C5 Suspension Problem Poor Ride Quality

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NigMos
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C5 Suspension Problem Poor Ride Quality

Post by NigMos »

Hi All
I posted a query a couple of months ago about ride quality. To recap, my C5's ride had been gradually getting worse over about six months becoming very harsh and loosing that soft edge. As its under warranty I got it back to the dealer and they changed the COM2000 unit. It was ok for a couple of days then became harsh again. Back again to the dealer and they changed the BHI. It has since been better but still has periods when the ride deteriates. I raise and lower the suspension regularly (Citrobics) which sometimes seems to help. There are a couple of specific things I would appreciate any expert comments on.

1/ Sometimes when stationary ie at traffic lights it will suddenly drop a noticeable amount. Could it be a sticking height sensor ?

2/ I have noticed that the reservoir is pressurised. I know it has to be pressurised when bleeding the system but I have also noticed an improved ride with the pressure released.

Sorry this post is a bit long but I would appriciate any comments or similar experiences with ride quality. Thanks

C5 late 2005 HDi Exc Hyd 3
SimonM
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Post by SimonM »

1: Mine does exactly the same thing. The suspension detects how rough the road is, if you are travelling under a certain speed it will raise the ride height, once the road evens out, speed is increased or you come to a stop the car drops to normal height, depending on the way your front wheels are facing this can be quite noticeable.

2: Could you clarify this question please? The suspension is always under pressure during normal use, the only time it is not pressurised is when the suspension is set at it's lowest point.

My car has always had a harsh ride, oddly enough though when it is full of stuff it is very smooth. They don't like "jiggly" roads, it is though the suspension can't cope with rapid movements.
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mooseshaver
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Post by mooseshaver »

When I undo the cap on the the resoivire I ahve to leave it for a while after I have lowered it as the pressure is too high to let me turn it.
Once I do I always get a hiss and there is a warning in the manual telling you its pressurised and not to undo it.

I think mine suffers from poor ride quality, but if I have a go in a Passat or Vectre, I find out what a harsh ride really is, and appreciate my car more. But I still have nagging doubts the ride had dimminshed. Mine is almost 6 years old. I had the suspension serviced at 5 Years, no difference. Perhaps they need those sphere things Xantia owners are always changing. :D

Mine also changes the ride height when stopped. I think a search on here will tell you what makes it do it, I think ride height is checked every 10 seconds, or when you open a door and altered, but you cannot alter the height on a C5 with the foot brake on, so perhaps once you have stopped and remove your foot, its just making the changes its been wanting to make before you put your foot on it?
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NigMos
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Post by NigMos »

Thanks for the replies. Sounds like the positive air pressure in the reservoir is correct and probably nothing to do it. Regarding the general ride quality it has been great for the last few days, then this morning while sat at the lights it dropped and the ride was poor again. I agree it must be something to do with the height control but my normal weekday driving is on smooth roads well below 70 so why does it change. Any further comments / experiences / magic spells appreciated.
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Post by bencowell »

My C5 ride quality is getting worse. The car used to be great in normal mode, tough in 24mph mode and rock solid in 6mph mode. Now it is just as soft in 24mph mode.

The car is softest of all when it is moving from 24mph height to normal height while accelerating.

That makes me think the car is riding too low.

Also, the independent Citroen man found that the front suspension was slow to rise and fall but the rear is fine.
Currently driving a 2004 C5 VTR (old shape) and an Electric Kia Soul. Sorry but the electric one is my favourite!
Formerly Hyundai Genesis 3.8 V6, 2 x Kia Optima, 2 x C5, Xsara and Saxo.
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mooseshaver
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Post by mooseshaver »

bencowell wrote:
Also, the independent Citroen man found that the front suspension was slow to rise and fall but the rear is fine.
My rear suspension is definatly getting slow to rise. Its about to hit six years old so rahter dreading whats going to fail soon.
C5 III Tourer 2.0 HDi 163 Auto Exclusive
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C5 2.2 HDi Exclusive Estate auto 57. Awesome car. Sadly Could not be fixed by Citroen.
C5 1.6 HDi VTR Estate 56. Traded in.
C5 2.2 HDi SX Estate 02. Drowned in the floods of 09.
C3 1.4 HDi 92 SX 52.
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Post by bencowell »

Do you think changing the fluid would help? Does the C5 have filters in the way the Xantia etc did?
Currently driving a 2004 C5 VTR (old shape) and an Electric Kia Soul. Sorry but the electric one is my favourite!
Formerly Hyundai Genesis 3.8 V6, 2 x Kia Optima, 2 x C5, Xsara and Saxo.
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mooseshaver
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Post by mooseshaver »

bencowell wrote:Do you think changing the fluid would help? Does the C5 have filters in the way the Xantia etc did?
I had mine serviced a five years, which was fluid replacment, the garage had never done one before as most people dont bother. I wasn't charged for any filters
C5 III Tourer 2.0 HDi 163 Auto Exclusive
Gone cars.
C5 2.2 HDi Exclusive Estate auto 57. Awesome car. Sadly Could not be fixed by Citroen.
C5 1.6 HDi VTR Estate 56. Traded in.
C5 2.2 HDi SX Estate 02. Drowned in the floods of 09.
C3 1.4 HDi 92 SX 52.
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ncoll
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Post by ncoll »

Hi,
Do you think that the pressure found in the reservoir could nitrogen from a leaky sphere? Maybe the clue to the harsh ride.
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AndersDK
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Post by AndersDK »

ncoll wrote:Hi,
Do you think that the pressure found in the reservoir could nitrogen from a leaky sphere? Maybe the clue to the harsh ride.
This can be diagnosed by trying the Citaerobics. If that cures the problem for quite a while, then its likely to be a leaking sphere.
Note that the term "leaking" has to be interpreted as a very longterm small leak, which still may leave the sphere operable for a long time.

Its the air (or gas) in the hydraulics oil side of the suspension that is the problem. This will cause the same effect as when you slap your hand against a water surface : a rather harsh transition from one element to the other.
Anders (DK) - '90 BX16Image
NigMos
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Post by NigMos »

I have tried citaerobics but in my case it does not help. I am still wondering about the air pressure in the reservoir. The last couple of days I have left the cap slightly loose so it cannot pressurise and it has improved a lot. But it may just be a coincidence. In the Citroen workshop info it talks about pressurising the reservoir to 0.5 bar before bleeding the system. I have also noticed the reservoir cap has a one way valve which lets air in but not out. Am I barking up the wrong tree or could this pressure affect the ride. Does anyone know if the positive air pressure is critical what does it do.
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Post by mooseshaver »

bencowell wrote: Also, the independent Citroen man found that the front suspension was slow to rise and fall but the rear is fine.
My slow rising rear has been solved by new suspension Cylinders. It failed its MOT as they were leaking, but it wasn't noticed in the service beforehand. Its been doing it for a long time now, and its been through one other MOT and service and noone notice, so perhaps they leak slowly to begin with so people don't notice fluid?
I have topped up the fluid sometimes, and I did wonder where it went since it was supposed to be a sealed system, but I don't understand these things and though it was me being wrong
C5 III Tourer 2.0 HDi 163 Auto Exclusive
Gone cars.
C5 2.2 HDi Exclusive Estate auto 57. Awesome car. Sadly Could not be fixed by Citroen.
C5 1.6 HDi VTR Estate 56. Traded in.
C5 2.2 HDi SX Estate 02. Drowned in the floods of 09.
C3 1.4 HDi 92 SX 52.
Saxo 1.1 East Coast.
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