Rear end - Not rising!

adzbaby · Post by **adzbaby** » 02 Feb 2005, 21:58

Xantia 1.9 TD, 94 m reg.
The suspension was ok a while back, the rear end would take some time to establish itself at normal ride height - if it had sunk down after few days no use - upon start up.
Now the rear end will not rise from lowest setting to normal ride height, it will rise to highest and go to lowest on command; the front behaves properly and will go between teh 3 heights..
Any suggestions?
Cheers.

Robin · Post by **Robin** » 02 Feb 2005, 22:24

I know not everyone will agree with this but ......
I suspect the height corrector is at fault but these are startlingly reliable units.
Check first - You do need to ensure the linkage from the rear roll bar to the height corrector is both free, connected and well lubricated. If this is seized or disconnected it will still operate on high and low manual settings. I suspect this to be the cause.
Check second - This is the questionable part - make sure the system at the rear is fully bled of air, bleed the rear brakes through thoroughly. Do this with the suspension set on high and the engine running. An assistant to push the brake pedal helps because it is likely to blow the tube off the bleed nipple if yu are a bit energetic. This volume through the system is not all bad, it clears the rubbisg through.
Finally - rear accumulator sphere plays it's part too so just to be certain make sure it's a good one.
After all of that a few rounds of Citearobics with a mug of coffee and the radio on.
Good luck, Robin

Kowalski · Post by **Kowalski** » 02 Feb 2005, 22:33

The "rear accumulator", or anti-sink sphere has little to do with the suspension or anti-sink, it is there solely to provide a reservoir of pressure to operate the rear brakes.
There is a popular misconception that the anti-sink sphere has something to do with stopping the suspension from sinking, it arrived at the same time that Xantias were fitted with anti-sink suspension and was thus dubbed the anti-sink sphere.

bernie · Post by **bernie** » 02 Feb 2005, 23:34

Sounds like the plastic clip has come off.

nick · Post by **nick** » 03 Feb 2005, 00:09

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Kowalski

The "rear accumulator", or anti-sink sphere has little to do with the suspension or anti-sink, it is there solely to provide a reservoir of pressure to operate the rear brakes.
There is a popular misconception that the anti-sink sphere has something to do with stopping the suspension from sinking, it arrived at the same time that Xantias were fitted with anti-sink suspension and was thus dubbed the anti-sink sphere.
<hr height="1" noshade id="quote"></blockquote id="quote">
No disrespect intented, but I'm not totally convinced by this.
Going by what it says in the "The Citroen Technical Guide";
The rear anti-sink valve is connected slightly differently:
in addition to feeding the rear suspension and the brake circuit,
as usual, it connects to an additional anti-sink sphere
as well. The function of this sphere is to maintain pressure
in the braking circuit. As the brake valve is the most leaky element,
it could exhaust the pressure between the piston
and the plunger while the remaining pressure behind the
piston (provided the high pressure and the front suspension
circuits do not leak that much) stays rather high. In this
case the anti-sink valve might open again in error—this additional
sphere ensures that this will not happen.
...I still think a 'flat' anti-sink sphere would cause the rear end of the car to sink faster than one with the anti-sink sphere in good condition, particularly if the brake valve was worn.

AndersDK · Post by **AndersDK** » 03 Feb 2005, 00:20

Nope Nick -
The antisink sphere has only 2 purposes : to maintain a spare pressure for the rear brakes - WHEN the antisink valve has closed and ensure the antisnk valve stays closed.
The way you think it works is the hydractive sphere function - a totally different and independent system.

nick · Post by **nick** » 03 Feb 2005, 00:25

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by AndersDK

Nope Nick -
The antisink sphere has only 2 purposes : to maintain a spare pressure for the rear brakes - WHEN the antisink valve has closed and ensure the antisnk valve stays closed.
<hr height="1" noshade id="quote"></blockquote id="quote">
But if the anti-sink sphere helps to ensure that the rear anti-sink valve stays closed, then surely it follows that a flat anti-sink sphere will allow the rear anti-sink valve to open, therefore allowing the rear to sink ?

AndersDK · Post by **AndersDK** » 03 Feb 2005, 00:27

... IF the pressure otherwise is lost in the rear suspension. Note that the most common leaks are excluded : the HC and the rear brakes circuit.

Dave Bamber · Post by **Dave Bamber** » 03 Feb 2005, 00:57

I'm with Bernie, plastic clip bust or fell off.

ghostrider · Post by **ghostrider** » 03 Feb 2005, 02:30

I'd go with Dave & Bernie too, mine showed very similar tendencies, bought a new clip as the old one was very worn, better but the ball it goes onto on the roll bar side was badly worn as well, so it still tended to fall off over bad bumps or potholes (What on UK roads?[:D] [:D] [:D] [:D] [:D] [:D] ), and the ball is part of an assembly that was around ?85 +VAT, didn't see much point in going to a scrapper, so I cleaned the ball up, lightly greased the socket in the plastic clip and then added Chemical metal, pushed it back on and left it to cure having cleaned off the excess that was squeezed out. It's worked for about 8K so far. One day I'll get round to turning up a new one on the lathe with a threaded end, drilling the old one out and bolting the new one in..........
Pete
________
Vermont medical marijuana

BonceChops · Post by **BonceChops** » 03 Feb 2005, 04:12

My clip has been held on with wire for about 10k miles. It kept falling off so I wired in on at both ends. Bought a new clip but it has never dropped off since so I keep forgetting about it ( please stop reminding me folks )

soupy_sam · Post by **soupy_sam** » 03 Feb 2005, 22:38

what is the CLIP everyone is going on about?

Robin · Post by **Robin** » 04 Feb 2005, 00:20

Sam, the suspension height is governed automatically by a body height control device that takes its datum from a link connected between the anti roll bar and the 'height corrector'HC ( control device).
This 'link' is made up of a number of components and the key element is a plastic part commonly referred to as a clip. Mainly because it clips onto the HC and the fixed part on the anti roll bar.
This link assembly frequently becomes stiff or seized and then locks the body height to the setting it has stuck in.
The cure is a good sparying with a penetrating oil and then a grease up. The height corrector itself is protected by a rubber boot and generally this is quite capable of keeping the dirt out so it is just the link mechanism that is at fault.
There is one at the front and one at the rear. hope this helps, Robin.