Front suspension 'jumps' when starting

[Nitrosurf]

Hello! Sorry if this problem has been covered, but a search here and on Google/Duckduckgo hasn't heralded results...

When starting my '98 XU9 Xantia (usually when it has been sat for a few hours) the front 'jumps' up rather dramatically, with a burp-like sound. It then drops itself down a bit then raises up slowly to normal height. It does this in good time so isn't a hindrance as such but doesn't bode well methinks...The guy I bought it from said the spheres had been changed within the last twelve months, but maybe he didn't mean all of them. The accumulator sphere seems to be clicking a bit too often (not just for a minute or two) so could the problem be related to that? The car goes from full extension to down on the bump stops within a minute or so (and holds full height no problem), but does it front then back rather than all at once (this may be normal, it's my first Citroen!). I recently had a fluid return pipe break on the n/s front which I repaired and lost about 500ml of LHM as a consequence, but no other pipes seem broken. In relation to this, do I have to purchase Citroen specific pipe or can I just make up replacement sections from any hydraulic grade pipe of the right gauge?

Thanks in advance for taking the time to help.

Liam

[demag]

Hi Nitro I would definitely get the accumulator sphere replaced. It will help things. I'm not sure about Xantias but jumping front suspension on a Bx is usually down to the front struts drying out. Someone will be along soon to let you know. Is the suspension soft or hard? Put it in normal ride height and push down firmly on each corner. There should be quite a bit of travel and the movement should be soft and fluid. If there is any firmness you have a few problems, all of which can be addressed. Have you tried a Citaerobics session? Go from full low to full high suspension on tickover a minimum of twenty times, that will help to move some lhm around the system.

[Hell Razor5543]

When you replace the accumulator sphere I would suggest you also replace the anti-sink sphere at the back. It serves the same purpose as the accumulator sphere, but (other than taking it off and pressure checking it) it does not display any symptoms of it failing. As a consequence it may no longer work, but you wouldn't know this.

Something that might help with the groaning front struts is to take the car to full height, pop the gaiters off, and grease the struts with a high moly grease. Re-seat the gaiters and then do a Citrobics session. The rear struts self-lubricate (there is a designed leakage for this purpose) but the front struts do not.

[Nitrosurf]

Thanks for the advice. Having had a good look around with the air cleaner off (fitting the clutch cable) I've noticed the hydraulic piping appears to be bodged. The pipe that feeds the accumulator sphere seems to be made up from two bits of hose, with the join clamped over by three (!) jubilee clips. They seem to be gripping the hose quite tightly, so I was wondering could this bodge be starving the accumulator sphere of the correct LHM pressure? Or is the accumulator just likely to be knackered and the bodge a coincidence? I'm obviously going to have to replace the pipe work, but where do I source replacements? Can't seem to find OE flex pipe online, so maybe it's a case of just buying hydraulic pipe in the correct bore/diameter? Sorry to keep blasting questions but I've grown attached to this car, and would like to get her at least mechanically sound (the paintwork will have to wait!).

[demag]

Nitro the bodge on the accumulator feed pipe is usually an indication of a flat accumulator sphere. As the shock absorbing properties of the sphere are not there the weakest point usually fails which is the feed pipe. It happened to me many years ago in my Cx. Luckily I was just around the corner from home but left a trail of green blood along the road.

[Mandrake]

This "bodged pipe" is it a thick hose all the way to the pressure regulator ? (the unit the sphere is screwed onto)

If so this is the LOW pressure return line which returns from the pressure regulator back to the reservoir tank at the top. This pipe is subject to a reasonably high flow but never to high pressures - only just above atmospheric. If the seal seems to be tight and secure and free of any oil weeping I wouldn't worry too much about it as replacing the entire length would be difficult and probably quite expensive.

On the other hand if it is a flexible hose that is about a foot long and converts to a steel pipe before going into the pressure regulator this is the HIGH pressure supply from the pump to the pressure regulator and I WOULD be concerned about any bodgy repairs here as it is subject to 170 bars of pressure. A replacement for this pipe can be sourced from a scrapped car and fitted without too much difficulty.

As for your original complaint of the car suddenly jumping up with a funny noise then dropping back to the correct height soon after starting, I'm assuming that your car is Hydractive 2 ? (It would help to know more about your car especially spec level eg SX, Exclusive etc)

If so I'm pretty confident your problem is with the front Hydractive electrovalve. It will either be mechanically sticking or internally leaking (in which case it needs replacing) or the internal diode has failed - in this case you can perform the "diode mod" (see elsewhere on the forum) to restore normal function quite cheaply and without replacing the electrovalve.

Also definitely get your accumulator sphere replaced if the tick rate of the regulator is any faster than once every 30 seconds with the car sitting idling at a steady ride height.

Note: an internally leaky electrovalve can also cause a fast tick rate even with a good accumulator sphere, but the accumulator sphere is so important to overall functioning of the hydraulic system (and front brakes) that it should be replaced as a matter of course if its condition is unknown. If the fast tick rate still persists after replacing it you will probably have one or both electrovalves internally leaky. This is easy to diagnose should you get to this point.

[Nitrosurf]

Sorry for the delayed response! I have an SX spec '98 1.9XUD estate, non-Hydractive. I replaced the accumulator sphere the other day as per the advice on the forum and it seems to have solved all my problems suspension-wise, apart from a weeping seal on top of the LHM pump, for which I'm hoping to find a replacement. So far I've solved my very dubious fuel economy (new fuel and air filters), the loopy suspension (said accumulator sphere) and the concrete clutch pedal (knackered cable). Just the bodged blower switch (another thread I've started) to go and some TLC for the old gal and I should be right. Must say this forum has been a great resource, it seems Citroen owners are a good bunch.

[Xaccers]

We're lovely, but then so are the cars
The seals on the pump are dead easy to replace. The one that normally lets go is the large hex with the metal suspension feed pipe coming from it, takes an O ring that cost around £1 from a dealer if memory serves. There's another one under the blank large hex. These can be replaced in situe.
The torx ones rarely leak.
The other place that sometimes goes is the big O ring between the pump and it's bell end (stop giggling at the back!).

Best to stop the leaking as soon as you can as LHM nobbles alternators

[Nitrosurf]

In response to Mandrake yes, it's the large diameter flex hose, and it doesn't weep. I think you'd be right about it being expensive to replace as I can't find them anywhere, so probably a Citroen main dealer only part...and Xac, my alternator is decidedly slick looking, so you have a point...

[isisalar]

I'll second Xac's advice re the pump o rings, and the alternator, and while you're there, replacing the tank to pump feed hose is also a doddle, search out the 'ten minute mod' thread for full instructions..
If you're impressed with the suspension now, wait until you've done these easy jobs, and then you'll be astounded.
Cheers
Paul

[Xaccers]

Silicone tubing can be used for replacing the main feed and return pipes. Its cheap on eBay as turbo gauge piping. Available in various colours.
Wrap the ends in some gaffa tape to protect them from jubilee clips and make sure they are tight.