Air in Xantia suspension - help please!

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stratty
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Air in Xantia suspension - help please!

Post by stratty »

Hi
I've got a '99 Xantia 2.0 Hdi (110) on 53k miles. Late last year the power steering went very heavy, shortly after all 4 spheres were changed. After checking the steering components, I eventually noticed that the LHM was black, after only 10k miles since the last change. I think that the local garage who service it accidently put a lower grade LHM in than the recommended LHM+.[:(!]
We changed the LHM & cleaned the filter/reservoir no probs, but found air in the system when bleading from the 12mm nut close to the accumulator. I know everybody says this, but what a difference new spheres and a LHM change makes![:)]
The steering was fine immediately after that and has been until this week, when it totally locked up a day after a 300 mile run. I bled the system again, (low suspension, engine off, after a good run)and again found air. The steering was fine again!
Q - does anybody know where air could be getting in?
Any help appreciated!
Cheers
dan.2cv
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Post by dan.2cv »

I have heard that the main suction hose can become perforated and suck air along with the LHM
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AndersDK
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Post by AndersDK »

What's that air you're talking about ?
The 12mm bolt on the regulator is definately NOT an air bleed screw.
It is a PRESSURE RELIEF valve used for service tasks only - like taking off the system pressure for replacing a sphere or broken line.
The system with pump, regulator and accumulator sphere is very effectively self-bleeding - by the way it is constructed.
If you hear a hissing sound when you loosen the 12mm bolt - it is the noise from accumulated LHM under high system pressure escaping to the reservoir - definately NOT air.
The only way air can get into the system - is by a leaking feed hose to the pump. This hose is on the pump's suction side and therefore under vacuum. Leaks are not seen then as LHM can not escape (under vacuum) instead air is sucked in.
During the service life of the spheres - the spheres leaks out very slowly their precharged N-gas into the high pressure side of the suspension system. This is also known as "air" and is mostly effectively vented to the reservoir. But sometimes may stay in the system. This is vented by the wellknown Citaerobics
stratty
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Post by stratty »

Anders and Dan
Thanks for your help.
Ive checked the feed host to the pump and all seems OK - in the dark and wet. Will look in more detail when the weather is better....
The 'citaerobics' caused the neighbours curtains to twitch! There are 2 new C5's in the road, but I might have the last laugh when their electronics go pear shaped.
I'll post progress over the next few weeks.
dnsey
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Post by dnsey »

It's possible that one of your spheres is faulty, and is leaking nitogen into the system fairly rapidly. It does happen occasionally, and can be diagnosed by releasing the system pressure (with the suspension lowered) and releasing each shere in turn. A faulty sphere will spray LHM 'foam' fairly violently from its union.
stratty
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Post by stratty »

A few weeks later and the problem has gone. I have to say that I did not tighten the blead screw enough and that might have caused a few problems. After tightening it (not overdoing it), doing a few ups 'n down and moving the steering lock to lock on wet grass, everything seems normal again.
Cheers for the help - will look in again.
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