Hi all

George, you are probably right about hydranet then, it is probably a happy medium between petrol and hydraflush ie kind to the rubber parts but better at breaking the crud down. when i get back to work on mine i was planning to refurb the dist valve, so i will see how much crud is in there, like you said the filters will probably be bust because if they block ,the pressure will just blow the filter mesh straight out. Cant wait to get started on my car now, i have the new decat section that i have welded the oxygen sensor boss onto and the re built and polished cylinder head,inlet manifold and throttle housing, new belts, ball joints, engine mounts, it will be like,......well actually most of it WILL be a new car
Wirdy, the filters in the dist valve will be down stream of the pump and pressure regulator, the pump will not hold any crud ,at least i have never seen a dirty pump, but the pressure reg can get very dirty, considering it is only the second component in the system, i wonder how much can get caught in components at the end of the circuit! anyway I'm thinking when a cleansing agent is added, the dirt in the pres reg would be gradually washed out and caught in the distribution valve filters, also i think the accumulator sphere, when depressurised returns its fluid via the dist valve but not 100% sure on that. But as you said the fluid from the rest of the system is returned via low pressure rubber piping and a filter, back to the tank.

Dean

Hi all

Just a very happy update on how it goes with mine.

Yesterday I took the car again after 5 days of not having driven it, and it had become even softer. It is amazing now -I think it cannot get much better at the front-. Specially the front is a fantastic, you can really feel that the struts respond to any ground anomally completely free of sticking or anything. The slight judder still felt on "reception" of a hump-like change in tarmac surface is now totally gone, to the point that you could graph the car's body motion as a perfect curve, while before, there would be still a little "spike" at the moment of the wheels first meeting the object . You can feel it is only the spheres working now! I was so happy, I went and repeatedly passed the car over a local speed hump, just to enjoy. You might say, "Ok big deal, speed humps are everywhere". But *I*, didn't feel like doing that, till yesterday. Believe me, it brings a huge pleasure to somebody that has driven his car for the last 3 years almost in an "anal retentive" manner, for the fear of getting the strut tops through the bonnet and for trying preseving his car's general state; unconsciously tightening the teeth whenever I saw a bump approaching was how I've been feeling everyday. City was my nightmare, full of bumps and holes... Now I get back the pleasure of throwing the car wherever, at whatever speed.

The other issue I was thinking about is the now confirmed fact that it improves in distinctive steps, which, as far as I remember, appear each time I go and take the car again -not in the middle of a trip or so-. Maybe when I drive it everyday the hydraflush/Hydronet2000 mix, doing its job, becomes full of operational dirt, but then when I leave the car for a few days, the dirt settles down in the LHM tank and the oil becomes again....more of an oil, so the improvement comes to surface.

I'm now at 9,500km on cleaning mix. The last couple of weeks the new thing I'm doing is slaloms -on motorway, and in neighbourhood-. I happen to get back from work as late as 11pm sometimes, so I take the opportunity to slalom it smoothly on the empty motorway, just using 1 lane, not anything dramatic. The objective is to do it as smoothly as to not activate the "hard" mode, as then the right-left crossflow passages are cut. I do this to make the oil crossflow and thus thoroughly clean the hydractive blocks. I've always done and still do lots of ups-downs everytime I stop somewhere, but I thought this doesn't really clean *all* the parts of the hydractive block. Also, just doing it at a low speed -say, 2nd gear- should be equally effective as long as the car rolls -I don't recommend doing it on the motorway unless u r mad-.

Now, I'm not saying the last improvement was related to the slaloming, but personally I believe it was. As I'd written in the first place, symptoms made me think of a blocked crossflow in the hydractive blocks, together with sticky struts. As it is easy to understand from looking at a shema of the suspension pipes, Citroen's hydraulic system (not only Hydractives) works pretty much on playing with the crossflow between the two sides of the car. Much of the comfort perceived comes from this feature, it's not only because the spheres' spring rate is softer than the average car. In reality when a wheel meets a bump, it also takes advantage of the sphere of the other wheel, not only of its own sphere. In practice, this system owes much of the comfort in its inherent characteristic of translating part of the vertical movement of one corner wheel to a vertical movement of the other side wheel, and to an opposed direction. This makes eg the front go up altogether when one of the front wheels meets a bump, reducing further the feeling of the car being perturbed. In a car with coil springs, because of the antiroll bar, and because springs are...dumb, the effect is the opposite: when one side is compressed, the other tends to compress also, multiplying the effect of the bump!!!! In my car the effect described is now absolutely obvious. I pass everyday from a piece of road perfect for demonstrating this: the tarmac is full of random continuous bumps and holes, but what you get is the front axle and the rear moving vertically up and down, parallel to the ground, not a hint of the car shaking left-right as the bumps come. I should really make a video of this.

I'm also thinking, before putting fresh LHM, of making the oil run from each corner sphere bracket for a while (sphere off), engine running and car trying to go up. I will be sending the old mix to a bottle (will use a cut balloon as adaptor from sphere bracket to pipe), while adding fresh LHM in LHM tank. Even if u put car to low, the hydractive pipes remain full of the old stuff, and they are sizeable-. I don't want anything dirty stay in there!

The car goes beautiful now, specially taking into account that a year ago I measured my spheres and they were all about 10% down. Again, the 2 huge differences I note as it's getting better and better:

1. the motorway stability to winds, lorries passing etc is amazing now -nothing seems to move the car out of its trajectory, while you only feel the body moving slightly from the wind blows-. Been driving with gales the last month here in Scotland and you do notice the gasts of wind pressing the car down, specially the bonnet with its large surface. Lorries also have 0 effect on car. Before I had been very dissapointed with this point in the XM -I was thinking probably the worst aspect of the car- it was totally nervous in these conditions, more nervous than a bicycle would be!

2. the feature that I had never noticed before and has happened about 2 weeks ago for first time is that, when car is on highest, and I move the lever to lowest, the side of car where I am seating reacts a *tad* faster than the other side -you can see it with your eyes and also feel it-. So the other side starts dropping *just* a few miliseconds later. This behavior I now confirm is permanent. If not anything else, it shows how few the struts stick now -or how much they used to stick before-: they are now sensitive to my wheight (only 70kgs, 9 stone). I have to remember checking if with a passenger both sides will drop equally fast or still my side will "unstick" faster, then it would mean the other strut is more sticky.

3. if your XM's plastic interior shakes so bad in bumps that it makes you think the bits and pieces are ready to fall off, then def. you've got a suspension problem. It normally doens't produce any noise at all. I would suspect that this is partly responsible for the held perception that "S2 cars are better screwed together", i.e. unmaintened S1 cars just because of age tend to have more often a not-working-well suspension.

So these are 3 of the things to notice for somebody that thinks his XM is not as it should be. Again it's nice how the car, although softer than anything, is not wallowing etc like a boat, but instead feels completely composed and steady. It is smooth in a way that cuts a great degree of the feeling of acceleration -the needle goes up but you remain as cool as it can be-.

I now feel like making some videos of the car working in various circumstances, for youtube, very soon.

cheers
George

ps. Have not heard from the Hydronet people yet.

some more info about what we put into our cits

http://www.candokaraoke.com/tony.html#Flui...or%20LHS%20Cars

and can i put me name down for some of the hydronet 2000 please

ta

Very interesting link Charlie.

Ok, I've put your name down. Still have not heard from them, yesterday I sent a reminder, let's see, next will be a call to France.

cheers
G

George,

Could you put my name down for some please?

Cheers

Ciarán

Ok Ciaran, done.
G

Hi all

just took the car again after it had sat since Wednesday. Today I did an experiment, I wanted to see how it performs with LHM instead of the flushing oils. I've been adding about 0.5lt of oil each month as I have a leak and each time was putting different proportions of hydraflush, Hydranet and LHM. So this time I only added 0.5lt of LHM, and topped it to the max. It is working wonderfully, what a good surprise. Later as I arrived to my destination and tried to park in a crammed park I decided I would put it in a slightly off-the track area at the edge. But there was a slight downward step of about 10cms on my way so spontaneously thought "I better lift the car" and put the lever just to "intermediate high" as I was crowling and about to touch the "step". I was surprised at the speed the hydraulics reacted, literally in 1-2 secs the car added height and I passed the object comfortably and parked -did not even need to brake and wait for it to lift itself-. Everything hydraulic seems to work so much better now -it's not only the height correctors, it also affects the reserve and supply of pressure-. Trust me, this feature was of no use when I got this 138,000 miler car, this would have needed 1 minute to happen -if the height correctors reacted at all...-. Now it's a proper usable feature of the suspension! I cannot imagine it happening faster with the electric pump/valves of the new Citroen generation.

As I was in the supermarket car park I took 2 videos with my mobile doing the same thing as the guy in my signature. I'll post them here later.

cheers
George

OK, I'm convinced, if there's any hydronet 2000 left I would be very interested in some, preferrably enough for 2 cars. Will probably try on the old one first as it leaks LHM anyway.

Oh, and when you're ready with those videos....

regards

Ok DrTim, put you down.
G

Ok, here are the 2 videos of me pushing my car. The quality is bad and you will have to tilt your head, but they were not planned. I'll soon do normal quality and more extensive videoing. Still, you get the idea:


pumping the rear


pumping the front


Mind you, opposite to what you might think the video shows, to that day the front performs better than the rear!! The rear has not followed the front in improvement with respect to being able to deal even with the most sudden bumps/holes. Although very soft and fine in 95% of situations, when something very abrupt comes it still is "crashy", while the front is "rounding" 99% of the things you'll meet on the road. Clearly the cylinder cannot move fast enough -this is well demonstrated on a couple of motorway holes I pass everyday: the front wheel moves satisfactorily and falls in the hole, then the rear wheel doesn't and makes the car fall in the hole-.

There's no doubt the rear middle sphere is *in* circuit though, e.g. it "bottoms out" like a real Cit when starting up from a traffic light. However I was thinking perhaps because the rear cylinders work less than the fronts, and also have a smaller actual travel, the flushing has done less of a job overthere. E.g. the slaloming I do lately, that seems to have done so much good, obviously works the front much more extensively.

That's why I was already thinking of starting doing also some reverse-gear slaloming. Then I read DrTim's indy suggestion of violently braking going in reverse. So that's what I did last night in an empty car park, in various versions. I did a number of straight line braking -about 4-. Then I did the same but also steering at the moment of braking -another 4-. This was fun, in the last version the ABS came in every time.

Then straight afterwards I tried doing ups/downs as described in the other thread, with the suspension ECU off and suspension in "hard". It was funny....First of all, car is lower to move than when doing the same in "soft", both directions. I didn't count, but perhaps almost double the time. I did about 15 cycles. I think it moved a bit faster towards the end, but I'm not sure. There's obviously more resistance in that path: the front took 4-5 regulator's cycles to reach "highest", this means the pressure regulator has felt 4-5 times a pressure of 170 bars counteracting it. In my car it will only click 1 time or not at all to get it to "highest" with suspenion in "soft". For now I'm not able to know if this increased back pressure is because that path is narrower or because it is clogged up. I suspect a bit of both. It will show as I continue the routine.

Second, on the way "up", a loud "whistle" was produced by the car, somewhere at the rear, till it got to "highest". Then this would stop, and the front would start rising. This whistleling made me laugh because I had had it when I had first bought the car, before I ever used hydraflushed it. It did it -louder also- at exactly the same circumstance, i.e. when having put car to "lowest" and then to "highest", frightening people around. Obviously this is something to do with LHM passing under pressure from a passage it shouldn't pass. So that was either noise from the point I was putting under stress for the first time (the ball setup in the hydractive block) or the rear height corrector leaking. It wouldn't be the rear e-valve as this was "closed", the suspension being in hard (they are only known to develop a leak when in "open" position).

Third, the most striking (and worrying) effect is that the pressure regulator was clicking in very small intervals afterwards, like in the past before I ever put hydraflush: about 14secs, instead of 25+ which I had achieved with the flushing. This cycles of 14secs came for the first time after that devilish day in March 2006 when I had the car for 2 hours on "highest" engine running -just prior to that it had been doing about a minute-. The good news is that, with yesterday's experiment, I am able to say that 1/it is NOT the rear cylinders, 2/NOT the e-valve, 3/NOT the brake valve. All these items I was worried I destroyed because of exposing them to high pressure for 2 hours. But yesterday, the only items that received all the stress (pressure) are the height correctors being in the middle of high pressure between the accumulator sphere and the small AND/OR clogged alternative passage of LHM in the hyractive blocks.

Now, despite the pressure regulator cycling times having fallen to 14 secs (bad), the suspension's softness didn't look like the middle spheres were not opening. The opposite, on the way home after these routines, I have trown the car with a pleasure I don't remember doing since that single day in 2006 when it was working as it should. Because, one discovers, when the thing is workign as it should, it is not simply the comfort that improves, it is the whole hadling package -it becomes like a 5 meter GoKart-. This event with the regulator clicking at 14secs proved what I have evidenced in other stages of this process, when the cycling time was ranging between 14 and 28 secs on a daily basis, but the softness remained absolutely the same: that, for getting and keeping the hydractive piston valves OPEN, it is much more important to get the pressure regulator tuned correctly (145-170bars) than to achieving a long cycling time. This would prove definitely that even if your cycling time is excellent, i.e. 1 minute, if the pressure range provided is below the specified, chances are you will have a hard suspension because the hydractive pistons cannot be pushed open. Also this finally proves that the critical thing that happenned to my car in 2006 was not that I created a huge leak of pressure, but that parts of the system got dirty and sticky: last night I had again a 14sec cycling time, but the car was comfortable almost like before I...damage it. In one small speed hump -u know, the thinnest ones from plastic- the rear has passed like cream, while till yesterday I would expect it to shake the car. Pitty I cannot know if this is due to the violent rearwards braking or to the ups/downs in hard mode.

I think overall this is excellent news. I'll probaly strip and clean the rear height corrector or put a new one, come summer -looks like it doens't shut entirely or just the piston leaking above a pressure point-. Can't wait to take the car again this weekend to confirm the changes -it's always a bit worse just after doing ups/downs-.

cheers
George

I didn't realise there was an almost parallel thread to mine going on here. I tend to ignore anything that says '2.5'. Anyway, all very interesting especially the explanation of the system function and pleased that you've got it sorted now.

Peter.N.

In

http://club-xm.com/forum/index.php?showtopic=3131&st=40

Steve wrote:

The 'christenings' are quite a celebration aren't they? We had a great time. One or two of the British commented about the dipping and how it made Andoni cry but my attitude was it's his right of passage and his culture, his sister Anastacia didn't bat an eyelid.

As for the food where do you start? My favourite is Stefado. That said I'm quite keen on goat meat. Maybe I'll make that BBQ.

Steve.

Hehe stefado is my latest success! My girlfriend's favorite also!

As for christenings...guess who is the brave man below... :




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Hey ! Pretend you haven't seen my willy huh!

cheers
George

ps. Note the yellow Fiat 127...900cc...our family car for nearly 13 years! Sills done twice over that period and that's in Athens! Would have survided about a year in Scotland.
My sister and I cried rivers when we finally sent it to the scrap yard...

Nice er... photos.



Athens, it must get really hot down there. I've only been as far south as Halkidiki - where the inlaws live.

As for XM work, let's see what the Easter break brings. Plenty of wiggling (!) and 'press ups'. Oh and some more hydroflush.

Happy Easter!

Steve.