Stepdown Hydraulic Bushings (Xantia)

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Stepdown Hydraulic Bushings (Xantia)

Post by addo »

Has anyone seen, made or improvised bushings to adapt various Cit hydraulic line sizes?

I'm thinking about replacing the skinny non-Hydractive feed lines with Hydractive size tubes off a wreck (allowing later conversion to Hydractive/Activa).

Regards, Adam.
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Post by DickieG »

Why :? is life that boring down under?

The larger Hydraulic pipes will take some effort to bend into shape.
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Post by addo »

Life's only boring if you want it to be! :P Xantia are few and far between (thought one was following me yesterday, but it was a Xsara). Given the state of our roads and the distances I regularly travel, some degree of control over suspension settings would be nice.

I have access to a donor Series II with Hydractive that was T-boned. Due to downtime constraints, it is sensible to fit parts incrementally. So, an inline bushing isn't going to necessitate rebending of lines - it'll just space out the fitting and hose by maybe ¾" each end.
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Post by AndersDK »

Before you consider any mods - you are aware that the pressure lines are carrying a hydraulic pressure up to 170bar - or more than 2500psi - ??
Its not eaxctly the same job as messing around with brakes piping.

You dont need the hydractive large pipes other than the run between wheel cylinders and the central axle sphere unit.
This pipe run must have a large diameter (10mm) all the length including unions, as the hydraulic fluid moved by the cylinders are running through these pipes to enter the center sphere.
If there is any restriction on this pipe run (say a stepdown to standard 3.5/4.5mm union) it wil act as a damper valve, upsetting the soft mode. And then you wouldnt need the mod first off anyway, as it wont work.
You better go all the way and move all bits from the donor car.

The Activa setup has nothing to do with suspension.
The Activa system is a self contained hydrulic adjustable anti-roll bar, by way of a single hydraulic cylinder taking place of one sides droplink bar on each axle.
It works completely independent to the suspension system, only sharing the same hydraulic pressure source.
It utilises an extra HeightCorrector working off the roll-angle of each axle thus adjusting the roll-bar cylinder to keep the car level when cornering.
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Post by addo »

Anders - we're talking about the stage before any Hydractive/Activa mods actually are implemented. EG, standard car struts and rear cylinders - as fed with the small bore steel line.

But - what I'm wanting to do, is install the large bore tubes preemptively. They would still be feeding the standard setup, so there is no demand for fluid capacity of a Hydractive system.
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Post by Mandrake »

Just to expand on what Anders has said, I would also strongly recommend against replacing the side to side piping of a standard model with the 10mm thick piping from a Hydractive model.

Why ? Because apart from the fact you would have nowhere to to run the piping to (it runs to the hydractive control block down at the corner of the radiator) if you directly connected the left and right sides with such large diameter pipe the car would lose roll axis stability, and roll like a boat.

Standard models rely on the very small diameter piping from left to right to restrict the flow rate between left and right sides - effectively the entire length of pipe (with an internal diameter of approximately 1.5mm) acts as a damping restrictor for body roll.

In Hydractive models you have a large diameter pipe which would not by itself restrict the flow significantly for body roll - but instead relies on the two damper valves in the central block to provide damping and restriction for roll movements. (In the soft mode - in the hard mode it blocks the flow completely)

Not wanting to be Mr negative, but the job of converting a standard model to Hydractive would be quite substantial as there are a lot of differences.

Not only are the strut tops different but the struts themselves are as well (different taper) the piping is obviously different, the rear cylinders and piping are different, there are the two hydractive control blocks and electrovalves which have both additional wiring and high pressure lines / low pressure overflows, there is the ECU unit and all the loom wiring going to that, there is the brake pressure sensor, the steering wheel sensor, the body movement sensor on the roll bar, the speed sensor on the gearbox, the wiring and button for the sport / normal switch, the anti-sink valves are different to the standard model, the list goes on and on...

An "incremental" conversion would not be possible, at minimum you would need to replace all at once, the front strut tops and struts, fit the large pipes that run down to the corner of the radiator, AND fit the hydractive control block and sphere so that those pipes would have something to connect to, then run a small pipe from there to the height corrector, another small pipe from there to the main high pressure distribution block, run an overflow pipe back to the resoviour, AND swap the anti-sink valve.

You would then at some point need to do the same at the back. This is all before you even worried about the electrical side of things. :roll:

Regards,
Simon
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Post by addo »

Simon, I'm surprised at you doubting me, given we share another haunt. :wink:

Anyhow - what I'd been really hoping to hear, was that Parker or someone like that made a compatible stepdown fitting, similar to the way you can get step up or step down flare fittings, flare to -AN, etc etc.

I've no intention of running other than standard cylinders or spheres until everything else is taken care of. I'd argue that the bulk of suspension work on a non-Hydractive car is undertaken by the sphere and cylinder. Given that the inlet sizes of these aren't changing, would you agree that the inherent restriction (of this system) to which you refer, is still there?

The electricals are a piece of cake by comparison. All wiring bar the underbody harness and front jumper harness, is already taken care of (and the corresponding interconnects for those two are in place). The electrical side of it really is "plug and play" - at least to HII level. Citroen really went to a bit of trouble with the X2 and it was further simplified with a bunch of multi-application harnesses for the (comparatively) small RHD market. If I hook all this up without the electrovalves it may just log fault after fault - that won't affect the car's current performance.
the car would ...roll like a boat
Being a wagon, it already does - to a degree! :lol: If I do something that renders it apparently unsafe I would immediately reverse the procedure. But honestly, the way it lurches on a locked converter 2-3 shift (as per the factory transmission software) can give you a decent fright if it happens in hard cornering on a wet road. That's as built, and I consider it potentially VERY dangerous...

Regards, Adam.
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Post by AndersDK »

No matter how or why you do it - I wont recommand you do it.

As Simon points out there is no way to connect the large piping - other than using yet another pair of odd size stepdown unions.
The large diameter piping would need to be bend and messed with, which for sure will cause the piping to collapse at some point.

I repeat : either you transfer all mating bits from the donor car - or leave it as is.
To be honest : I fear you have lots more guts than brains in this project.
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Post by addo »

You wrote:To be honest : I fear you have lots more guts than brains in this project.
It's difficult not to be offended by a remark like this, or your preceding responses, but perhaps we can put it down to translation (as I reasonably doubt you think in English)?
I wrote:If I do something that renders it apparently unsafe I would immediately reverse the procedure.
Maybe reiteration of this point, will reassure?
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Post by AndersDK »

Sorry - no offense intended.
I wont comment further on your projects.
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