Strut Compatibility, C5 to XM S2?

It might be that I will have to change both rear struts due to internal pressure drop in the system which causes the electrovalve to trigger every few seconds. My serviceman says that it can also be the rear break valve (another symptom is the rear end sinking in a matter of half an hour) but I want to be prepared for the worst. Are C5 struts compatible with those of the XM S2 as they are considerably cheaper than the original parts and, if yes, are there any downsides to them in terms of performance, comfort etc.?

Thank you.

Hi,

A far guess here, but i would say no...

The C5 useses a new YELLOW hydraulic fluid now, thats completely different to XM fluid, this i guess would make it a no.. It may however only be a problem with the sphere seals..

I would be more inclined to think Xantias ones would do the job...

Thats my initial thoughts anyway.

Rgds

C

not sure that the fluid difference would be an issue, C5 spheres have been used with LHM systems, but you'd need to flush it thouroughly to remove all the other fluid before use.

Given the age of your car, sure it's not the anti-sink sphere that's the problem?

just a thought
Dave

Hi John,

I may have missed it if you've been talking about this problem elsewhere. However, there seems to be a few mixed up symptoms and conclusions in your description.

Leaking rear struts will not cause the rear electrovalve to trigger every few seconds. Indeed the leak, if it exists, will not have anything to do with the electrovalve. The electrovalve simply opens and closes and allows the middle sphere to connect or disconnect from the hydraulic circuit. The device which will be affected by strut leakage is the height corrector and ultimately the regulator/pump at the front of the car.

Fast sinking overnight is a combination of Anti-Sink sphere (empty), leaking Anti-Sink valve, leaking FDV or badly leaking rear struts. The Anti-sink valve isolates the brake valve from the circuit when it closes. Therefore, if the brake valve is to blame then the anti-sink valve must also be broken. However, I don't think this is where your problem lies.
If the rear struts do leak badly and there is no LHM on the path then, by definition, it must be going back to the reservoir. Go underneath the car at the rear, pull off the plastic return pipe from each rear strut and watch for lots of fluid coming out of one or both. If the leak rate is very small then the rear struts are not your problem. The problem is with another hydraulic device.

Can you please explain more about the symptoms so that we can help you find the best answer to your problem?

Cheers

noz

Do you mean the pressure regulator?

This might be relevant - not entirely sure how, but it appears the electovalve can cause similar symptoms in certain cases

Electrovalve

Hi All

According to John M's signature his car is a 97 V6.
My 96 V6 is without anti-sink.
I did not think even the later V6's were fitted with anti-sink.
Worth checking as it might be that the car should settle overnight anyway.

Regards

XMexc

I apologize for my yesterday's absence but here are my symptoms in more detail:
1. The valve at the front part of the car triggers every two seconds
2. The rear end sinks in 30 minutes or sometimes even less after the engine is turned off while the front end cannot survive overnight either. The rear end sinks a bit on a traffic light
3. The car doesn't lift smoothly but in pulses
4. When the rear end sinks, sometimes I find it inclined, with the right side higher than the left
5. When I turn off the engine, there is a whistling sound which stops if I turn the steering wheel

The following has been done on the hydraulic system so far:
- regulator and electrovalve replacement (after both replacements, the hydraulics would restore normal operation but aftere a couple of hours it would return to 2 sec triggering and other symptoms described above
- checking of all spheres
- sealing and checking against external leaking - not a single drop underneath the car
- currently driving on Hydraurincage flushing fluid

The car was actually bought at Belgrade's Car Show in 1997 and the serviceman claims that its hydraulic system has been working in this way since the beginning, showing me the documentation and correspondence with France on this matter. Although not the first owner, I am now determined to correct this problem and any advice on how to solve it and outplay Citroen S.A. themselves is warmly welcome!

This post has been edited by John Malkovich on April 01, 2008 09:04 am

Hi John,

Taking your symptoms one at a time:

The valve at the front part of the car triggers every two seconds
Presumably you mean the main regulator? If so then this points to either a flat regulator sphere or a very large consumption/leak of LHM by one of the hydraulic circuits.

The rear end sinks in 30 minutes or sometimes even less after the engine is turned off
XMExc says your model probably does not have anti-sink. Therefore this may actually be OK. You would need to compare the sinking time with another car without anti-sink to determine if your car had a problem.

The rear end sinks a bit on a traffic light
Thats a problem. However, it sounds like a lazy rear height corrector. This can be caused by a sticky mechanical connection or a very worn pivot between the anti-roll bar and the heght corrector.

The car doesn't lift smoothly but in pulses
This is absolutely due to broken diodes in your electrovalves. The solution is quite simple - add two more diodes to the electrovalves ircuits. Search club-xm for "diodes" and you will find a lot written on the subject including a self-help file in the self-help section. Otherwise you can buy a ready made kit from one of our members "mackay1"

When the rear end sinks, sometimes I find it inclined, with the right side higher than the left
This sounds like the rear swinging arm bearings are worn and sticking. Nothing in the hydraulic circuit would cause this problem unless one of the hydraulic pipes has collapsed.

When I turn off the engine, there is a whistling sound which stops if I turn the steering wheel
The whistling sound is fluid leaking out of your regulator quite quickly. If it stops when you turn the steering wheel then it sounds like the leak is in your FDV (Flow Diversion Valve). The FDV leak is a reasonably common issue. Search club-xm for FDV to find out more.


If no fluid leaks onto the ground under the car but the pump is pumping a lot of fluid then the leak is from the faulty device into the return piping and back to the reservoir. To determine which device is to blame, remove one pipe at a time from the top of the reservoir with the engine running. The one with a lot of fluid flow is connected to the faulty device. Each pipe connected to the top of the reservoir is connected to a particular device. If you know which tube has the excess flow then you can tell very simply which device is leaking. I can post a diagram to show you.


I hoe this has given you some food for thought. Please respond with any other questoins/symptoms so we can help you solve your problem.

Cheers

noz

When you say the rear end sinks a bit on the traffic lights, are you applying the parking brake or keeping the foot brake applied whilst waiting at the lights?

If you are using just the foot brake then what happens is the car rises slightly at the back when coming to a stop but because the foot brake is applied the car can't settle to normal height (because the wheels are locked by the brakes). The height corrector senses that the car is too high at the rear and diverts fluid to lower the rear of the car, this doesn't have any effect because the wheels are still locked by the brakes. However as soon as the foot brake is released the rear of the car sinks because there isn't enough pressure to support it. The solution is to either use the parking brake or release and reapply the foot brake. This is the reason the parking brake is on the front wheels.

Sorry if you already knew this some new owners don't.

Steve

Thank you very much for your exhaustive explanations. They are all very logical, particularly observing the quantity of returning LHM in various hoses. I wonder why the service hasn't tried this but I have already scheduled the visit for Friday morning (replacing the tracking rod ends) and with some friendly persuasion, he'll do it (are only Serbian technicians so full of vanity?).

Regarding the sinking while waiting on traffic light, I am aware that it will happen always if stopping under foot brake and then holding it. However, after stopping, I release the brake, thus allowing the height to correct, I engage it again and after a minute it will go down another couple of cm. The only thing which bothers me is if the car is safe against bumps and is it OK for long distance driving in this condition.

This post has been edited by John Malkovich on April 02, 2008 10:27 am

Hi John,

My '99 V6 has antisink and started dropping its rear end down to the bump stops within a few minutes of stopping. I also found that when I was sitting in traffic, by looking in the rear-view mirror I could see the rear end falling, then rising, then falling... etc.

With antisink it obviously could not be a fault in the height corrector or brake valve. Checking the return lines found an internal leak in one rear suspension unit.

Derek

Hi again John,

Further to xmexclusive's comment about antisink possibly not being fitted, the easy way to check without getting under the car is to take a look at the hydraulic pump.

If it has only one pressure outlet you don't have antisink; if it has two, you have the 6+2 pump and antisink will be fitted.

Derek

Silly question.. mostly from recolections of my first XM and S1.5 SEi...

It did many of these things when I got it.. the whistling, constant ticking form the regulator and sinking in near no time. I found the pressure release on the FDV was not fully done up! did it up and all the above faults dissapeared, although the car woudl still sit down at the rear over time, it took a lot longer. The previous owner just before I got it had just rebuilt the FDV...

Stewart

Hey! you are cheating, that's too easy!!!!

Yeah cheat, these problems are supposed to drag on for ages and cost loads, you cant just stroll in with an easy fix

Dean