Citroen C5 Mk II Suspension Will not rise

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howardaskew
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Re: Citroen C5 Mk II Suspension Will not rise

Post by howardaskew »

Gibbo,

I doubt that the cap on the reservoir is vented as it usually has some pressure behind it when you open the cap.
I fully agree that the pump is gravity fed. As long as the pump is primed it will work.

My post may imply that the car elevated in just 2 or 3 applications of the Lexia. However it rose only 3-5 points each time I checked and lost count of how many times I had to do this.

I lowered the car back to 115 points and started the process again. To be honest I just want rid of this car!

Many thanks again.

Howard

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Chris,

Looking at the forum there are not many good posts on the suspension pump, many of the posts centre on the cap and how to pressurise it. There are a few slightly heath robinson suggestions for adding a tyre valve to the cap when a simple Eazibleed system (like shown in the Haynes Manual) will do the trick.

There are many good posters with a lot of patience and experience who help here.

I have tried to post photos and add to the knowledge pool in a small way. The Lexia 3 proved invaluable.

Being able to read the sensors in real time proves that they work and also gives the set points as they are adjusted.

Without the Lexia 3 I doubt I would have succeeded here.

Many thanks to all and hope everyone enjoys Easter :)

Howard
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Re: Citroen C5 Mk II Suspension Will not rise

Post by lexi »

The best Heath Robinson of all with the cap pressure I have heard of, is this:
Put a bit of polythene over the tank with the cap removed,
Put a small pin hole in the centre. Put your mouth over it and blow. That works for one guy regularly.
You could plug Lexia in while doing it and check your cardiovascular condition to boot :lol:
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daviemck2006
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Re: Citroen C5 Mk II Suspension Will not rise

Post by daviemck2006 »

^^^^[emoji106]^^^^
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Stickyfinger
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Re: Citroen C5 Mk II Suspension Will not rise

Post by Stickyfinger »

THANK God PSA do not make Defibrillators, they would swap the live and positive on it's wiring and hide the "Fire" button deep inside a FranGilish control menu.
howardaskew
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Re: Citroen C5 Mk II Suspension Will not rise

Post by howardaskew »

Disappointing Update.

The front of the car was on axle stands whilst working on it.

Once the car had the axle stands removed it fell to 67 which is a bit too low.

I lowered the car rear and raised it but the front wont move very far.

This pump is definitely a bit too weak (sounds sluggish) and maybe there is air in the system.

Looking at the pump there are two metal mechanical pipe connections and the third gravity feed.

The fact that the car has risen to 160 at the rear tells me that the pump is primed.

There are two circuits and maybe the front circuit is not operating properly.

I will continue to raise the front and rear on the Lexia until the rear reaches maximum height and then maybe the front will rise?

Under actuator tests there is the front Actuator and rear actuator which also runs the pump.

At the very bottom of the actuator test menu there is a Electric Pump test which when utilitised raises the front actuator also.

I will keep trying all three or else I will not get my drive back!

Many thanks for all suggestions.

As a footnote is it possible to modify the car so that an emergency electric pump could be attached to the car to raise it and get it home to repair?

I remember the EA has portable electric pumps to raise flood barriers that also use hydraulic pumps both diesel pump and mains driven pump versions.

The idea is that should the pump house be destroyed by fire or explosion when the barriers are deployed the portable units allow raising to keep the shipping channels open.

The Tilbury Docks Flood Barrier uses a very complex heath robinson electric pump system with generator back up system.
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Re: Citroen C5 Mk II Suspension Will not rise

Post by howardaskew »

I have my drive back!

Persistence with the Lexia eventually rose the front up too.

The car drove OK but gave the 55mph speed limit suspension fault warning.

The brakes were horrible!

But it has gone away now and will only be back when a suitable unit is available.

The car looked at the correct level and drove nicely apart from the brakes.

I think the suspension pump is definitely a weak point.
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Stickyfinger
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Re: Citroen C5 Mk II Suspension Will not rise

Post by Stickyfinger »

sounds like it is a bleed problem rather than a pump problem to me
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Re: Citroen C5 Mk II Suspension Will not rise

Post by howardaskew »

Stickyfinger,

I think that is a possibility. However after filling the car up with 3.5 litres of LDS I managed to reduce the level so I could comfortably fit another litre in the reservoir.

As the system holds 4.7-5.4 litres this does not leave much room for air.

As the car is used normally and left standing I think the air could find its way out of the system and the performance could improve.

What makes me think that this is a pump problem is the lack of shrill chatter from the pump operation and the dimming of the interior light whilst the pump is running.

Just maybe a better a pump would push everything (including any air) out of the way.

I will keep the forum updated when I have some news.
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Stickyfinger
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Re: Citroen C5 Mk II Suspension Will not rise

Post by Stickyfinger »

C5's pumps do not make much noise and the brakes are on the "end of the line".
My suggestion would be bleed the brakes in the correct order.
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myglaren
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Re: Citroen C5 Mk II Suspension Will not rise

Post by myglaren »

Stickyfinger wrote:C5's pumps do not make much noise and the brakes are on the "end of the line".
My suggestion would be bleed the brakes in the correct order.
Brakes on the C5 are a completely separate system Alastair.
Suspension and steering share the reservoir but have separate pumps.
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Re: Citroen C5 Mk II Suspension Will not rise

Post by Stickyfinger »

sorry thinking Xantia and the op did talk about brakes being bad.
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Re: Citroen C5 Mk II Suspension Will not rise

Post by cachaciero »

Points arising.
Rough running pump. Looking at the photo's in one of them it does look like some of the commutator segments are "blued" on the ends, which suggests a lot of heat so I think that it is possible that some of the armature maybe open circuit or high resistance. I certainly know from my "go around" with the pump that the motor will still spin and pump with brush problems and the odd winding "missing" on the armature.
Pump motors seem to be the same on all models however the firmware in the BHI does appear to have minor differences when I changed mine for one purchased from a scrapper I found that while the suspension stuff worked fine it didn’t appear to provide the correction signals for the Xenon headlights. I ended up using the "new" pump and the original electronics.


Reservoir cap.
Seems to be "one way" i.e out. What the logic is is still unclear to me at least, the following is just my thoughts and should not be taken as a definitive " this is the way it is".

The hiss that you hear when undoing the cap everybody assumes is air hissing out, however could just as easily be air hissing in, I've never been able to work out a viable way of proving it one way or the other :-). However my belief is that when the system was designed it was designed as a sealed for life system and in order to achieve that, particularly if the original oil was envisaged as LHM (speculation) then the exclusion of air or more pertinently water would / should have been a major consideration.
As those of us who have had traditional Cits know, LHM over time (several years!) does sludge and as with all mineral oils water is a major contributor to this process so preventing humid air sitting on top of the oil would / should have been a design consideration to reduce sludging and resulting filter blockage.
The introduction of LDS an oil which is identical in specification to LHM with the one important difference that it is a synthetic based oil and not mineral based would have made this particular design requirement even easier to achieve as it is my understanding that synthetic based oils are generally less hygroscopic than mineral based oils so the use of LDS in a sealed system would in theory anyway allow a closed system to work for many years without the need to drain and clean the hydraulic system, and the filter which is in the pump would outlast the pump.


I don't think that it is a good idea to draw parallels between the older LHM based systems and those on the C5 / C6. The older cars were not designed as a maintenance free sealed for life system and the hydraulics had to look after everything, brakes (heavy thermal cycles) and DIRAVI steering ( high flow and pressure) as well as suspension.(low flow high pressure). On the C5 and C6 the hydraulic system only does the suspension (low duty cycle) the power steering uses a separate pump.

On the older cars the height correctors were mechanical valves with a pressure and return line, further the pipe run from the height corrector to the strut was relatively short and of small diameter steel so in terms of getting air out of the system a couple of cycles of Citrorobics would be able to move air laden oil back to the return line on the height corrector.
However on the C5 the equivalent mechanical part of the height corrector is at the front of the car with in the case of the rear suspension a long pipe run of relatively large diameter rubber pipe to the suspension cylinders so it seems to me that it is quite possible that cycling the suspension may do nothing more than move bubbles of air up and down the pipe.
However it does occur to me that a partial vacuum in the reservoir would help de-aireate the system and I can't help reflecting on the fact that there are bleed valves built in close to the suspension units, I am sure that the designers put them there because they knew they were needed.
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white exec
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Re: Citroen C5 Mk II Suspension Will not rise

Post by white exec »

Helpful thoughts.
For earlier LHM systems, including Hydractive and Hydractive II, there are fairly comprehensive pages in Citroen technical and service documents, which explain the workings of each part of the system, particularly revisions and redesigns. Do we not have this for the LDS-based systems?
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Re: Citroen C5 Mk II Suspension Will not rise

Post by cachaciero »

I am sure if you can get access to Citroen documentation the answer is yes. Certainly I have some Citroen Training Documentation for the Earlier C5's which covers a lot of ground but it doesn't cover any revisions and changes after the facelift Mk11 and certainly doesn't go down to the level of technical description of reservoir cap :-)
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Re: Citroen C5 Mk II Suspension Will not rise

Post by howardaskew »

cachaceiro,

Thank you for your reply. I am looking to source a replacement pump unit and then will set about refurbishing the old pump motor.

My reasoning is as follows.

1) Pump when running sounds slower than my MK 1 and the interior light dims when pump is running. This could indicate that the mechanical part of the pump is in good condition and places a (heavy) load on the weakened motor.

2) The mechanical part of the pump is worn out/partially seized and places too heavy a load on an otherwise good pump motor.

I think scenario 1 is more likely than scenario 2.

But with a full investigation I should be able to find out which parts are subject to wear and refurbish. The companies that rewind motors (starter motors?) should be able to repair the motor. I may even be able to source a new electric motor.
I will keep this as a good spare if I am successful.

I will keep the forum updated when I actually complete the repair.

It will not be for 2 or 3 weeks.

Many thanks,

Howard