Xantia ride height adjuster unit, Rear

[jgra1]

Hi, My 1.8i 1999 Xantia has been suffering no back suspension for a few days.
I had a look underneath and the metal arm which connects rear roll bar to plastic rose joint has snapped.
I have a feeling this may be down for a stiff height corrector unit

The unit is hard to move in or out by hand, even using mole grips as levers.. I am thinking that if i struggle to change vehicle's height, a small metal rod will to..
so, I am on the right lines? and is it easy to fit one of these units? anyone know roughly how much I need to pay?
thanks
John

[Mandrake]

Hi, My 1.8i 1999 Xantia has been suffering no back suspension for a few days.
I had a look underneath and the metal arm which connects rear roll bar to plastic rose joint has snapped.
I have a feeling this may be down for a stiff height corrector unit

The bronze welded link on the rollbar clamp snapped, but the plastic link didn't ?? Wow... Did it fail at the point where its welded ? Seems more likely to be a manufacturing defect if it did, as I can't see the plastic link surviving the amount of force needed to break it.

The unit is hard to move in or out by hand, even using mole grips as levers.. I am thinking that if i struggle to change vehicle's height, a small metal rod will to..
so, I am on the right lines?

Maybe not. When a height corrector is full of oil it has internal hydraulic damping which is very strong and prevents sudden movements. It will resist any sudden movement, otherwise it would correct to every little road undulation.

Also the isolating spring means that when you travel over a bump the spring flexes when the height corrector doesnt move, thus preventing excessive force. Have you checked the spring unit moves freely ? It is a relatively strong spring but you can operate it by hand.

On the height corrector shaft, if you apply constant moderate pressure you should see the shaft move about 2mm in either direction after a few seconds of pressure.

Although I see a lot of people replacing height correctors, they very seldom ever fail, however what CAN happen is that they can get full of sludge and grit from dirty oil. The damping ports are a series of small discs with a tiny hole (something like 0.2mm from memory) which allow the oil to flow slowly from one side to the other allowing the shaft to move, if they get blocked it can make them very stiff and unresponsive. (But remember its normal for them to be somewhat stiff in the first place)

If you're a fairly handy sort its actually not difficult to strip down a height corrector, clean it with petrol and compressed air, and put it together again - about half an hours work.

To begin just prise the backing cap off, which is plastic, and remove the rubber boot off the front shaft end, and you'll see a bolt and a large washer. Just unscrew the bolt/nut and prise off the inner rubber boots as well - these will be full of oil.

Inside you'll find a circlip, a washer, a spring at each end. Once you remove them from one end you'll be able to push the shaft back and forth some distance, just give it a thorough clean with a brush and petrol and if you have a little air compressor use that through the ports as well...

Then reassemble. It should be free and easy to move now because it is empty of oil, and it will correct the height too fast for the first few hours/days until the galleys inside fill up with oil and then it will suddenly slow back down to normal speed...you can pour a little bit of fresh LHM into the unit just before sealing the inner rubber boot if you like, which will speed up that process of normalizing.

I've recently done the front height corrector on my car just like this and it turned out to be full of grit from previously dirty oil... I'll be doing the rear one soon, so I'll try to remember to take some pictures of the disassembly for people, as its really not that hard and sure saves a lot of money!

Note: if you do decide to remove the shaft completely (I didnt when I did mine) beware that the centre raised sections on the shaft that form part of the valve are finished to 10 microns, and if you scratch or abraise them it may damage the surface and cause excessive (internal) leakage in the height corrector. So don't even lie the shaft down on a workbench...

Regards,
Simon

[jgra1]

Simon, amazing reply!

I have ordered a new roll bar clamp with the metal part that broke. (It broke near where it goes into roll bar clamp, on a shoulder.
£12 from Citroen.
I will certainly have a go at dismantling height corrector/adjuster piston. nothing to loose..
I disconnected the manual height adjuster rod,(prised the spring legs apaprt at the same time) and the roll bar was already disconected, then I had long mole grips vertically on the vertical manual adjuster lever arm, so i was getting about 1' levereage... I was applying steady and firm pressure, and i could feel it 'click' as the shaft moved.. (i.e. not smooth movement) felt very much like dirt is in there...

sorry my teminology is not quite there yet, this is my first xantia and my first look at the underneath..
bloody cold out there!!

[jgra1]

Hi Simon,

I now think the spring unit is the problem..
I have oiled and wd40'd it.. i think it's getting there..

I tried to remove the 3 hydraulic pipes from the corrector unit but they showed signs of imminant failure, so decided to leave them alone.

Instead I removed just the rear of the corrector and true enough, there was some sludge in there. If nothing else, taking it apart allows it too move freely, and therefore takes it out of the equation. Anyway, i pushed and pulled the whole mech as much as possible, and I think it is free-er than it was.. if i do max/min on the manual adjuster a couple of times a week maybe I can keep it like this...
will go under tonight and try to reset height adjuster (the car still goes to max height on 'normal' setting as I dont think the roll bar is pulling corrector early enough..

will let you know
John

[JohnT]

What a good reply by Simon....can we get this in the archive please?