Lowering of C5

[peterlee]

Did you guys know that C5 suspension height can be lowered? :D

Those of you who are in the C5-L newsgroup in yahoo would have come across the recent topic. It seems that agents with the computer can simply program the drive height of C5. ;)

[peterlee]

Excerpt from C5-L yahoo newsgroup:

> Can any one tell me the correct suspension hight when the car isstood
> on level ground. My C5 has been lowered 25mm after I complained it
> appeared high but it as gone back up on its own 3 weeks later.
> Any ideas?
>

Make sure that it's actually in normal, if your last drive was on poor
roads your C5 may actually have lifted automatically (by 13mm iirc) If
so ,first set it to the high driving position, let it lift, then set it
to normal (could take >min)

Even in order to measure the suspension height, you need access to a
garage lift or a grease-pit. With the engine running in 'normal' the
procedure for measurement front and rear:

- lift the car by hand (not a big amount of force is require to get it
out of neutral position) Let it regulate to normal (measurement 1)
Push the car down by hand, let it regulate to normal (measurement 2)
average the two measurements.

You need to measure from a certain point on the front crossmember
(towards the side) to the ground and from the wheelcenter to the
ground. The average difference should be 140mm +/- 6mm.

At the rear you need to measure from the wheelcenter to the ground and
from the rear crossmember to the ground (close to the mounting bolt
above one of the rear spheres) The average difference should be 73mm +/-
6mm

You will also need access to a garage computer to change the height
setting (IIRC it's between 0-255 but not sure how the increments
respond to height) The maximum adjustment is only 10mm (255=10mm!?)

If the height is more than 10mm off, you need to rotate the cuffs of
the electronic height sensors and then adjust by computer.

[peterlee]

More info, courtesy of the guru's over at C5-L (Paul is so techinally knowledgeable!).

http://www.citroenet.org.uk/miscellaneous/scoop/scoop-02.html

No it won't automatically harden, in fact if you drive in the higher
suspension setting (<40km/h) the computer will enforce "soft-mode",
if you car is equipped with the sports button.

Changing the suspension height will slightly alter the suspension
geometry, but as long as you stay within the prescribed range it
won't go out of spec (camber-caster- toe).

In ride settting or high ride setting (<40km/h) height has nothing to
do with pressure or spring rates, it's only related to the *amount*
of oil between the sphere and the wheel piston, *not the pressure*.

If you lower the car too much, it could bottom out on the rubber
stops on tall bumps, the reverse is true if you set it too high.

In the topmost setting the suspension arms are pushed against the
bottom stop with max pressure(hence virtually no flexibility and
walking pace only)

In the lowest setting the car rests on the top stops (without any
pressure in the struts) therefore maintenance only.

One caveat: make sure that the spheres still have enough pressure, in
200.000km they are allowed to drop about 10%, but once they drop
below a certain level (50%?) they may "self-destruct" . The membrane
is designed to get punctured to protect the valves and the BHI.

[peterlee]

Still on the topic of suspension...

I read from Planete Citroen (www.planete-citroen.com (http://www.planete-citroen.com)) there is a replacement for C5 hydractive spheres which make the ride more comfort-bias... see here http://www.myparts.org/

I.F.H.S. - Intern. Factory of Hydraulic Systems N.V.

Address Z.I. Noord, Klaverbladstraat 2 C
B-3560 Lummen
Belgium
Telephone +32 013 53 19 67
Fax +32 013 53 15 50

Also,
"There is a Dutch supplier who manufactures spheres “comfort” for C5 and other Citroens.
Their solution is extraordinary: my C5 2.2HDI H3+ (thus already definitely more dûr that your H3) became a genuine flying carpet.

Here their N° Such: +31 346 351150

They speak Netherlander as well as English."