New Accumulator Time??

HST · Post by **HST** » 24 Aug 2005, 23:35

I've just bought a Xantia, & my first Citroen. I wish I'd done it sooner as it is way better than I expected. Being new to the hydraulics I'd just like some comments on how my car is behaving.
It has Hydractive 2. I'm finding the car quite comfortable and the handling/grip excellent, though changes from soft to firm aren't especially obvious when driving. Is the change quite subtle or am I missing something?
I suspect I'm due a new accumulator sphere. Sitting in the boot with the engine on, the suspension dips, then after a short while rises again. Engine off, it doesn't self level. Also, when braking over a relatively long distance, there is slight movement in the brake peddle, coinciding with a momentary slight reduction in braking effort. This doesn't feel like ABS. Firm braking will activate the ABS on a dry road. The regulator clicks at 25 second intervals. Does all this tie in with this sphere needing replaced, or are there other problems?
When moving from maximum height to normal, the front suspension does a little jump before settling at normal. Usual behaviour??
Finally, at max height the LHM level indicator is nowhere near the correct level (it's way above the two lines). At normal height, I've measured the LHM depth at 8cm using a dipstick: is this about right?
Thanks for any help you can give.

Mandrake · Post by **Mandrake** » 25 Aug 2005, 02:23

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by HST

I've just bought a Xantia, & my first Citroen. I wish I'd done it sooner as it is way better than I expected. Being new to the hydraulics I'd just like some comments on how my car is behaving.
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Welcome to the fold. [:D]
<blockquote id="quote">quote:<hr height="1" noshade id="quote">
It has Hydractive 2. I'm finding the car quite comfortable and the handling/grip excellent, though changes from soft to firm aren't especially obvious when driving. Is the change quite subtle or am I missing something?
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No, its not subtle, the ride is quite noticably harsher when it switches into firm mode. If the centre console switch is is in the normal mode (light out) then it doesn't switch to firm mode unless you're cornering rather hard. In sport mode (light on) even moderate corners taken at speed will trigger a switch to firm mode, as will flicking the throttle.
Theres been a couple of long running threads recently about diagnosing the Hydractive 2 system - have a look at those. The most common problem is that a hydractive centre sphere wears out and eventually punctures, leaving you with only the corner spheres for ride, in which case there is no change between soft and firm mode.
As a very quick test to see if it is switching from soft to hard, open the bonnet and drivers window, all other doors and tailgate closed, let the engine run until the height is normal, then do a manual "bounce test" at the front (just press down on the frame between the headlights) and the back (corner of the boot) and the suspension should be quite soft.
Now turn the key off without opening any doors and wait about 30 seconds. You should hear a whining noise which is the solenoids staying on to engage soft mode, and after 30 seconds a click and silence is it switching back to hard mode to conserve battery power.
Now try the bounce test again (note - don't open the tailgate, or any doors) and the suspension should be at least twice as stiff, and also the rebound will be very firm.
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I suspect I'm due a new accumulator sphere. Sitting in the boot with the engine on, the suspension dips, then after a short while rises again. Engine off, it doesn't self level. Also, when braking over a relatively long distance, there is slight movement in the brake peddle, coinciding with a momentary slight reduction in braking effort. This doesn't feel like ABS. Firm braking will activate the ABS on a dry road. The regulator clicks at 25 second intervals. Does all this tie in with this sphere needing replaced, or are there other problems?
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Sounds like an accumulator sphere is needed, yes.
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When moving from maximum height to normal, the front suspension does a little jump before settling at normal. Usual behaviour??
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Usual behaviour ? Not exactly. (EG they didn't design it to do that) Common behaviour ? Yes...mine does that too, and it's something to do with the way the hydractive valve works that means that if the suspension is fully up and allowed to switch into hard mode, when the solenoid switches into soft mode again when you start the engine the hydraulic plunger is not able to move to engage the soft mode, as there is too much counter pressure in the centre sphere.
As the suspension comes down and the regulator pressure increases suddenly the valve opens and the car leaps up with a pop. Disconcerting, but nothing to worry about I think.
You can minimize the chance of it happening by always starting the engine about 10-15 seconds before lowering the height lever and leaving the engine running during the lowering to ensure that maximum regulator pressure is available to switch the hydractive valves. (Which utilize the main pressure supply to push a plunger to perform a hard to soft transition)
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Finally, at max height the LHM level indicator is nowhere near the correct level (it's way above the two lines). At normal height, I've measured the LHM depth at 8cm using a dipstick: is this about right?
Thanks for any help you can give.
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The gauge is an expanded scale gauge, so it only moves within a small range of oil levels. As I pointed out to someone else in another thread, its actually designed to measure the MINIMUM oil level that occurs at the full height position, not the maximum.
You could try siphoning a bit of oil out and see if the gauge drops, if not, put the oil back in. The only consequence of the oil level being too high is the tank overflowing when the suspension is set right down.
Regards,
Simon

HST · Post by **HST** » 25 Aug 2005, 03:48

Thanks for the helpful reply.
I've checked the suspension with the engine on & off and can definitely feel the difference, front and back. Looks like it is working as it should. Maybe I was expecting it to be a bit softer in soft mode. I've never been in a hydropneumatic Citroen, but have been in a few BL Hydragas cars (that ages me!) & thought there might be more of that floaty feel. What I've got seems good to me, so no complaints. Comfort and body control. Bliss.
I've looked at the level of LHM at the two extremes & its not overflowing or empty at either, so I'll not lose any sleep.
Right, must go and order that sphere....

Mandrake · Post by **Mandrake** » 25 Aug 2005, 04:07

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by HST

Thanks for the helpful reply.
I've checked the suspension with the engine on & off and can definitely feel the difference, front and back. Looks like it is working as it should. Maybe I was expecting it to be a bit softer in soft mode. I've never been in a hydropneumatic Citroen, but have been in a few BL Hydragas cars (that ages me!) & thought there might be more of that floaty feel. What I've got seems good to me, so no complaints. Comfort and body control. Bliss.
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Although you've proved its switching modes between hard and soft ok, that doesn't necessarily mean the soft mode is as soft as it should be, if the spheres are getting a bit low on gas it could be harder than it should be, but its not straightforward to diagnose if you're not familiar with how soft the ride SHOULD be, or have a pressure tester.
On the other hand, it seems like modern Citroen's don't have quite the "magic carpet" ride of some of the earlier models. I've driven the GS and CX before and the CX definately has a better ride than my Hydractive 2 Xantia.
I think there are two main reasons - one is the use of McPherson struts at the front in the Xantia vs double wishbone suspension of the CX, GS etc (the McPherson struts are definately a compromise) and also that they're choosing to tune the damping a bit firmer. (A lot of people didn't like that floaty feeling of light damping)
One other thing that can improve the ride quite a bit is greasing the front struts. See my comments about that in this thread:
http://www.andyspares.com/discussionfor ... hichpage=3
Regards,
Simon

HST · Post by **HST** » 25 Aug 2005, 04:39

Yes, it's quite possible it's not as soft as it should be. The fact I'm not feeling that much when driving certainly points to that - I'm not getting much roll at any time. Since there is at least some difference I'm going to hold off swapping hydractive spheres for the moment (though not for too long). A cambelt change is higher up my priorities. It's not due for several thousand miles, but I'm a little paranoid about it snapping just after buying a new car! My last car had a chain, so I was spoilt.

HST · Post by **HST** » 27 Aug 2005, 15:47

I've now changed the accumulator sphere, which took about three minutes. After depressurising, it just screwed off by hand.[:D] I'm glad I didn't take it to a garage.
This has made a big difference. The car now passes the boot sit/engine off test. The regulator is clicking at more than 90 second intervals (I stopped timing at that point) and the brakes feel more normal. The suspension also seems softer, though that may be my imagination!

IanR · Post by **IanR** » 27 Aug 2005, 23:17

[quote]After depressurising, it just screwed off by hand.[:D]/quote]
You sound like a very useful guy to have around. However, I shall be extremely careful not to offend you. [:)]

Mandrake · Post by **Mandrake** » 28 Aug 2005, 06:07

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by HST

I've now changed the accumulator sphere, which took about three minutes. After depressurising, it just screwed off by hand.[:D] I'm glad I didn't take it to a garage.
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You're one of the lucky ones [:)] Sometimes they can be incredibly tight if the previous person overtightened them, or if the faces have rusted together a bit.
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This has made a big difference. The car now passes the boot sit/engine off test. The regulator is clicking at more than 90 second intervals (I stopped timing at that point) and the brakes feel more normal. The suspension also seems softer, though that may be my imagination!
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It's probably not your imagination, and although the regulator sphere itself can't in theory affect the ride quality, I've also noticed that whenever the suspension is depressurized or exercised over its full down, full up range the ride seems to get temporarily better.
My best theory is it is to do with friction in the front suspension struts - after I greased mine a couple of weeks ago the ride immediately improved, but that improvement has reduced a bit since then, but if I work the suspension over its full range again, the ride improves again for a few days.
Seems to me like they don't put enough lubrication in the struts, and could really have done with some kind of grease nipple part way down the strut....
Has anyone ever dissassembled a Xantia strut or have any accurate internal drawings of one ? Or figured out a better way of getting a decent amount of grease well down into the strut other than trying to work it in from the top ?
I'm sure any Xantia more than a few years old suffers from a harsher ride than it should have simply due to lack of strut lubrication...
Regards,
Simon