Xantia: Bouncy back end

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RoadkillUK
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Xantia: Bouncy back end

Post by RoadkillUK »

Before I start, I'd like to say that I've already done a search with no real help.
The back end of my Xantia is very bouncy, it drops down during acceleration and rises during braking, I understand that it is meant to do this a little but this is to excess. Also during driving the back end drops by about an inch or so, I know this because when I stop at lights and junctions, after about 10-15 seconds the back end rises.
Recently I have replaced all 3 of the spheres at the back and this is when it started to do this.
Any help please?
P.S. It's not Activa.
'98 new shape
1.9TD
citronut
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Post by citronut »

may be you have been sold wrong spheres
regards malcolm
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Mandrake
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Post by Mandrake »

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

Before I start, I'd like to say that I've already done a search with no real help.
The back end of my Xantia is very bouncy, it drops down during acceleration and rises during braking, I understand that it is meant to do this a little but this is to excess. Also during driving the back end drops by about an inch or so, I know this because when I stop at lights and junctions, after about 10-15 seconds the back end rises.
Recently I have replaced all 3 of the spheres at the back and this is when it started to do this.
Any help please?
P.S. It's not Activa.
'98 new shape
1.9TD
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
It would help if you told us more about the car - for example is it an estate or hatch back ? (They use different spheres at the back) And is it Hydractive 2 or standard ?
Also if you can post the sphere pressures (2 digit number stamped onto the sphere near the filler plug) and the part number (a long number printed in black) then people will be able to tell you if you have the right spheres or not.
Two likely possibilities for it being too soft and bouncy at the back -
(a) 40 bar spheres intended for the estate model have been fitted to the back of a hatchback, instead of the correct 30 bar ones. This will make the suspension VERY soft, so that it will completely bottom during acceleration. Make sure that the rear corner spheres are 30 bars.
(b) If the car is a hydractive 2 model, and the rear spheres for the STANDARD model are fitted to the rear corners, it will be too soft and bouncy as the damper holes will be too big. The damper holes on the rear hydractive spheres should be 0.6mm, the standard model is 1.1mm or 1.2mm. The only way you can tell this would be to remove the sphere and try inserting a small drill bit into the centre hole to find out the size, or post the part numbers of the spheres (in black) here, as there are a couple of people that have access to the part number lists who can look it up for you.
By the way, if the back of the car lifts a lot during hard braking, this could be a sign that your rear brakes are not working properly - try bleeding them and checking the pad/disc surfaces, as the rear brakes cause an anti-dive action with the trailing arms if they are working...
Regards,
Simon
RoadkillUK
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Post by RoadkillUK »

These are the spheres that I bought for my Xantia.
'98 New shape Xantia, 1.9TD, Hatchback.
N45366 SPHERE-REAR XANTIA 1.816V/1.9TD/2.0/HDI
N45372 ANTISINK SPHERE-REAR XANTIA ANTI SINK (EXC ACTIVA)
Next job is to bleed the rear brakes and check the wear in the rear brakes. Would have done that already but I've spent what time I've had today replacing the drivers door window after some scrote decided they'd see if there was anything in the car.
Thanks for the reply.
RoadkillUK
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Post by RoadkillUK »

Sorry, I believe the suspension is standard, it's certainly not Activa.
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Post by jeremy »

Have you done 'Citroebics?' - Raise and lower the car several times to expel air and gas from the hydraulic lines.
Jeremy
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Post by Mandrake »

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

Sorry, I believe the suspension is standard, it's certainly not Activa.
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
There are three versions of the suspension - not two.
Standard - also known as Hydropneumatic, one sphere per wheel, plus an accumulator sphere mounted on the engine, and (in later models) an anti-sink sphere mounted in the middle of the rear suspension chassis member ahead of the fuel tank - the anti-sink sphere has NO effect on the ride quality, nor does the accumulator.
Hydractive 2 - in addition to the above, there are two extra "centre" spheres. The one at the front is mounted down near the bottom left corner of the radiator on a small block. (Not to be confused with the accumulator which is also nearby on the engine) The one at the rear is mounted diagonally to the right in front of the spare wheel carrier, and to the right of the anti-sink sphere.
A sure way to tell if you have hydractive 2 is to measure the diameter of the hydraulic pipes going to the suspension strut tops - standard model uses a steel pipe of about 2.5mm, while Hydractive 2 has a 10mm diameter pipe with a flexible hose joint bolted to the side wings.
Activa - the Activa has ALL the same items as the Hydractive 2, and in addition has yet TWO MORE spheres, I'm not sure where they're mounted, however an easy way to tell an activa is remove the front wheels and look at the rollbar droplinks - on a Standard or Hydractive 2 both sides will be a standard steel droplink bar, while on the activa ONE of them will be a hydraulic ram with hoses coming out of it. (Not sure what side its on, the right I think)
<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">
These are the spheres that I bought for my Xantia.
'98 New shape Xantia, 1.9TD, Hatchback.
N45366 SPHERE-REAR XANTIA 1.816V/1.9TD/2.0/HDI
N45372 ANTISINK SPHERE-REAR XANTIA ANTI SINK (EXC ACTIVA)
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
Ok well the anti-sink sphere doesn't affect the ride, and can't be mixed up anyway due to the unique pipe fitting it has, which leaves the N45366, which is the correct sphere for a Standard model, but NOT a Hydractive 2.
So if you do indeed have the standard suspension, you have the right spheres, if you have Hydractive 2 you have the wrong spheres and it will be too soft.
If you try doing a "bounce test" on the rear suspension, how does it behave ? If its at normal height you should be able to give it a good shove and it should go down 3-4 inches, and then return without overshooting. If there is a lot of overshoot there could be a problem.
Regards,
Simon
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Post by jeremy »

An accumulator sphere will fit a suspension strut and has no damping at all! - but they are readily recognisable as having no valve assembly in the threaded neck - just a tube. Suspension spheres seem to have a flat plate in the mouth of the neck - this is the face of the damper assembly.
Jeremy
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