Xantia F. suspension drops from max height - FIXED

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sbraud
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Xantia F. suspension drops from max height - FIXED

Post by sbraud »

Update: Fix towards end of post... [:)]
Steve
24 May 05 - E. Valve Pics at last! (end of post)
...........
OK one day I’d like to offer some help instead of asking for it, but until then… [:I]
My 2.0/16v VSX ‘95 has a problem staying up… let me explain. When I put suspension height to maximum and allow car to level-out on full height and then switch off ignition, the front drops down to around normal drive height. There is also a thud noise, which I can only describe as a valve/sphere/until unable to hold pressure and giving way. When I restart engine second time, lever still in max, and allow car to level-off at max and switch off again it drop, but not at far this time. On the third occasion she stays put in maximum height, and will stay that way, all day if need be. [V]
Equally, when I put car in minimum height, it’s the same in reverse. Allow it to settle at minimum, switch off and she pops up to normal height with same thud noise. Repeat three times and she stays at minimum.
The back end is behaving.
All this when cold. After a good drive the drop or raise is less pronounced but still there. Hydraulic pressure regulator ticks every 20 to 25 sec on average.
So far I’ve changed : Front anti-sink valve (under reservoir)
Both front damper spheres
Accumulator sphere
Anti-sink sphere (electric unit that hums when doors are opened)
New greeeeen LHM
I’m thinking of changing hydraulic pressure regulator next… The one next in-line after pump with accumulator sphere, but thought I’d run it past you guys because at this rate I’ll be broke and my Xant will virtually have new front hydraulics still with this problem.
Cheers
Steve
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Post by Kowalski »

Have you tried giving the system a good hydraflushing?
Buy 5 litres of the stuff, put in in and leave it for 1000 miles, then refill with LHM.
sbraud
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Post by sbraud »

Cheers Kowalski,
I've given it some thought, but the thud noise from front when car drops or raises sound like something mechanical not holding pressure… but yes, I may have to try a hydraflush just to eliminate it from my list of possibles.[;)]
Thanks
Steve
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Post by AndersDK »

Steve -
You dont mention any problems during drive, or start, with height in normal ?
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Post by dnsey »

presumably having replaced all those bits you've bled the system?
Just in case...:-)
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Post by sbraud »

Thanks AndersDK,
Good point... From cold, in the first couple of mins of driving initially there's noting noticeable with height in normal. Car feels normal in every respect. Start-up has no pop-up or drop but after a short drive if you rev engine 3000rpm or so, front suspension pops up - stationary or not. Then shortly afterwards sinks back to normal level. Noticed this one waiting at light just outside work, but only after short journey. After 5 miles or so symptoms seem to disappear and all seems normal as car warms up.
Also I can drive the 25 miles home and switch off and suspension stays put in normal height, as it should. Leave it 5 mins or so, restart engine and then switch off shortly afterwards and front sinks very slightly 2-5mm approx (this seems to be intermittent)
Cheers
Steve
<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by AndersDK</i>

Steve -
You dont mention any problems during drive, or start, with height in normal ?
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
sbraud
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Post by sbraud »

Cheers dnsey,
Well lets just say until I discovered this forum the only point of reference I had was the Haynes book of lies...
I've been using it's recommended bleed procedure: ``drop the height lever inside the car, with the engine running, slacken the 12mm bleed screw on pressure regulator after car settles until `whistling stops’ then retighten screw…
But I've since seen on here some variations: same as above with door/boot open…
And also: when the suspension needs to be bled,the lever in the car needs to be at the [?]highest[?] position,engine running at idle,undo the "bleed screw" 1/4 turn,leave about 3 minutes and then tighten(NIP ONLY) the bleed screw.then lower the lever to its normal position,the suspension is now bled correctly!!.
So it's possible I've been doing it wrong all these years... the story of my life. [;)]
Thanks
Steve
<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by dnsey</i>

presumably having replaced all those bits you've bled the system?
Just in case...:-)
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
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Post by Richard Gallagher »

Just a thought here, is this happening with the front wheels in the straight ahead position or on 'lock'?
The reason I mention this is that a 'quirk' of Xantias is that when stationary and the steering is set roughly halfway (or beyond) to full lock, the suspension will quickly jump from high to low repeatedly.
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Post by sbraud »

Thanks Richard,
Yep I've been caught out with that one in the past. I’m aware of the quirk [:p], but it happens in straight ahead position. Drop or pop-up, as first described, is when car is stationary as well as moving.
Cheers
Steve
<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Richard Gallagher</i>

Just a thought here, is this happening with the front wheels in the straight ahead position or on 'lock'?
The reason I mention this is that a 'quirk' of Xantias is that when stationary and the steering is set roughly halfway (or beyond) to full lock, the suspension will quickly jump from high to low repeatedly.
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
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Post by AndersDK »

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

Thanks AndersDK,
Good point... From cold, in the first couple of mins of driving initially there's noting noticeable with height in normal. Car feels normal in every respect. Start-up has no pop-up or drop but after a short drive if you rev engine 3000rpm or so, front suspension pops up - stationary or not. Then shortly afterwards sinks back to normal level. Noticed this one waiting at light just outside work, but only after short journey. After 5 miles or so symptoms seem to disappear and all seems normal as car warms up.
Also I can drive the 25 miles home and switch off and suspension stays put in normal height, as it should. Leave it 5 mins or so, restart engine and then switch off shortly afterwards and front sinks very slightly 2-5mm approx (this seems to be intermittent)
Cheers
Steve
<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by AndersDK</i>

Steve -
You dont mention any problems during drive, or start, with height in normal ?
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
Right - IMHO you should certainly first off chase the oddities in normal drive height. Any problems found in the extreme height settings would be more or less academic to trace down.
I have a few comment on this :
Since the height pops up - or down - on front only, you can rule out the components which are common to the brakes, servo, and rear suspension height.
The suspension spheres does not have any influence on height - only on ride softness - and the front suspension cylinders can only dump the pressure thru the HC's open return path. This narrows you down to a few possible problems on the front suspension :
1) the HC itself. Caused by dirt it may partly stick, thus suddenly change position.
2) the HC mechanical linkage certainly can give same symptoms as above
3) the front antisink <font color="red"><b>valve</b></font id="red"> - <b>if present on your model</b> - may have intermittent function. This valve works on system pressure differences only - no electric signals. It's known to pack up on earlier models.
The hydractive valve block / sphere can not cause these symptoms as these components do not influence the height - only drive softness.
The pressure regulator <font color="red"><i><b>MAY</b></i></font id="red"> be at fault admitting too high a system pressure output, but then it would not likely give the normal 30sec's ticking.
Since you have the ticking from the regulator, you know the pump supplies a pressure of at least some 170-180 bar, and then it works.
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Post by sbraud »

Thanks Anders and sorry not to reply sooner – mad week![:p]
I’ll get underneath this weekend and check out that front H/C (don’t panic All, I’ve got the use of a pit so shouldn’t kill myself – no promises [:D]). To be honest I hadn’t given it a second thought but it makes sense… at worst if only to eliminate it from my list.
I’ve already changed front anti-sink valve, some time ago, to no avail. Also, I’m going to replace Pressure Reg, as mine has a very slow leak, it seems – probably not helping!
Anyway I’ll pass on any triumphs/failures.
Thanks All
Cheers
Steve
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Post by RichardW »

Steve,
The 97 Xantia VSX I have just acquired has similar symptoms... I changed the accumulator on Friday, then was playing with the height afterwards to bleed it out a bit. From low-normal comes up OK to about normal height, then suddenly springs up in the air about 1" front and rear [8)] before settling back to 'normal' (Used advisedly as the front appears to be running too high.) I also get some loud clicking (sounds quite like your thudding) from around the engine that is not the pressure regulator and seems to be assocciated with the hydractive. I am going to hydraflush (the LHM that came out of the PR when I changed the accumulator was pretty shot) and try a new front hydractive sphere (looks original) and see what happens then. Curious, but definitely a challenge to be solved! Since we have 2 'similar' cars, it is probably not unknown generally, so maybe a call to Pleaides is in order?
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Post by sbraud »

Hi Richard.
Ummm interesting…
Could there be a slight difference in VSX Hydractive set-up and other Xants? I know it’s weak… but I have to admit I’m foxed.
Cheers
Steve
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Post by sbraud »

Saw this on another post...
<i>Tried Citronome in Derby? I have a feeling they might be able to check the Activa suspension ECU.. I think they can check normal hydractive ECU's. I asked when I thought mine wasn't working - new spheres fixed that!
Quote from their site...
XM & Xantia Hydractive Suspension
We are fully equipped and experienced in the diagnosis and repair of <u>hydractive</u> supension systems fitted to XM and Xantia <b><u>VSX</u></b> and active roll correction systems fitted to Xantia Activa. Briefly, these systems <u>differ from the standard hydro-pneumatic suspension by the presence of an electronic control unit and additional sensors and hydraulic components</u>.</i>
Is there really a difference between VSX and non-VSX regarding hydraulic control unit or the alike? I was wondering because I noticed when all was fine with suspension, there was some drop-down in height when you put your foot down!
I only mention this as RichardW has a VSX and similar problems too..
Anyone know or have details?
Cheers
Steve
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Post by alexx »

I have to slightly correct Anders' explanation above. It's true that in theory hydractive blocks do not influence the height. But they COULD, if something is wrong with hydractive system, in very abrupt way.
It can happen on change from hard to soft mode, if for some reason the pressure in middle suspension sphere (front or rear) isn't the same as pressure in corner spheres. At that moment, car will very abruptly change its height. I've seen this several times, and only on hydractive Xantias. System is usually switching back to soft mode after harder cornering, braking or accelerating.
When the system is in good condition, this won't happen during the drive. But can happen during pressurising of the system, if suspension wasn't properly depressurised (height lever moved to low before switching the engine off)
Height changes connected with height corrector valves opening can't be very quick.
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