A curious thing........................

[KennyW]

Hi All,

While removing the rear suspension return pipe front to back rear HC to Octopus tubing at LHM tank, I found the following:

When I removed the pipe end from HC there was thin metal wire with the return pipe,obviously reducing the internal diameter but for what reason.

Kenny

[electronmirror]

Snap !

They say there is no such thing as coincidence. Last year I bought a rear height corrector, in its cradle, from eBay. When I removed the crudely severed pipes prior to cleaning it up I found a 2" length of 20SWG wire inside the return pipe.

'Curiouser and curiouser' said Alice....and 2 people on FCF

[CitroJim]

Yep, they all have that

The belief, whilst not being 100% sure, is that it's a damper and flow restrictor to prevent the return piping being swamped with high-pressure LHM during rapid height changes and potentially blowing plastic joints apart downstream of the metal pipe.

It might also damp and slow down what might be otherwise very rapid changes of height.

All I do know for sure is that wire is incredibly hard.

[Mandrake]

Yes, I seem to remember that my previous Xantia had that wire inside the return pipe from the rear height corrector when I had the height corrector off. I tried to pull it out (it was actually sticking out of the pipe slightly) but it was too tightly wedged in around the bends in the pipe to let go. (I got the impression it was quite long, maybe a foot or more)

Personally I would remove it if possible - if it's there to slow down the decent of the rear suspension when the height corrector makes a downwards adjustment its a very ill-conceived "tweak".

When you accelerate hard for a number of seconds in a row from stationary (especially on a V6 ) it compresses the rear suspension down hard so the height corrector open and starts pumping more oil into the suspension in an attempt to compensate. Because there is no "mystery wire" in the inlet feed pipe (only in the return pipe) the suspension lifts quite quickly.

When you then ease off the acceleration the rear suspension then jumps up and hits the top bump stops, which is quite an unsettling/unsafe condition especially if you're cornering on a bumpy road. Because of this "mystery wire" it then takes a very long time (10-15 seconds) for the height to drop back to normal. Without the wire it might have only taken 3-4 seconds, which would have been much more acceptable.

If anything that wire should have gone into the inlet side to slow down lifting to minimise squat correction, not the outlet to slow down decent...

If I ever have the rear height corrector off this car I'll be yanking that wire out if at all possible...it definitely wasn't there in the early sinker non-hydractive Xantia's which could rise AND fall very quickly (and without problems) so I'm not sure if it was introduced with anti-sink, or whether it's only in Hydractive 2 - I have a vague recollection that my Dad's 1994 anti-sink but non-hydractive Xantia did not have this "slow fall" behaviour, so it might be a Hydractive 2 only thing.

[KennyW]

I cut the pipe into sections when I was removing same and pulled it out with pliers it is several inches long.

Kenny

[ACTIVE8]

So is this wire fitted to an Activa as well?

Or would it follow that it was not present in the series one Activa, and is in the series two?

[CitroJim]

So is this wire fitted to an Activa as well?

Definitely in the S1 Activa as I has to do some re-piping around my rear height corrector a couple if years ago and discovered it then...

It's not there now but has made no difference so far as I can tell...

[addo]

What if it were spring steel, intended to keep the polymer pipe from deforming under the "relaxing" flow of hot LHM?

[Mandrake]

Polymer ? Its in the high flow steel return line from the height corrector, not the rubber leakage return.

[Mandrake]

So is this wire fitted to an Activa as well?

Definitely in the S1 Activa as I has to do some re-piping around my rear height corrector a couple if years ago and discovered it then...

It's not there now but has made no difference so far as I can tell...

Does the rear not fall more quickly when making a downwards correction ? The Hydractive 2 Xantia's fall really slowly at the rear when trying to correct down, and I can't see anything else that might cause such a restriction...