Xantia II; knowing whether it's necessary to flush LHM

rmunns · Post by **rmunns** » 30 Mar 2010, 22:29

How do you know whether it's necesary to clean, flush and replace LHM throughout the system?

Mine (Sept 2000 Hdi90 Forte saloon) has done 50000 miles, one owner main dealer service history to 36000. Dunno if LHM was ever drained and replaced.

Colour of fluid in the tank is pretty bright, clear, fluorescent green. No losses since I've owned it (9 months0.

The suspension is a little lumpy. I don't know how best to check whether it's up to spec.

I suspect the acc. sphere might need replacing. Can't check on the frequency of ticks because the engine noise.

Xaccers · Post by **Xaccers** » 30 Mar 2010, 22:38

If memory serves, LHM should be replaced every 36K with hydroflush used every 72K

Post by **CitroJim** » 30 Mar 2010, 22:46

Citroen recommend the LHM is changed at 36000 mile intervals or every three years.

LHM does deteriorate so to be on the safe side, I'd drain it, use Hydraflush for a thousand miles or so and pop some nice fresh LHM in. I find LHM can look nice, clean and bright at first glance but when looked at in a jamjar can be quite yellow and mucky. Clean the filters in the LHM reservoir as well.

The health of the accumulator can be judged fairly well by doing a "sit in the boot test".

Switch off the engine and then open the tailgate. Sit on the boot sill and feel the suspension sink down. If the accumulator is OK it'll have sufficient reserve to bring the height back up to normal after 20 seconds or so. Get up and see the rear rise high and then fall back after 20 seconds or so. If it stays high (because the anti-sink valve has closed due to falling system pressure) the accumulator is marginal. If the rear levels out again the accumulator is good. If the accumulator (and hydraulics generally) is really in excellent fettle it'll allow another half-round of corrections before it is exhausted.

If the rear goes down and stays down on the first test, the accumulator is tired.

It's a good idea to check the rear behaves correctly as above with the engine running to ensure another fault (such as a sticky height corrector mechanism) is not present and confusing matters.

A good system will be seen to demonstrate this correction behaviour whenever rear passengers alight soon after stopping the engine.

rmunns · Post by **rmunns** » 30 Mar 2010, 22:47

Maybe if I contact the main dealer who serviced the car then they can tell me whether they ever changed the fluid?

rmunns · Post by **rmunns** » 30 Mar 2010, 23:21

Thx for good replies, second one was posted as I was writing my query about main dealer records.

addo · Post by **addo** » 31 Mar 2010, 00:03

My two bob's worth about DIY Hydraurinçage substitutes...

All of the leaking/split hoses I experienced, followed not long after running 25% diesel in the hydraulics upon recommendation of a fellow club member. An acquaintance experienced near-identical failures after similar process.

We both did this, because the "real deal" is unavailable here. Based on my own experiences (and wallet pains) I wouldn't recommend substitutes!

Regards, Adam.

Xaccers · Post by **Xaccers** » 31 Mar 2010, 00:14

rmunns wrote:Maybe if I contact the main dealer who serviced the car then they can tell me whether they ever changed the fluid?

They probably wouldn't know, and most likely didn't change it.

ACTIVE8 · Post by **ACTIVE8** » 31 Mar 2010, 15:35

Xac wrote:
rmunns wrote:Maybe if I contact the main dealer who serviced the car then they can tell me whether they ever changed the fluid?
They probably wouldn't know, and most likely didn't change it.

I agree with Xac, and also whatever records the main stealer keeps get cleared off their I.T. systems after a certain period of time, they then keep a paper archive, up to about five years approx as they are required to, then the paperwork gets binned.

Old-Guy · Post by **Old-Guy** » 31 Mar 2010, 16:41

I agree with Xac and Activa. Based on my own experience, I would say that it's highly unlikely that a main dealer would have ever changed the LHM - regardless of what the service schedules say or what has been billed.

After 11 years of (documented) main dealer servicing, when I bought my (sorry, our) S1 Xantia with 67,000 miles on the clock, it was still on 4 of the original tyres, the original cam and auxiliary belts, original thermostat, and the LHM had never been changed. The hydraulic filters were fairly clean so maybe they had been cleaned once or twice. Oil, filters and coolant all appeared to have been changed as per schedule.

The fluid that came out of the rear brake bleed nipples was a murky straw colour, but the LHM in the reservoir was bright green - perhaps because a weep from the HP pump loses about ½L per year. But of course the brake lines are dead-ends.

Xaccers · Post by **Xaccers** » 31 Mar 2010, 17:58

That's a very good point old guy, the best way to check lhm condition is bleed the brakes as its the oldest in the system

rmunns · Post by **rmunns** » 31 Mar 2010, 20:15

I have to replace front disc/pads soon (and have a look at the rear) and in view of what's been said, I think I will flush and replace LHM+ . I won't hydraflush.

Thanks again for replies.

Clogzz · Post by **Clogzz** » 01 Apr 2010, 15:08

Had the Xantia for 12 years and got to 206,000 km with it, and never used rinse in the LHM.
Replaced the LHM every two years, and the first clean of the tank turned up metal scraps, probably from manufacture.
The next tank clean didn’t show anything, so that was the last one.
The filters had some black specks the first time only, so that was the last filter clean too.

Dommo · Post by **Dommo** » 01 Apr 2010, 15:41

How do you guys replace the Hydraflush with LHM? Or is it the norm to have some left in the system, as I can't imagine it being very easy to totally drain the system of hydraflush?

Xaccers · Post by **Xaccers** » 01 Apr 2010, 16:03

Dommo wrote:How do you guys replace the Hydraflush with LHM? Or is it the norm to have some left in the system, as I can't imagine it being very easy to totally drain the system of hydraflush?

Same way as you drain it of LHM, so yes a tiny amount will still be in the pipes (except brake pipes) when you've finished.

Dommo · Post by **Dommo** » 01 Apr 2010, 16:17

I've never drained the LHM either actually

(I have read the thread written by Jim about it though by the way)

Do you want hydraflush to get into the braking system? I'd imagine you do?