Hi xmexcl,

I see what u mean, but I think for the mass of the car to continue straight due to inertia would take effect at speeds nearer to, e.g., 120mph. At 120, yes, I agree that the car's body would pass flat over the same hole, i.e. you would realise less that there was a hole. But at city speeds clearly the body has all the weight to "look for the ground" if suddenly the wheel stays in the air. How much time 400kgs need to start falling? And, as u say, that corner *will* be pressed from its diagonally opposite, at any time when crusing straight. You can experience this with most conventional cars anyway. My said Clio felt like it "hunted" for the holes with every wheel. Similar I felt with a Polo I recently drove -very firmly damped on expansion-you would think the car was "magnetised" in the various wholes. After driving it I thought it was like a little goat, jumping here and there from hole to hole!

I suspect LHM cars are crashy not because of the natural specs of the hydropneumatic suspension but because Citroen has originaly chosen a policy of minimising the rubber element in its suspensions, and trying to achieve most flexibility from the sphere. Early BXs had bearings instead of rubber bushes, if I'm not wrong. Typical rear arms are totally inflexible to move in any other direction than rotate -I read somewhere about the precise value for slack they incorporate from design, it was ridiculously small, like microns or so!-. That's amazing for driving precision but only if everything works perfeclty. My Clio with hard springs etc is also very hard but not crashy, because it relies more on rubber here and there, I guess. The effect with a sticky strut may be exactly as u describe: in some situations the strut top rubber becomes the only suspension but it was not designed to be as such, so u get this awful crashy vibration. Currently the automotive industry has taken the other direction: tyres as low profiled as possible and much elasticity from rubber in the suspension. My friend's BMW e39 520 is surprisinlgy comfortable with small irregularities; the rear suspension contains so much elasticity that you can actually see the wheel moving slightly backwards when it initially meets an obstacle, as a first step to smoothen its absorption. Of course you loose in precision.

I hope by middle June I'll have my new rear cylinder fitted to see what it gives.

regards
George

Hi George

The results of your new cylinder will be interesting. I have problems in understanding why virtually the whole weight of the car should transfer to the floating wheel with the sticking strut. It is more likely to try to spread between the other three wheels. The two wheels on the opposite diagonal will take their load equally as designed but the other rear wheel will have hydraulic pressure without a balancing force from the floating front wheel so by trying to take more load it will just tip the whole car diagonally and the still floating wheel down into the pothole and the crashiness is when that wheel hits the far side of the pothole.

Regards

XMexc

Hi xmexcl,

Not the whole weight of the car, just the weight of that corner probably acting. My XM is 1425kg and 63% are at the front axle, so each wheel gets about 400kgs. Anyway, we'll never proove anything safely like this as we don't have numbers, formulas etc. But just think of reality: cars with harder suspension fall into holes all together, their wheels do not fly over the holes.

If the cylinders fail to correct the problem, I'm out of solutions, except of the senario where hydractive blocks are badly blocked with muck and LHM does not flow well -and flows better when weather is warmer and LHM is thinner-. The ultimate test always available is to remove my hydractive block and replace it with a cleaned one, where I will have blocked the hydractive valve into open with a piece of plastic or copper tube -it's very easy if u have it off car-. If then it continues to be not good, then I don't know...

regards
George

George - find another XM, test drive it, confirm it's a good one, sell your current car.

I completely understand your desire to cure it yourself but you've been pursuing your suspension problems for so long I'm getting concerned for your sanity

hehe...have faith...the end of the tunnel is near!!!!

Gosh, if I had £1,000 to spend I'd just order my indy to put new hydraulic-all elements in a day and I'd have a brand new spanking magic carpet!

Thanks for condolences anyway!!
G

I can't fault your determination or fault diagnosis by elimination

A question has just sprung to mind..........given that we all love these cars.....if brand new XM's were being made right now.....would we all buy one???

What a lot of posts since I last checked.

The descriptions of the 'crashy' feeling are spot on. If you go over a speed hump, the suspension first takes the change in height, and then the car follows gradually. But not so with pot holes etc. When I hit a pot hole (and there are lots of those around me in surrey) the whole car drops into it (even though the hole may only be a few cm deep) and then jumps out of it again.

Damaged road surface (and again there is lots around me) gives a real juddery feeling and lots of road noise with it.

I occasionally get a ride in a Rover 75 on the same roads I drive every day. It has much harder suspension - you feel every bump/undulation in a way I don't in the XM, but in a much softer way. You feel the pot hole, but it doesn't jar your back. And the seats seem much firmer in the 75 so I don't think it is that.

Perhaps I notice it more as the roads are so bad around me. That is a completely different gripe though. It seems Surrey has a now started a policy of not paying out on damage to cars due to road condition (ie pot holes and damaged wheels/rims) unless there is direct evidence of incompetence on the councils part. In the approximate words of a representative to a local paper 'you can't expect us to know about every pot hole as soon as it appears, or fix them immediately when we do know'.

I will have to try dropping the tyre pressures a few PSI and see if it makes a difference.

Cheers,
Rowan.

Hi Wirdy.

Would I buy a new one ? No ---- but then again, I wouldn't buy any new car with my own money. Been there, done that, lost the dosh ! I think the snippets of conversation on the forum regarding the C6 tend to show we're all waiting for the prices to collapse before having a play and I reckon new XMs would be the same.


Mike.

hi everyone

I saw a c6 for sale a couple of weeks on the net somewhere, and it was around 10k down on the new price!!! it seems like the xm all over again dispite citroens garantee to buy the vehicle back! But then i suppose who wants a 2nd hand luxury citroen..........apart from me.
at least if they loose that sort of money 2nd hand it just means i will be able to afford one sooner.

I remeber when the last version of the CX came out, with the radio mounted vertically between the seats and the motorised suspension height switch. I desperatly wanted a diesel Safari and I used to go to the motor show every year just to sit in one! There was no way I could afford one until one day I saw one advertised in London, for much more than I could really afford, but cheaper than I could ever hope for. I borrowed the money, it was about £5k! and bought it. The first time a I pushed it hard up a hill it blew all the water out, that was the start of a regular six monthly head gasket change, but for all that I loved that car and ran it for seven years and about 160k. By that time, the XMs were just about affordable and I have been running them for the last eleven years. I cant see that happening with the C6 though, my critera is estate and manual, neither of which they make.

Peter.N.

Guys, as much as I like a C6, I'm not prepared to handle the emotional stress of diagnosing its faults. Have you seen the suspension? It's an hydractive like the XM (okay, the C5), plus it has another system on top for controlling damping -each corner sphere gets 7 different damping positions within miliseconds by means of a blade sliding over the damper wholes with the aid of magnetism-. Amazing, excellent system indeed but....no, no, and no. I can bet anyone who likes, that 20 years from now they will have all been equipped with comfort or CX spheres from the then owners to counteract the OS suspension -"stuck in super-hard" I will be calling it then....-.

Not to mention diagnosing the rest of the car's electronics -but this is common to all modern cars-...

On a more positive (...??) note, I took the plunge today of buying a new front cylinder from ebay-France, so with the new rear one I will be able to test the whole system....I pray it's the correct part, ebay is bad when the part is the wrong one. According to parts catalogue it seems it's the right one, and I paid overall £107 when a new one overhere is about £160+vat.

Rowanmoor, unfortunately I've played with pressures (e.g. put from 18 up to 32 in front) but crashiness always there.

cheers
George

ps. anyone has a good storyline for my girlfriend for when the postman brings the cylinder from France?

in my experience, there is no excuse/story in existence that can hide a bank statement!!!!!

Hi George

Let her open the parcel if she has a mind to. She may not be too interested in a cheap useless piece of car junk but if she is give her a copy of Haynes and let her fit it.

Regards

XMexc

The main difference between a wife and a terrorist is.. that you can negotiate with a terrorist.