Poor xantia comfort and ride

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XantiaDaveEire
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Post by XantiaDaveEire »

Old-Guy wrote:
XantiaDaveEire wrote:I meant when manually adjusting the height from inside the car to high and low it can be slow at the rear to adjust heights,the lever is hard to move into the high position ,it takes two hands two pull it all the way up compared to my silver car it will move up with ease..Is there anything i could do to try and free it up ?
You've answered your own question - at least in part. You need to sort out the rear height adjuster mechanism so that the lever moves as easily as in your other car. Personally, I wouldn't start investigating spheres until you've dismantled and thoroughly cleaned up the mechanism.

Final thought: did you thoroughly bleed the brakes when you changed the spheres (you need to pump about ½L through each rear caliper as the rear brakes get their pressure from the rear suspension, to clear out all the old LHM.
I haven't bled the brakes altought it might be worth doing...are the rears more queationable than the fronts?
1998 Xantia 1.9 TD 186k
2008 C4 grand Picasso exclusive 105k #-o
aerodynamica
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My Cars: 2008 C5 Exclusive Tourer
1993 Xantia 1.9 TD VSX Mk1 Sinker A.K.A Slugmobile 13'
'Old Katy'
previous convictions: totaling 52litres of LHM in one go:
1968 ID19B 'Old Polly' Stellar white
1993 Xantia 1.9 TD SX Mk1 Sinker Silver
1992 XM 2.0 SEi Turbo Manual Anthracite Grey
1982 CX 20 Pallas 'Old Goldy'
1993 XM 2.1 SD Auto Light blue
1993 Xantia 1.9 TD SX Mk1 Sinker light Blue
1982 BX 16 TRS 'Cyril' Vallelunga Red
1995 Xantia 1.9 D SX Auto Dark green
1977 CX 2400 Pallas C-Matic 'Aphrodite' Regatta Blue
1982 GSA Pallas SE Silver Pearl
1980 CX 2000 Reflex Vallelunga Red
1978 CX 2400 Pallas C-Matic 'Prometheus' Midnight blue
1984 BX 14E 'Cecil the slugmobile' Maroon
1987 Fiat Panda 'the mighty panda'
x 97

Post by aerodynamica »

55 psi (sic) pressure at the front? that's a BX sphere you have my Son!

I am sure the Xantia should generally have 70(odd) Bar pressure on 400cc-sized spheres with whatever damper is specced for the model in question. The rears are something like 35Bar pressure. I recall this from the Citroën spec. sheet for the spheres for the various Xantia models.

Thing is, even with BX fronts fitted, the difference in ride will not be so severe as to cause these large observations. I think you either have massively over-pressured spheres (like over 70b) or the spheres are new but duff. (or they've given you hydractive corner 'sport' spheres by mistake)
20bar increase is huge, too much pressure and it will ride awfully.
That's true! but it depends on the weight of the car: if they're 20 bar too low, it'll make it a bit 'rubbery' but will still ride well. If it's 20b too high you might get a phenomenon where the suspension seems really soft to press down on but will not allow any 'drop' to the wheels for potholes.
I found this out with my old BX16 TRS; I had new front spheres for it: 55bar, 400cc 1,9 marked damper but just for experimentation, i temporarily fitted my CX fronts to the BX for a trial. These are 75bar, 500cc but the same damper.

The larger sphere volume with the same damper should give a softer FEELING ride as the spring rate-of-change-per-stroke is shallower, but only if the pressure was about the same (55bar), but of course the CX has 75 bar and this turned out to give a horrible, crashy ride. Why is this? It turns out to be due to the fact that 75 bar on a BX, is too close a pressure to the pressure of the LHM holding up the front suspension (guess it's about 80b or something) and as such, when standing static, the sphere is still 'uncompressed' when the car is at normal height; the pressure needed to hold it up is not enough to move the inner sphere diaphragm to its idealised 3/4 position away from the back of the damper. It leaves not enough LHM volume in the sphere for the gas to push the strut down a pot hole: the diaphragm in the sphere was too close to the back of the damper and where a pothole was met, there was a sharp, hard jolt where the LHM went to a spike of negative pressure as the diaphragm whacked the back of the damper. You could replicate it in the garage by bouncing the front - if moved down plushly but to try to lift it up; it kind of 'jammed'.

refitted the lower pressure spheres and all was restored.

If I'd found CX fronts that had lost some pressure down to say 60bar from 75, they'd probably have given a supreme ride as there would be a full house of ideal states: larger (500cc) sphere volume, fairly slack (1,9) damper and a higher than (BX) standard pressure to give more gar volume to play with in static conditions.

Presently I have a pair of CX Turbo fronts on my Xantia 1.9 TD non-hydractive, These have a slightly firmer damper to the standard CX saloon but the same pressure and volume. I had these regassed to 80bar over the normal 75b. a year back and this gave the best ride ever. On the Xantia, the heavier diesel engine allows for the use of the higher pressure spheres and they perform brilliantly. (by good luck the CX Turbo used a similar damper calibration to a standard 1.9TD Xantia) the bigger size of the CX spheres allows for a softer spring over the travel of the suspension compared with the smaller 400cc size standard for a Xantia.

Coupled with the standard rears of the Xantia these CX fronts don't seem mismatched but I'm keen on using slightly higher pressure spheres on the rear too. Say, 40bar instead of the 35 standard. I'm fairly sure this will give a softer spring with sensible overall damping and motion - only the strut piston diameters and trailing arm-to-piston-pushrod leverage ratio would remain an unknown factor, but I bet these are not massively different to the BX and that model used 40b, 400cc and 40b, 500cc on the estate.

I am WAY too interested in spheres and such.... :)
Graeme M
2008 C5 Exclusive Tourer 2.0 HDi
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DickieG
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Post by DickieG »

aerodynamica wrote:55 psi (sic) pressure at the front? that's a BX sphere you have my Son!

I am sure the Xantia should generally have 70(odd) Bar pressure on 400cc-sized spheres with whatever damper is specced for the model in question. The rears are something like 35Bar pressure. I recall this from the Citroën spec. sheet for the spheres for the various Xantia models.
Apologies for the correction Graeme but the 70 Bar sphere's are for 1.8 and 1.9D Xantia's, TD's and 2.0 ones have 55 Bar sphere's at the front, rear pressure is either 30 or 40 Bar. For a full table of sphere's look at this linkthen click on Technics, Technical data then sphere's.
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aerodynamica
Donor 2023
Posts: 1299
Joined: 26 Dec 2007, 18:10
Location: Glasgow
Lexia Available: Yes
My Cars: 2008 C5 Exclusive Tourer
1993 Xantia 1.9 TD VSX Mk1 Sinker A.K.A Slugmobile 13'
'Old Katy'
previous convictions: totaling 52litres of LHM in one go:
1968 ID19B 'Old Polly' Stellar white
1993 Xantia 1.9 TD SX Mk1 Sinker Silver
1992 XM 2.0 SEi Turbo Manual Anthracite Grey
1982 CX 20 Pallas 'Old Goldy'
1993 XM 2.1 SD Auto Light blue
1993 Xantia 1.9 TD SX Mk1 Sinker light Blue
1982 BX 16 TRS 'Cyril' Vallelunga Red
1995 Xantia 1.9 D SX Auto Dark green
1977 CX 2400 Pallas C-Matic 'Aphrodite' Regatta Blue
1982 GSA Pallas SE Silver Pearl
1980 CX 2000 Reflex Vallelunga Red
1978 CX 2400 Pallas C-Matic 'Prometheus' Midnight blue
1984 BX 14E 'Cecil the slugmobile' Maroon
1987 Fiat Panda 'the mighty panda'
x 97

Post by aerodynamica »

Haha Dickie, that explains a few things!

Yep that's the table I was trying to recall.. thanks for the link
Graeme M
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Post by HDI »

This is sounding uncomfortably like it may be the problem with mine :?

Doesn't Plaides have a good rep for spheres though ?
I would have thought out of all the aftermarket suppliers they could be relied upon to supply the correct spheres for a specific model ?
Now using '00 Xantia LX HDI, pov spec :(
My past Citroens :-
'00 Xantia SX HDI, now dead due to accident :(
'99 Xantia HDI 110 Exclusive, RIP :(
'97 Xantia TD SX
'96 Xantia TD LX
'96 ZX TD
'89 BX TD
'88 AX GT
'79 CX2400 Pallas (scrapped :( )
& a couple of Peugeots !
XantiaDaveEire
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Post by XantiaDaveEire »

HDI wrote:This is sounding uncomfortably like it may be the problem with mine :?

Doesn't Plaides have a good rep for spheres though ?
I would have thought out of all the aftermarket suppliers they could be relied upon to supply the correct spheres for a specific model ?
The main problem i'm having with mine is that the rear is slow to adjust heights and uncomfortably hard when driving :roll:

I'm going to take two videos of both my cars and post them on here to see if that might make things easier to diagnose,because i've got spheres off the same company before and they were fine .

I'll try and get a video up as soon as i can

Dave
1998 Xantia 1.9 TD 186k
2008 C4 grand Picasso exclusive 105k #-o
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