there are many people on the forum with an old Citroen but it's certainly a worthwhile exercise for a DS if anyone is interested.

Marc

viewtopic.php?f=7&t=1794&p=17952&hilit=ressort#p17952

Check out the above post on putting a Xm into permanent soft mode. There is a leak off return on the back of the electrovalve also.

I wonder what it would be like to fit this to the CX, but part of the fun of driving it is the mean body roll!

But at least anything not bolted down wont fall out of the windows when you go round corners!