Struts Leaking Rate

[jorgy9]

Hi all,

does anybody here really know what's the point where you'd say that a strut "is leaking" and should be exchanged?

I have an issue with loosing pressure quickly and I checked my rear struts return pipes yesterday -well, one of them, access was bad in the other-. So, car being in normal height, engine running, it leaks a drop every 5-10 seconds. A drop large like a lentil. Is this normal leaking or is it "bad leaking".

thanks

George

[UFO]

I have never seen a leak from a rear strut return line unless you count the right suspension boot on my DS. But then I have the added advantage that our roads do not have the entire contents of a Russian salt mine dumped on them a few times a year.

Fix the leak before it leaves you stranded or gets much worse.

[DerekW]

Hi George,

Yes, sounds too much.

I had a bad leak past the piston in one of my units some years ago. It never seemed to affect the ride though, I suppose the pump output was more than enough to keep up with the leakage. The two symptoms that I had were:
1. The back end collapsing in a couple of minutes when stopped, despite the presence of antisink.
2. When sitting stationary in traffic, looking in the rear view mirror I could see the back end falling and rising, falling and rising to the amusement of the driver behind.

Problem is, you don't know whether the leak is caused by a worn piston sealing ring or if the ring is starting to break up, so best get it sorted.

Derek

[Peter.N.]

If the strut seal really fails you will know as the pressure can be sufficient to push off the leak off pipes. Yours doesn't sound as though it is in imminent danger of failure.

Peter.N.

[jorgy9]

Thank you all Derek, UFO and Peter for your input, it's very valued as I know you are all quite experienced with Citroens.

Let me clarify that I'm not getting any other bad symptom except that my XM cannot achieve the softness it should (when it's in "soft" of course, electronics are all working fine). The pressure range the regulator provides (153-177bar) is theoretically super enough for the evalves to operate correctly. Further, my regulator clicking every 18secs, when all spheres are new and checked, and the SOURCE of pressure is checked and tuned, with gauge. I thought 18secs in this context is a bit poor.

All else works well, car rises fast, diravi works well, rear drops in 2-4 hours (no antisink) etc.

It all points to leaky electrovalves perhaps.

Derek, what was your leak rate like in the damaged strut? I guess larger than mine?

UFO, do you mean you've never actually seen a rear strut returning the slightest LHM at all?

What I'll do next is go to the LHM tank return pipes and check from there, no point lookign at every signle element's return point. According to my calculation I should see a large influx there, about 15ml/sec*. That's quite a lot, hundreds times more than the leak I saw in the strut could produce. So my guess is there's a bigger leaks somehwere else. I'll keep you posted.

George


*pressure regulator: 153 to 177 bar= 24 bar range, clicking every 18secs = 1.3bar/sec loss.
Accumulator: 55 bar static (measured), volume 400cc.

177/55=3.21 times
400/3.21=124ml when pressed at 177bar
400-124=277ml of fluid available
277/18 = 15ml/sec loss

[Peter.N.]

Have you changed the centre spheres? These are the ones that have the most effect on the ride.

Peter.N.

[jorgy9]

yes, all new, as I said anything that has to do with the source of pressure has been examined and fixed.
G

[UFO]

jorgy

I assumed from your post that you meant the lines themselves were actually leaking - as in dropping fluid on the ground. I have never seen this happen in an XM. If by leaking you mean returning excessive fluid via the LP return lines to the tank, I can honestly say I have never seen that either - probably because I have never looked for it!

[DerekW]

Hi George,

Hard to say what the leakage rate was, the rear end would collapse completely within about 5 minutes, so I would guesstimate that the rate was more than 1cc/min. If your's is staying up for hours then I wouldn't worry about that particular source.

"Diravi works well", go on, you're having a laugh aren't you? You know we're denied that particular pleasure!

Derek

[Peter.N.]

....Unless he has an early left hand drive.

Peter.N.

[DerekW]

Peter,

I got the impression - maybe incorrect - that George lived in sunnier climes than ours, maybe Spain or Portugal.

Derek

[jorgy9]

hehe...George used to live in Athens-Greece up to 2001, when he deciced to travel to Scotland to add some international flavor to his education, and here he is now on the verge of submitting his PhD thesis...

BTW, my XM is diravi-ed because I went to look for it in Germany...no relation to Germany again, just a good friend overthere who helped with registration/export issues! Mind you, I bought it on German ebay so was a bit like a lottery. Indeed, car was very nice in everything, except it had been run for -I suspect- 10k miles on flat spheres, hence my trouble with the suspension now...It had comletely flat spheres when I got it but I didn't know back then (my first hydraulic Citroen).

G