rear suspension sinks (C5)

ed1 · Post by **ed1** » 09 May 2010, 08:41

hi folks.
Rear sinks right down when parked for a while on my c5. Garage says its both rear spheres. Car is jus over 3 years, just out of warranty and only done 41000 miles???
Many other experts say its anti sink valves but citroen parts dept say c5 doesnnt have anti sink valves?
Can anybody help me in this dilemma as i dont want to part with 350 quid for spheres if that's not the problem?

Post by **myglaren** » 09 May 2010, 10:11

Unlikely to be the spheres.
There is an anti sink valve in the C5 inasmuch as it is a valve that opens to allow the height to be adjusted then closes to stop the return of fluid to the reservoir. Under the control of the height correctors.

The valves should be locked shut when the car is locked so the car shouldn't sink perceptibly over several days. If the valve is not closing properly or has developed a leak then the car will sink.

If you have a look at some of the C5 threads you'll find a couple of examples, one fairly recently.

If the spheres were ruptured the ride would be very uncomfortable and once filled with fluid wouldn't sink anymore.

Considering the layout of the C5 hydraulics, where the fluid is in a comparatively closed system, unlike the previous systems, I have a hard time imagining that the spheres could be responsible.

citronut · Post by **citronut** » 09 May 2010, 10:34

that sounds an aufull lot of dosh for two spheres,

regards malcolm

Post by **myglaren** » 09 May 2010, 14:07

citronut wrote:that sounds an aufull lot of dosh for two spheres,

regards malcolm

It is indeed Malcolm, C5 spheres are a bit more expensive than previous models but not that much - I believe thay are about $45~50 each although may be mistaken with that, it shouldn't cost that much to replace all the spheres on the car.

AEP list them at £45 inc. VAT.

ETA:

AEP
Easy Installation

This Suspension Sphere can usually be fitted very rapidly at home. However if you are not comfortable installing this suspension sphere yourself you can take it to your closest MOT, service or Citroen garage who will be able to fit it for you for an extra fee.
Typical Savings:
Self Installation: Save £100 (69% less)
Garage Installation: Save £50 (53% less)

Citroenmad · Post by **Citroenmad** » 09 May 2010, 14:25

Is it an estate or hatchback?

I asume the estate has something else to control the height of the rear seperate to the front, as its rear height can be changed with the button in the boot without effecting the height of the front. Might it be something to do with this if it is an estate.

If not it could be the anti sink valve, however im not sure how these work on the C5s, i asume its just an electronic valve somewhere.

When you unlock the car does the car pump back up to normal height?

Thats a huge bill for a pair of spheres, and it wont be the spheres causing the sinking at the rear. I very much doubt it.

I think genuine Citroen spheres for C5 are around £80 each?

Post by **myglaren** » 09 May 2010, 14:42

I presume that on the estate the manual height selector in the boot overrides the rear suspension height settings temorarily.

As soon as the tailgate is closed normal service is resumed and the car re-attains it's standard ride height.

The button only works with the engine off and the tailgate open.

ed1 · Post by **ed1** » 09 May 2010, 17:55

Firstly - thanks to everybody thats responded!
It's a saloon and it was a citroen dealer that quoted £350. To put you in the picture, when I noticed the rear sinking (takes at least an hour or two to sink) I contacted citroen uk via email and explained the car was just out of warranty. However, I argued that, as a non-service item that should last up to 200000miles without any maintenance they should consider a goodwill gesture. They suggested I take it to the dealer I bought it from to have it inspected but asked if I had it servcied regularly at a citroen dealer - that's where I came unstuck as the final service in January was not done at a citroen garage. Reason - where I originally bought the car was within good driving distance and I had been buying citroens there for over 10 years but it was taken over and subsequently closed down - the next nearest verve dealer was about 30 miles away so I defected to a closer garage. As it was serviced at non-citroen dealer they would not consider a goodwill gesture. I did go to verve over 30 miles away for inspection at their suggestion and was promised a report would be sent to cit uk. paid for inspection and was fiven a quote for £350 for both spheres.
I agree it is unlikely for one sphere to go at such low mileage but BOTH!!!???
Anyway, my dilemma continues - where is the anti sink valves on the C5? There is a block with the pipes from spheres connected, attached to the rear axle and near to the electronic height detector switch (I think anyway. This block has 3 pipes attached - from what I've researched so far the anti sink thing has 5 pipes? Incidentally, the citroen dealer parts person said the anti sink is controlled electronically through the suspension ECU??
I am very confused and really very hacked off with citroen.
Cheers - keep the responses coming and many thanks again.
Eddie

Post by **myglaren** » 09 May 2010, 19:13

He is correct that the anti-sink is electronicaly controlled through the ECU, the same valves that self-level the car when driving and deremine the other selectable heights. When they are closed off, it is by default anti-sink and they close when the doors are locked (and the engine off, of course)

IIRC on of our members had problems with the rear valves and had similar symptoms to your own. He replaced the rear valve and discovered that either it had been replaced at some point prior to him purchasing the car and installed the wrong way round. Either that or the rear height corrector potentiometer was fitted in reverse, memory is a bit hazy on that. Need to check that thread for accuracy.

ed1 · Post by **ed1** » 09 May 2010, 19:55

Thanks for that.
Starting to feel like I'm getting somewhere now. How easy is it to replace the valve (presumably the thing with 3 pipes going into it) and / or the potentiometer? What about bleeding the system after disconnecting pipes etc - I'm ok with bleeding brakes but never tackled this before.
Incidentally, the ESP/ASR orange triangle light now comes on and the display indicates this system is faulty. Car still goes well and handles great but........
I have a code scanner but no fault codes show.
Cheers
Eddie

Post by **myglaren** » 09 May 2010, 19:59

You will need a Lexia to interrogate the suspension system ECU properly.

ed1 · Post by **ed1** » 10 May 2010, 11:42

Thanks.
Help - is there any member near west lothian with a lexia??

Eddie

cachaciero · Post by **cachaciero** » 10 May 2010, 15:51

O.K! O.K! Lets have a little logic here.

First there are no valves as such that you can change on any C5 unless you are going to rip the BHI apart.

What model are we talking about here the reference to a valve with three pipes going into it sounds like it may be refering to a center sphere on an H3+ car.

I can't envisage any failure of the center sphere assy causing the rear suspension to drop.

Have you checked for leakage around the struts? are the gaiters full of oil? strut failure does not appear to be that uncommon, documented failure of the valves in the BHI less so.

Once the car is switched off and locked up any sinking can only be due to leakage, either through the electrovalves in the BHI or around the strut (s) the height correctors being electronic devices are only active when the BHI is powered up. Normally I would say get a Lexia on it but in this case given that the system appears to be working correctly I don't think the Lexia will tell you anything you don't know, in fact it probably won't even tell you what you do know i.e you have a slow leak somewhere.

EDIT The thing with three pipes going into could be the distribution block on an H3 car the only other thing on this iirc is the bleed screw.

cachaciero

ed1 · Post by **ed1** » 10 May 2010, 16:29

Thanks Cachaciero.
The model is 2 litre HDI (138 HP) VTR. There is no centre sphere and your suggestion of distribution block with bleed screw is spot on. When unlocked the suspension pump starts and the rear rises to normal height after about nearly a minute. It goes to all heights as it should and maintains pressure even when towing a horse trailer. Still handles good etc etc. It's just this sinking and the esp/aer warning light coming on now that's bugging me. Incidentally, first signs of sinking was nearly couple of months ago and esp light just came on last week - don't know if both faults are in some complex roundabout way connected?
Just received an email today (eventually) from citroen uk customer services manager stating that he has looked at my case and won't be considering a goodwill gesture! No great surprises ther then.

cachaciero · Post by **cachaciero** » 10 May 2010, 20:33

I feel it very unlikely that a problem with the ESP/ASR system is related to the suspension problem. However in this case I would say that you need to get it on a Lexia sooner rather than later.

The ESP/ASR system is a very complicated system with lots of data links to most all the other ECU's on the car, couple this with a whole range of sensors and it becomes clear that there are lots of potential reasons why the system is failing.

cachaciero

ed1 · Post by **ed1** » 11 May 2010, 21:24

Thanks Cachaciero.
Unfortunately I don't have a lexia and can't really afford one. Is there anyone reading this in the Lothians/Fife/Lanarkshire/Stirlingshire areas that ahs one they can hire / rent?