Xantia rear height regulator calibration

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skog77
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Xantia rear height regulator calibration

Post by skog77 »

Hello there, i recently bought a Xantia with a seized rear height regulator (common problem here in Norway due to salt on winter roads).

I've checked it out, and what usually happens is that the small plastic arm pops off due to the thing being seized up. However, here it's actually the tiny metal rod that connects the plastic arm to the clamp that sits around the big bar.

So i'm assuming i might have to replace the clamp as well. However this means that the new clamp has to be fitted precicely how the old one was, as it opens and closes the valve with milimeter presision. If i'm off the valve won't open and close. This pantent seems daft to me, unless i've missed something essential.

Any idea on how to calibrate this? It's pretty difficult to do it by eye.
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Post by CitroJim »

Hi skog77 and welcome to the forum :D

yes, the clamp will need replacing and indeed the resetting of the ride height is a critical and time-consuming job.

Mark the present position of the old clamp on the anti-roll bar and install the new one in the same position. It will then not be far out.

You will need to dismantle and free off the height corrector mechanism as it will be stiff, if not well seized up and will have led to the clamp breaking. Also replace the white clip as they can suffer hair-line cracks in their ball cups and it'll just keep popping off.

The only way to reset the ride height is on a ramp. Slightly adjust the clamp until the ride height settles out correctly. It is fiddly, time consuming (as you must exercise and bounce the suspension each time to ensure the height settles correctly) and just small movements of the clamp cause very big corresponding changes in height.

The job must be done on a ramp as the car must be level and with weight on all four wheels. Also, because of the danger of sudden height drops whilst adjusting, you must work such that there is no possibility of the suspension suddenly dropping and crushing you. These cars can KILL. Take great care!

Let us know how it goes :wink:
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Post by skog77 »

Thanks for the quick reply CitroJim!

I was hoping there might have been some bulletproof way of calibrating it, how do i know when it's in perfect ride height?

And i guess after taking it for a spin it might have settled and be in need of more adjustment?


Btw a follow-up question as i'm trying to figure out exactly how this works, i've never owned a Citroen before:

I've actually managed to free up the mechanism, and make it go up and down while on the ramp by manually manipulating it (i will still replace it as it is worn out and very rusty). But I thought i'd be able to set it to mid-ish height and drive it even without the link connected to the bar, as the car has an anti-sink sphere. I just expected it to be less firm and maybe bouncing more as there would be no valve action to up the pressure when needed.

But to my surprise the car sunk all the way down at the back until i eventually blinded every oncoming car and the ride was hard again.

Does this mean that the valve is broken, or is it actually supposed to be open during normal driving? If so i guess that means that the action of the mechanism is to close the valve when the rear end moves down.

Thanks for the reply! Seems like there is a lot of knowledgeable Citroen people out there.
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Post by CitroJim »

skog77 wrote:And i guess after taking it for a spin it might have settled and be in need of more adjustment?
Very possibly! This is why when adjusting the ride height it is a good idea to exercise the suspension between adjustmensts by sitting in the tailgate to make it go down and then rise again to ensure it returns to the correct height. As you get off the tailgate, the car should rise and then fall back to the correct height.

Height corrections do not happen instantly; they take around 20-30 seconds as the height corrector has a deliberate hysteresis to prevent rapid height corrections when travelling bumpy roads and so on.

It is very difficult to "set" a fixed ride height and what you have experienced with it sinking right down is typical. If the white link is broken or disconnected, the suspension either goes to maximum or sinks to minimum, even on the lever a nice mid-point cannot be set and even if you could, the ride would be bad. The movement of the height corrector, even if not actually correcting height, is essentail to the good working of the suspension. I believe because if the height corrector is static, hydraulic fluid cannot flow at all to and from the suspension cylinders. In short, the link must be in place for everything to work properly.

The sphere at the rear that is called the "Anti Sink" is mis-named. It is in fact an accumulator for the rear brakes and has noting whatever to do with anti-sink!!!

A quick check on correct ride height at the rear is to observe the top of the tyre in the wheel arch. There should be just a tiny gap visible, just about a little fingers width.

For a good read on Citroen hydraulics in general, have a look at theCitroen Technical Guide. It is a big PDF document and very, very good. It tells in very good but easily understood language how it all works.

Youo'll find plenty of Xantia knowledhge on this forum! Most problems have been well covered and a search should give the answers but if you cannot find what you need, do please ask! I hope you enjoy your visits here :D
Last edited by CitroJim on 29 Dec 2009, 09:06, edited 1 time in total.
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Post by DickieG »

skog77 wrote:I was hoping there might have been some bulletproof way of calibrating it, how do i know when it's in perfect ride height?
What you can do is to set it "by eye" which will be close enough, if you use this picture as a point of reference you won't be far out.

Image

skog77 wrote:I've actually managed to free up the mechanism, and make it go up and down while on the ramp by manually manipulating it (i will still replace it as it is worn out and very rusty). But I thought i'd be able to set it to mid-ish height and drive it even without the link connected to the bar, as the car has an anti-sink sphere.
What you could do as a very temporary measure is to set the height manually by getting under the car and moving the height corrector until the height is "set" at roughly the correct height according to the load the car is going to carry, i.e. when setting it make sure that you have the same number of passengers/luggage on board for when you will be driving the car.

The anti-sink sphere won't have any effect on ride height if the plastic link or roll bar clamp are not connected.
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Post by skog77 »

CitroJim wrote:If the white link is broken or disconnected, the suspension either goes to maximum or sinks to minimum, even on the lever a nice mid-point cannot be set and even if you could, the ride would be bad. The movement of the height corrector, even if not actually correcting height, is essentail to the good working of the suspension. I believe because if the height corrector is static, hydraulic fluid cannot flow at all to and from the suspension cylinders.
Yes, but this is what strikes me as strange. If hydraulic fluid does not flow anywhere, the suspension should not lower itself?
DickieG wrote:What you could do as a very temporary measure is to set the height manually by getting under the car and moving the height corrector until the height is "set" at roughly the correct height according to the load the car is going to carry, i.e. when setting it make sure that you have the same number of passengers/luggage on board for when you will be driving the car.
Yes that's what i thought i could do. I went for a ride to make it settle, raised it again but even so it dropped down to a minimum after only 2 kms.


I guess this is all academic, as i will replace everything anyway, i'm just trying to figure out why it would drop like that. My only guess is that the valve is in slightly open position allowing fluid to flow away.
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Post by addo »

Would this help? 185/65/15 tyres @ 36PSI, engine running and warm, car lowered to bottom then raised and allowed to sit/stabilise.

Image

Aussie cars don't rust; this was photographed at about 120K (km) and has never been dismantled for repair. So, you can be quite sure it's how the factory set them.
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Post by skog77 »

addo wrote:Would this help? 185/65/15 tyres @ 36PSI, engine running and warm, car lowered to bottom then raised and allowed to sit/stabilise.
Excellent, thanks Addo!
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Post by DickieG »

DickieG wrote:What you could do as a very temporary measure is to set the height manually by getting under the car and moving the height corrector until the height is "set" at roughly the correct height according to the load the car is going to carry, i.e. when setting it make sure that you have the same number of passengers/luggage on board for when you will be driving the car.
When I say "very temporary" I mean just that as in sufficient to get you out of a problem such as being immobile so that you could get the car home or get to a dealer to buy parts etc. Without the anti roll bar link in place the car will eventually sink due to the (designed) by-pass of fluid within the suspension cylinders.
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Post by CitroJim »

DickieG wrote:Without the anti roll bar link in place the car will eventually sink due to the (designed) by-pass of fluid within the suspension cylinders.
Thanks Richard :D That was what I was trying to say...
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Post by Old-Guy »

Hi Skog

I agree with all the advice so far. You may find the following PDF documents on my website (link in signature) helpful: -

'Height Adjuster Units'
Includes line drawings of the mechanisms

'Ride heights and wheel alignment'
Gives the critical measurements and shows where they are to be taken from.

I would repeat the advice about making sure that when the car suddenly sinks you wont be crushed. And, as Jim says, every time you make an adjustment or move the suspension, you have to wait 20 seconds or so for it to settle.

I don't wish to insult your intelligence, BUT obviously the suspension is only 'active' when engine is running and being self-levelling, the load in the car doesn't make any difference to the ride height. In practice, a good load in the back makes the suspension response rather more positively.

Best of luck

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Post by skog77 »

Thank you everyone, i didn't realize there was a bypass, but now it all makes sense! The system is more intricate than i thought. :)

Tomorrow i'm popping across the border to Sweden to pick up the parts. Dealerships in Norway are charging almost 300 pounds, but in Sweden it's about half price.

Old Guy, that's a great page i'll be sure to bookmark it. All cars have their little quirks, but it seems like Citroen owners are very good at documenting solutions :)
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Post by citronut »

300 pounds!!!!!!!!!!!!!!!!!

over here the metal clamp/link is about 12 UK pounds and the nylon lonk is a pound or two,

what are you getting for that 300

regards malcolm
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Post by skog77 »

citronut wrote:300 pounds!!!!!!!!!!!!!!!!!
over here the metal clamp/link is about 12 UK pounds and the nylon lonk is a pound or two,
what are you getting for that 300
regards malcolm
No that's for the entire thing. Valve, mechanism and the link unit.
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Post by Deanxm »

Hi Gents

The easiest way ive found of setting the ride height is to have all the linkages attached, cleaned and well lubed then undo the clamp on the arb, now push/pull the slide valve of the height corrector in or out by hand to get the correct height between the bottom of the subframe and the floor (if thats were its measured from on the xantia's) and when you have the right height pull the car down and let go then measure, push up then let go and measure again, the specified height should be an average of the two you have just taken, when all done just carefully pull the car to the specified ride height again then do the clamp back up on the arb and bobs your uncle.

5 minute job once its up on ramps, trying to adjust the height by turning the clamp on the arb, tightening it then checking will take ages!.


Good luck
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