XM Hydraulic Issue - Bumpy?

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Chillmaxxx
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XM Hydraulic Issue - Bumpy?

Post by Chillmaxxx »

Hi All

On paper my late model 24v should be riding fine, new spheres & been checked over, but she's not right, the ride's off & lumpy/ bumpy, non floaty. On the way back from the garage yesterday, I don't know why, but I put her in intermediate ride height, & she was jumping about all over the place, so I knew something was officially wrong. I've driven like that before & not even know she was in semi high until I looked down.

Any ideas anyone, I'd love to sort her! Could the new spheres be at fault?

Many thanks Justin

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xantia_v6
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Re: XM Hydraulic Issue - Bumpy?

Post by xantia_v6 »

It is most likely that your suspension is permanently in firm mode and not switching to soft mode. There are several possible reasons for this.

If the problem began when the spheres were changed, then you need to check that the correct spheres have been fitted in the correct locations, particularly the centre spheres. Unfortunately on an XM, access to the centre spheres is not easy, and you will probably need to get the car put up on ramps and have the spheres removed again to check the part numbers.

If the problem is not with the centre spheres, it is most likely an electrical issue in the hydractive control system. The most common failures are the diodes contained in the hydractive solenoids. These can be supplemented with external diodes to fix that issue (search this site for "diode modification" or "crofting" for more information).

It is also possible that there is a different electrical failure, but you may need someone with experience in diagnosing the hydractive 2 system to pinpoint the problem.

Raatokalle
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Re: XM Hydraulic Issue - Bumpy?

Post by Raatokalle »

"On the way back from the garage yesterday"
Did bumpy ride started happening after changing spheres? Does suspension get stiff all the sudden if you happen to drive, example to road bump? Does car front end bounce back up, when you put ride heigh way up and then lower it way down?
I'd suspect there is air in the system. Especially if you changed spheres and didn't bleed the system all the way, aka jump car up and down/steer the wheel from left to right and etc etc.

Mine does the same, altho for most of the time ride is perfect. Until i happen to drive to a road bump way too fast, car's front end becomes rock solid for a second or two until "tenstion is released" and suspension starts to work again. Also front end bounces back up for a second when i drop heigh down to low from high. Im pretty sure i have "air leak" somewhere which i haven't located yet. If i have understood correctly, if some return pipes/hoses to hydraulic pump have even slightest wear and tear, it may cause that.

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xantia_v6
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Re: XM Hydraulic Issue - Bumpy?

Post by xantia_v6 »

Raatokalle wrote:
22 Apr 2019, 20:38

Mine does the same, altho for most of the time ride is perfect. Until i happen to drive to a road bump way too fast, car's front end becomes rock solid for a second or two until "tenstion is released" and suspension starts to work again. Also front end bounces back up for a second when i drop heigh down to low from high.


Your symptoms sound more like an electro valve bias spring issue (see viewtopic.php?t=31881) or system pressure issue, for which Citroen eventually introduced improved hydractive blocks (although they only officially recommended them for the Xantia). See viewtopic.php?p=494381#p494381

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white exec
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Re: XM Hydraulic Issue - Bumpy?

Post by white exec »

Hi Justin,

All good advice above.

- Check that the correct spheres were fitted, and to all positions, including the centre ones
- Check that system was bled at the brake calipers, using the correct procedure
- Check that the front and rear electrovalves are operating as they should

How was the suspension before the sphere replacement?
Is the garage familiar with Hydractive suspension?

On XM, putting the height to Intermediate High can produce a firm ride; soft may well not available there, but should be on Normal, so that in itself is not unusual.

If you can post the car's VIN (which will be masked), we can be sure of its full factory spec.