Hi
My 93 VSX 1.9 Td has developed a fault,Car starts and rises to normal level,on moving off the rear suspension dips about 3-4 inches (also if brake applied soon after moving ) then recovers and may not do it again all day, just when moving off after leaving the car and the suspension has "sunk"
I think and have been told it may be the accumulator sphere at the rear.
If so what type is it as my VSX has a button near the ride height adjuster for sports mode , does this make it an activa ? can any tests be suggested to test for the accumulator failure.The car has failed its MOT on this and it is off the road....
regards...Paul
Xantia VSX TD rear suspension fault
Moderator: RichardW
Your VSX Xantia is a Hydractive suspension model - meaning it has an extra center sphere front & rear. The sports button shifts the parameters for the ECU to decide when to operate suspension in sports/normal drive mode.
However the rear accumulator sphere you are referring to is the anti-sink system sphere. This also serves as the rear brakes accumulator sphere when the hydraulic system pressure for any reason is lost.
The Activa model is the later special active-anti-roll system Xantia. This is an extra system besides the hydractive suspension and anti-sink.
Its the hydractive rear center sphere that can cause the rear suspension symptoms you have. When this sphere is close to being flat, there will be just enough pressure left to press out the hydraulic fluid from the chamber when system at rest - but no pressure left to prevent the chamber being filled with hydraulic fluid once the valve opens. Then the sphere can drain the system with as much as almost 400mL of the hydraulic fluid. Hence the drop in suspension height.
However the rear accumulator sphere you are referring to is the anti-sink system sphere. This also serves as the rear brakes accumulator sphere when the hydraulic system pressure for any reason is lost.
The Activa model is the later special active-anti-roll system Xantia. This is an extra system besides the hydractive suspension and anti-sink.
Its the hydractive rear center sphere that can cause the rear suspension symptoms you have. When this sphere is close to being flat, there will be just enough pressure left to press out the hydraulic fluid from the chamber when system at rest - but no pressure left to prevent the chamber being filled with hydraulic fluid once the valve opens. Then the sphere can drain the system with as much as almost 400mL of the hydraulic fluid. Hence the drop in suspension height.
Anders (DK) - '90 BX16Image
If the sudden drop in height occurs well after the suspension has risen to the normal ride height, it could also be a sticking rear electrovalve, but I would check the other cheaper options like spheres first...
Regards,
Simon
Regards,
Simon
Simon
1997 Xantia S1 3.0 V6 Auto Exclusive in Silex Grey
2016 Nissan Leaf Tekna 30kWh in White
2011 Peugeot Ion Full Electric in Silver
1977 G Special 1129cc LHD
1978 CX 2400
1997 Xantia S1 2.0i Auto VSX
1998 Xantia S2 3.0 V6 Auto Exclusive
1997 Xantia S1 3.0 V6 Auto Exclusive in Silex Grey
2016 Nissan Leaf Tekna 30kWh in White
2011 Peugeot Ion Full Electric in Silver
1977 G Special 1129cc LHD
1978 CX 2400
1997 Xantia S1 2.0i Auto VSX
1998 Xantia S2 3.0 V6 Auto Exclusive
Hi Paul -
Removing Citroen spheres is best done in 2 steps :
1) crack the binding seal - which makes the sphere stick - sometimes like its welded on. This is done by unwinding the sphere maximum 1/4 turn (ccw - normal thread) - while full system pressure is applied.
The full system pressure is obtained when engine is idle (and thus hyd pump working) and suspension height set to maximum.
Dont unwind more than 1/4 turn - or the hydraulic fluid will start weezing out like a Tomcat
2) Removing the sphere with any system pressure relieved. This is done by setting the suspension to lowest setting - while engine idle - and then further wait a couple of minutes.
Unwind the pressure relief valve - located on the Pressure Regulator (the device which holds the main sphere located on gearbox flange). This valve is a 12mm head bolt - head protruding the PR like its not totally winded up. Its the ONLY 12mm headbolt in that area - you cant miss it if you take a 12mm ringspanner in your hand.
Unwind this valve bolt by max ½ turn. You can hear the pressure is now released by the hissing from the fluid escaping to the reservoir.
Stop the engine.
NOW - and only now - you can unwind/replace the sphere(s) in question.
Re-fitting the new sphere is much easier (NO - not the reversal of the ....) :
Be sure you have a new square section seal with your new sphere. The old one may be re-used when cleaned. Grease the seal and fit it into the recess on receiver of the sphere - IMPORTANT ! - NOT to the sphere.
Tighten the sphere by hands only - like you do an oil filter.
When all spheres done :
Tigthen the pressure release valve (12mm bolt) - never torque it.
Set the suspension height to normal. Start the engine and let suspension settle. Then do the Citaerobics (full up/down cycles with suspension height) to vent the hydraulics side of the suspension.
Notes :
The rear antisink sphere is identified by having a single 3.5mm pipe connected to center of sphere base.
The hydractive axle center spheres are identified by the large dia (10mm) pipes running from base to each wheel on axle.
The wheel suspension spheres are self explanatory - fitted directly to the wheel cylinder each corner.
The main (or system) accumulator sphere is the only sphere ever found located directly on the engine/gearbox assembly.
Its IMPERATIVE you get the correct sphere according to model spec/engine type & size/chassis type/axle/function.
This makes for an incredible amount of different sphere types - and only one type fits the one you have removed. Spheres cannot be modified. They are factory set with cubic capacity/inflation pressure/damper (shocker) calibration and damper orifice.
Removing Citroen spheres is best done in 2 steps :
1) crack the binding seal - which makes the sphere stick - sometimes like its welded on. This is done by unwinding the sphere maximum 1/4 turn (ccw - normal thread) - while full system pressure is applied.
The full system pressure is obtained when engine is idle (and thus hyd pump working) and suspension height set to maximum.
Dont unwind more than 1/4 turn - or the hydraulic fluid will start weezing out like a Tomcat
2) Removing the sphere with any system pressure relieved. This is done by setting the suspension to lowest setting - while engine idle - and then further wait a couple of minutes.
Unwind the pressure relief valve - located on the Pressure Regulator (the device which holds the main sphere located on gearbox flange). This valve is a 12mm head bolt - head protruding the PR like its not totally winded up. Its the ONLY 12mm headbolt in that area - you cant miss it if you take a 12mm ringspanner in your hand.
Unwind this valve bolt by max ½ turn. You can hear the pressure is now released by the hissing from the fluid escaping to the reservoir.
Stop the engine.
NOW - and only now - you can unwind/replace the sphere(s) in question.
Re-fitting the new sphere is much easier (NO - not the reversal of the ....) :
Be sure you have a new square section seal with your new sphere. The old one may be re-used when cleaned. Grease the seal and fit it into the recess on receiver of the sphere - IMPORTANT ! - NOT to the sphere.
Tighten the sphere by hands only - like you do an oil filter.
When all spheres done :
Tigthen the pressure release valve (12mm bolt) - never torque it.
Set the suspension height to normal. Start the engine and let suspension settle. Then do the Citaerobics (full up/down cycles with suspension height) to vent the hydraulics side of the suspension.
Notes :
The rear antisink sphere is identified by having a single 3.5mm pipe connected to center of sphere base.
The hydractive axle center spheres are identified by the large dia (10mm) pipes running from base to each wheel on axle.
The wheel suspension spheres are self explanatory - fitted directly to the wheel cylinder each corner.
The main (or system) accumulator sphere is the only sphere ever found located directly on the engine/gearbox assembly.
Its IMPERATIVE you get the correct sphere according to model spec/engine type & size/chassis type/axle/function.
This makes for an incredible amount of different sphere types - and only one type fits the one you have removed. Spheres cannot be modified. They are factory set with cubic capacity/inflation pressure/damper (shocker) calibration and damper orifice.
Anders (DK) - '90 BX16Image