Citroen C5 X7 mk3 hydractive suspension (updated after fitting new spheres)

[Y Cymro]

You can check whether the EVs are switching from Firm to Soft, by doing a bounce test
If no difference between the two tests, then either
- centre spheres lack gas
- EVs not operating correctly
- a suspension ECU fault, which should trigger a dash warning, and show up on Lexia.

Ok, have done this a few times and note that when pressing on the front wing (it’s a Tourer so I’d need a step ladder to press the back!) it’s possible to bounce it a couple of cms quite easily, and there’s no difference whether the engine is off with the car being left for a while, or whether the engine is running in either standard or sport mode.
There are no dash warning lights on. Possibly suggests a problem with either the centre spheres or somewhere with the EVs.

[Y Cymro]

Diagbox will provide you with electrovalve operation on the live data. I suspect it is your 3 centre spheres that may need replacing - as previously mentioned - if these are end of life then you will get a hard ride as you are only riding on the corner spheres. Whether all 3 centre spheres are gone (2 rear and 1 front) we won't really know. However, we can't discount the hydraulic block at the rear either. The electrovalve here can become stuck (plenty on this on C6 Owners) and I've done a post somewhere on it I think.

But as far as the X7 is concerned - you will notice an immediate difference when engaging SPORT mode on the Hydractive III+ system as fitted to the C5. it is instantaneously noticed while driving if you manually switch it on - so should be very obvious. If you are not getting that feeling, then you may well be partly in that mode if some of the centre spheres are or have failed. I would be inclined to hope it would be these rather than the block.

Hi Marc, thanks for your detailed reply.
When I purchased my car 3 1/2 years ago there was a noticeable difference between standard and sports even when driving down a road and switching between modes but the suspension has become firmer as time has progressed and now it’s always firm and there’s no difference between modes when driving along.
Following Chris’s advice above I performed a bounce test but out of convenience only on the front. As stated, there was no difference whichever mode the suspension was set to. To test the hydraulic block you mention I’ll pop out and raise the tailgate and bounce around in the back to see if there’s a difference at that end. Should give the neighbours something to laugh about if nothing else!

[Y Cymro]

So using Chris’s bounce test on the front and rear I can confirm that I can press down either front wing or the tailgate lip about 35mm easily by hand, and there’s no difference whether the engine’s off with the car being static for a while, or with the engine running in either standard or sport suspension mode.
When driving the ride comfort is much harder than it should be, and as far as I remember, is harder than it once was in sport mode. It’s done 85k miles - which I don’t think is high for the vehicle - and has four new outer spheres.

I’d be prepared to pay another £300 to replace the 3 remaining central spheres, but trying to eliminate any other potential issues or future surprises first.

I remember Marc publishing the ride heights on another thread.

viewtopic.php?t=54260

so I’ll measure mine to see how they compare against my car.

[Y Cymro]

It’s difficult enough finding somewhere flat and level in South Wales to measure my ride heights, and to make it worse it’s just started snowing again so I’ll postpone laying on the floor to measure the heights as described by Citroen.

Measuring from wheel centre to the wing vertically above, I measure
Front =410mm
Rear =395mm

Which is close to the figures measured previously by Marc on his car

Front centre to wing = 41.5 cm
Rear centre to wing - 40 cm

The rear difference is probably because mine’s a Tourer. Importantly, it looks ‘right’ and level, and stays level however much it’s loaded.

[white exec]

Marc -
Are we able to hear the HA3+ FF and RR EVs buzzing when energised, and clicking off - as we would on HA2 ?
Would be good to confirm that the EVs are working, before replacing the 3 spheres.
Chris

[GiveMeABreak]

I only used Diagbox to check this on the live data from the BHI and suspension ECU which shows the operation. I don't think I ever recalled hearing any of the electrovalves energising on this system which is quite different in operation to the previous systems and certainly IIRC Sport mode

There are may actuator tests and data that can be obtained - but the relevant ones here regarding the front and rear electrovalves are the following two - but need to be tested whilst driving as you won't be able to feel the difference when they are switched in and out - so the live data needs to be captured whilst driving / the actuator test triggered by a passenger as sport mode is switched in and out really.

Parameter Title	Details of the activation (Duration, frequency, cycle)	Associated message
Front hydractive electrovalve	Control the front hydractive solenoid valve. Check that the front suspension becomes firm (duration of 15 seconds)	Check that the front suspension changes from the soft status to the firm status
Rear hydractive electrovalve	Control the rear hydractive solenoid valve. Check that the rear suspension becomes firm (duration of 15 seconds)	Check that the rear suspension changes from the soft status to the firm status

[Y Cymro]

Parameter Title	Details of the activation (Duration, frequency, cycle)	Associated message
Front hydractive electrovalve	Control the front hydractive solenoid valve. Check that the front suspension becomes firm (duration of 15 seconds)	Check that the front suspension changes from the soft status to the firm status
Rear hydractive electrovalve	Control the rear hydractive solenoid valve. Check that the rear suspension becomes firm (duration of 15 seconds)	Check that the rear suspension changes from the soft status to the firm status

Does this mean there’s a separate ‘sport’ EV at the front and another for the rear, in which case if a single EV failed it would affect only front or rear separately?

On mine, both front and rear suspension is stiff, and pressing the sport button makes no difference at either end. I wonder is there another control system or EV which activates both front and rear?

I only used Diagbox to check this on the live data from the BHI and suspension ECU which shows the operation........... but need to be tested whilst driving as you won't be able to feel the difference when they are switched in and out - so the live data needs to be captured whilst driving / the actuator test triggered by a passenger as sport mode is switched in and out really.

I can discern no difference whether the sport switch is pressed or not, nor can I tell a difference in suspension harshness when driving along. For simplicity, if I connected to Lexia (which I don’t have) with the car stationery, would I be able to see on-screen that the EVs have switched in or out, as suggested in the above table?

[GiveMeABreak]

Hi Steve

Yes, the electrovalves are contained in the front and rear hydraulic blocks - these switch in and out the front centre and 2 rear centre spheres.

The reason a test drive is required is because although the actuator test will be able to confirm that the electrovalve has been energised, it does not follow that it has actually moved - because they can 'stick'. So the actuator test will confirm a power supply to the valve, but not that it has actually budged if that makes sense.

LEXIA/PROXIA title (*)	Unit	Value	Parameter statuses
Front suspension travel	Step	-	XXX
Speed of front suspension travel	Mm/s	-	XXX
Longitudinal acceleration	"g"	-	X,XX
Lateral acceleration	"g"	-	X,XX
Engine speed	Tr/mn	-	XXXX
Steering wheel speed	° / sec	-	XXXX
Steering wheel angle	°	-	XXX
Sportiness of roll	/100	-	XXX
Sportiness of ride	/100	-	XXX
Sportiness of pitch	/100	-	XXX
Hydractive status	N/A	0	Soft
Hydractive status	N/A	1	Closed
Accelerator throttle speed	%/20ms	-	XXX

Some other tests, which will show the values in the table for the relevant conditions whilst driving.

LEXIA/PROXIA title (*)	Value	Parameter statuses
Cause: changing between firm / soft	0 1 2 3 4 5 6 7	Travel – pulldown Travel – release Steering wheel angle Steering wheel speed Pressing of the accelerator Releasing of the accelerator Acceleration Deceleration
Road conditions	0 1 2	Main road: NORMAL Poor road Impacts: road wheels
Height correction status	0 1	Rest Controlled

(*) The height cannot be corrected when the hydractive is at the firm status

[Y Cymro]

Hi Marc
Thanks for the information.

When I purchased the car there was an obvious difference in ride quality between when sport mode was off or on. Now, I can feel no difference at front or rear whether sport is activated or not. Therefore, I’m wondering what could be affecting all 4 wheels to make the suspension firm. For example, if either front or rear hydraulic block became sticky, then I would expect only one end to be affected rather than all corners. The sport switch receives power (the warning light illuminates) but I wonder what component does the switch power up which in turn activates the front and rear hydraulic block?

There is movement in all four corners of the suspension when I do a bounce test, but it’s firmer when driving along - more like a normal car
Many thanks

[white exec]

I think you've got to choose between getting a thorough diagnostic run, and an investigation into whether the two EV/regulators are actually operating — and just fitting a set of new centre spheres. The full investigation won't be cheap, and needs to be done by someone who knows Citroen hydraulics and the suspension ECU well, and what to look for.

A cheaper alternative might be just to fit one new centre sphere at the front, and see whether that restores softness at the front end. If it does, do the back pair.

Marc - I notice that the HA3+ regulator EVs have a pressure-relief screw. Do these ever need bleeding?
Pretty sure these EVs must click/hum, even if quietly. Are they pull-in then PWM fed, like HA2? Listening-stick check?

[GiveMeABreak]

No bleeding necessary from these Chris. It's all done automatically - but after any depressurising / drain / re-fill / Re-pressurising, the bleeding is done just by setting to lowest suspension level, and slow turning of the wheel lock to lock 8-10 times without holding at either stop. Then check fluid is between marks and no bubbles / repeat procedure if necessary, then return to normal height.

Here's a simple diagram of the rear firmness regulator:

Soft Status

"A": High pressure inlet (Integrated BHI ).
"B": Return to the reservoir (Integrated BHI ).
(1) Rear firmness regulator.
(2) Rear stiffener regulator accumulator.
"a" Variable firmness electrovalve.
"b" bleed screw(s) .
"c" Hydraulic isolation slide valve.
"d" Electrovalve slide valve.

Soft status:

• The electrovalve is not supplied
• The electrovalve slide valve "d" moves under the effect of the integrated hydroelectronic block supply pressure
• The return to the hydraulic fluid reservoir is blocked: The pressure under the lower part of the hydraulic isolation slide valve is identical to that of the BHI
• The upper part of the hydraulic isolation slide valve is identical to that of the BHI: The slide ("c") moves under the action of the integral spring
• Flow of hydraulic fluid between the right hand and left hand suspension is possible: The hydractive 3+ sphere communicates with the suspension circuit

N.B.: In the rest position, the rear firmness regulator is at the soft status.
N.B.: The body height can be regulated in "soft status" operation.

Firm Status

"A": High pressure inlet (Integrated BHI ).
"B": Return to the reservoir (Integrated BHI ).
(1) Rear firmness regulator.
(2) Rear stiffener regulator accumulator.
"a" Variable firmness electrovalve.
"b" bleed screw(s).
"c" Hydraulic isolation slide valve.
"d" Electrovalve slide valve.

Firm status:

• The electrovalve is supplied
• The electrovalve slide valve "d" moves and frees up the return to the reservoir and blocks the hydraulic supply from the integrated hydroelectronic block
• The bottom part of the slide ("c") is at the pressure of the hydraulic fluid reservoir
• The upper part of the slide valve is under pressure from the hydractive sphere 3+
• The difference in the pressure at each end of the slide ("c") causes its movement
• In its new position the slide ("c") blocks the passage of hydraulic fluid between the RH suspension and the LH suspension
• The hydractive 3+ sphere is isolated from the suspension circuit

[Y Cymro]

Decided to chance changing the front centre sphere and booked the car into my local dealer Bassets in Swansea. Took the car in earlier this morning and have just been told they cannot remove the sphere due to corrosion and that an extra 4 hours labour will be needed to lower the front subframe to give them more space to get at it. That’s unacceptable so Bassets will give it one more try before I leave. Damn it!

[Peter.N.]

They can get very tight, haven't got hydropneumatic on mine but I ran CX's and XM's and they were a problem, I had to take a hammer and chisel to them on a number of occasions. I made a strap wrench with motorbike chain which was quite effective but the best tool is the one a chap makes on Ebay with a bolt that screws into the side of the sphere, don't know if he still makes them but I still have one form my Mk1 C5 days.

Peter

[white exec]

Spheres do not corrode in - never.
A squirt of plusgas at the joint between sphere and mount might help; never had to do that though.
A tight sphere will need one of the sphere removal tools, or an approximation to one.
Chain/metal strap wrenches rarely work.
A cold chisel (or impact chisel) driven into the sphere perimeter will also work.
They are RH thread, if the workshop is not used to them.
Tighten the new one tight by hand only, not with a wrench.

[Hell Razor5543]

Xaccers has (in his signature) a link to a DIY sphere removal tool. I have used it on Xantias (although VERY tight spheres need percussive sharp impacts (so a hammer and chisel!) to get them moving.

https://www.frenchcarforum.co.uk/forum/ ... hp?t=21850