C5 spheres

[Peter.N.]

I thought I had better start a new thread for this one. On my newly acquired C5 the rear suspension is nice and spongy with about 6" of movement, the front seeems very hard an moves only an inch or two, I know the front is normally harder but is this normal or do I need new spheres?

Thanks, Peter

[addo]

As mentioned elsewhere, once C5 spheres drop below a threshold pressure they self-destruct - a spike inside pierces the diaphragm. Perhaps one of the front two is dead?

[lexi]

You'd be dead too Adam if a spike pierced your diaphragm.

[cachaciero]

This is a 2.2 does it have H3+? can't remember sure Paul would know anyway if it has a "SPORT" mode switch then it does and as a result it will have a center sphere which may be shot or the regulator may not be working correctly.

cachaciero

[Peter.N.]

Yes it does have a sport button but if the system was faulty would it not affect the rear, the suspension is lovely and soft there. There is some suspension as it still rides better over our forest track than the 406 does but it does feel like an XM with low pressure spheres. How much movement should I have on the front? Does the centre sphere give the soft ride as on the XM?

Peter

[cachaciero]

Yes it does have a sport button but if the system was faulty would it not affect the rear, the suspension is lovely and soft there. There is some suspension as it still rides better over our forest track than the 406 does but it does feel like an XM with low pressure spheres. How much movement should I have on the front? Does the centre sphere give the soft ride as on the XM?

Peter

Would it affect the rear? unlikely mechanically the system is pretty well identical to an XM in terms of a system operationally a bit different.
There is in Citroen speek a regulator on each axle which is the equivalent of the centre electro valve on an XM. The centre sphere screws into the regulator.
The operation of the regulator is similar to Series 1 Hydra-active in that it is either energised or de-enegised soft is de-energised and is the normal mode. The regulator is controlled from the BHI (Pump Unit) and comes in for various combination's of speed and steering.
You can test it by using a Lexia which has the ability to both test the regulator and to allow you to drive it so you can prove that the suspension goes stiff.

The rear regulator and sphere is easy to get to, the front a bit of bitch, there was a thread a few months ago which discussed this and some body woody? gave a good description of how to change the sphere, big problem if on low ramps is getting enough leverage to undo the sphere.

cachaciero

[Peter.N.]

Thanks for the explanation. The real problem I am having is trying to determine whether the spheres need replacing, the XM has a great deal more movement on the back than the front even with new spheres, I can only push the front down a couple of inches. I have a home made ramp that gives me good access to underneath, from what I have seen of the car so far it looks easier to work on than the XM or 406 - but probably not for what I want to do.....

I am hoping to get my Lexia going, another member is kindly sending me a programme disc that works! Especially in view of this 'light on MOT failure' that's looming.

I have just had to jack all four wheels up to take them for new tyres' the ones on there would give me enough points to loose my license.

Peter

[cachaciero]

Thanks for the explanation. The real problem I am having is trying to determine whether the spheres need replacing, the XM has a great deal more movement on the back than the front even with new spheres, I can only push the front down a couple of inches. I have a home made ramp that gives me good access to underneath, from what I have seen of the car so far it looks easier to work on than the XM or 406 - but probably not for what I want to do.....

I am hoping to get my Lexia going, another member is kindly sending me a programme disc that works! Especially in view of this 'light on MOT failure' that's looming.

I have just had to jack all four wheels up to take them for new tyres' the ones on there would give me enough points to loose my license.

Peter

Yes well you have the same problem as I have my front feels hard and is as you describe, trouble is I have a problem trying to discern if there is any difference when actuated, my feeling is that it is a little stiffer but I ain't really sure. I changed the front strut spheres and it made no difference C5 spheres really do have long lives and it is for that reason coupled with the difficulty of access that I have put off changing the center sphere.
You will have to drop the under tray to see the front sphere, left of center looking forward on top of subframe x member.
Getting your Lexia working would be good
If you PM me with an e-mail add that will take big attachments I can send you some stuff that you will find of interest.

cachaciero

[kenhall1202]

Thanks for the explanation. The real problem I am having is trying to determine whether the spheres need replacing, the XM has a great deal more movement on the back than the front even with new spheres, I can only push the front down a couple of inches.

Peter

Hi Peter

The only way to be sure of your front spheres condition would be to take them off and pressure test them - something the Lexia can't tell you! The neck thread size is common across all spheres so anyone who has built a tester for XM spheres could help, including me, but I'm a bit far away from you unfortunately.

Ken

[Peter.N.]

Cachaciero.

I understand that these spheres last well but the car has done about 150k so I am wondering if at least the the front centre needs changing, The rears feel fine but I have noticed that the fronts on the XM go first, presumably because of the extra weight. I will PM you my email, thanks.

Ken

I have now fitted the new tyres and have it insured from tommorrow so I should be able to get a better idea of the ride. When I brough it home from Exeter it sounded very noisey on the concrete section of the A30 but whn I got home I found the tailgate was open.

Peter

[Clogzz]

My C5 with the lighter petrol engine only pushes down about an inch, with clicking sounds coming from the spheres.
That’s with the engine stopped and both hands pushing down on the metal outside the top of the radiator.
The ride is good, with a fair bit of front suspension travel on the bumpy old roads.
The rear easily pushes down several inches.

[Peter.N.]

I have been out in it today and the ride seems to be quite good, certainly better than the 406 and the front doesn't seem to crash down holes any worse than the back so maybe its OK. I might be going up to Doncaster in it at the weekend so shall be able to give it a proper test.

Peter

[uhn113x]

I don't know if C5 spheres are similar / same as the earlier sort, but it was easy to test those without any equipment. With the sphere removed a thin rod gently pushed through the output hole will go all the way in if there's no pressure; the slightest amount of pressure will push the diaphragm against the hole.

Might be of use, might not but good luck.

If you're going as far as Doncaster, Golborne is not a million miles away!

[Peter.N.]

I remember Golborne, if its the same one there used to be a commecial vehicle breaker near there by a railway sidings something to do with coal. He used to break lots of vehicles with Perkins 4/108 engines that I used for car conversions, I was always buying bits of him, I think he died and his son took over - this was some years ago mind.

Peter

[uhn113x]

I think it was a place where I got a set of injectors for a Leyland coach owner friend in the 1970s - on top of a small hill up a rocky lane. Probably well gone by now.

No, it was actually the Vintage Radio event tomorrow I was referring to. I'll be there.