Advice on Xantia Sinking problem again

Karl · Post by **Karl** » 09 Dec 2003, 16:43

What are all the possible causes for a Xantia fitted with Anti-sink to sink?
I had this for a few months now and think its time to get to the bottom of this, so far I have replaced both the accum and anti sink sphere, but don`t have the knowledge to locate the source of the leak, so any advice would be appreciated. Thanks

Post by **RichardW** » 09 Dec 2003, 17:59

Karl,
The antisink works by having a valve in the line between the height corrector and the suspension cylinders. As the main system pressure decays, this valve closes and isolates the suspension cylinders from the rest of the system.
My thoughts are that if you have very rapid sinking, then your height correctors are leaking all the pressure out of the suspension system before the anti-sink valves have a chance to close and isolate the suspension. This should give rise to very high leakage rates from the height correctors during normal operation.
If the sinking is longer then there are 2 main possibilitites I think:
1. The A/S valves are not closing and allowing the pressure to decay through the HC as it would in a non-A/S car.
2. The A/S valves are closing, but the pressure is decaying via leaks in the suspension struts.
The latter should be relatively easy to diagnose by removing the front leak off hoses and tucking them in a jar instead of letting them return back to the reservoir and seeing how much fluid is returned. The former you can probably check for by removing the appropriate return hose at the reservoir and observing the reurn flow rate.
I just thought of another possibilty too - the A/S valves are leaking internally and somehow contributing to leaking the system pressure back via the PR.
Hmm, lots of causes, but not much to go on for fault finding. Anybody got any thoughts?

David Goddard · Post by **David Goddard** » 10 Dec 2003, 02:00

Is the ride height within spec. Just a thought. May be worth checking it.

Karl · Post by **Karl** » 10 Dec 2003, 02:58

Richard
Your suggestion that it might be the A/S valves not closing might be the cause, so this afternoon I went out and bought some Hydraflush and replaced the LHM. I check in the morning if it has made any difference.

Karl · Post by **Karl** » 10 Dec 2003, 14:50

I was in a rush to get to work this morning so it’s not scientific, but the car was noticeably not lower than before putting in the Hydraflush, and seem to come up immediately after starting up the car.