Sudden LHM leak from rear

Rob_e (UK) · Post by **Rob_e (UK)** » Tue Dec 04, 2007 4:52 pm

Last night when I came out of work and started the car, after it had finished lifting up, I drove off and saw the stop light and hydraulic level/pressure light flicker on a couple of times. So I pulled in a put the suspension on high and tried to top it up. I put the whole bottle in only to find the level still hadn't raised. When I went round to put the empty bottle back in the boot I found a rather large puddle of LHM under the left hand rear suspension unit, Pretty much the whole litre I had just put in I imagine. Once down to normal drive height it made it home (over 30 miles drive) without too much more fluid being lost, although there is a constant but much slower flow, I guess the extra pressure of being on the high setting pumped it out a lot quicker.
Unfortunately this time of year it is dark when I get home in the evenings so it is difficult to get a good look at it.
So my question is, is there a common problem most likely to cause this leak? I think the leak had been quite slow until now as I havn't seen puddles of LHM under the car until yesterday. I did think it might be the pipe supplying the cylinder had burst as on high the flow was quite quick; but it is able to pressurise the rear suspension enough to lift the back of the car and I would have expected a hole in the pipe to stop the pressure builting up enough for that, and I would expect even a normal drive height the leakage rate to be a lot higher. Do sphere seals go? I have only ever replaced them when changing sphere and have never had any leaks before from the rear.
I know when front struts have had their internal seal go they blow of the return pipes and spill loads of LHM, do rear cylinders go the same way? I think the leak is coming from the upper (sphere) end of the cylinder, although it is hard to tell in the dark.
Any suggestions greatfully received.
Thanks,
Rob

Brian · Post by **Brian** » Tue Dec 04, 2007 5:03 pm

Hi Rob,

Two possibilities come to mind:

1. Corroded high pressure pipe feed to the cylinder.
2. Corroded cylinder.

Not easy to locate in the dark, good luck.

jeremy · Post by **jeremy** » Tue Dec 04, 2007 6:54 pm

Its not a cylinder as the car achieved the correct height and stayed there.

Its not a high pressure pipe as the car achieved its correct height.

My guess is that its a return pipe - car sinks and the LHM is just dumped - start car and it pumps 2 rear cylinders full of LHM into the back suspension quite correctly - but the reservoir level drops.

<ay even be the return from the height corrector which I think has a rubber bit at the corrector end.

ken newbold · Post by **ken newbold** » Tue Dec 04, 2007 8:48 pm

Mmm, for my money, this is a corroded cylinder, they go at a point along the cylinder just above normal running. So when you put on high the weak spot is in play, so to speak.

Sorry but I think you're lookin at a new or replacement cylinder, and the worse news is, the other side won't be far behind. They've probably both done the same mileage, or sat in the wet crap for the same length of time.

Rob_e (UK) · Post by **Rob_e (UK)** » Tue Dec 04, 2007 11:41 pm

Well, I have had a look underneath the car this evening. It is still not that easy to see exactly where the fluid is actually coming out. The supply pipe seems to be dry as is the lower half of the cylinder around the gaiter and the vent pipes.

The fluid seems to build up in the bit holding the cylinder and then overflow and spill on the floor. It doesn't look like it is coming from the joint between sphere and cylinder so I guess it must be the cylinder that is leaking?

From the pictures does this look like what you would expect from a corroded cylinder? I am suprised it could corrode all the way through really as I always thought the struts were reasonably heavey gauge steel.
Is the corrosion normally quite localised or does quite a large area corrode through.

I did originally think that if the cylinder was leaking it would prevent the pressure building up enough to lift the car. But if the hole is just above the normal running height then that would explain why it leaks far faster oon high becuase of teh position of the piston rather than the difference in pressure.

Luckily the other rear cylinder was replaced five years ago so hopefully would not be following quite so closely behind as this one is the original (18 years old).

Thanks,
Rob

ellevie · Post by **ellevie** » Wed Dec 05, 2007 12:32 am

You're certainly not the first one this has happened to Rob. Have a look at these previous threads,
http://www.bxclub.co.uk/forum/viewtopic.php?t=303
http://www.bxclub.co.uk/forum/viewtopic.php?t=438
http://www.bxclub.co.uk/forum/viewtopic.php?t=2366

I suppose one lesson to be learned here is not to put the suspension on high when topping up with LHM in a rear leak emergency,

jeremy · Post by **jeremy** » Wed Dec 05, 2007 8:50 am

Yep - looks like the cylinder - alloy has corroded through I suppose.

Rob_e (UK) · Post by **Rob_e (UK)** » Wed Dec 05, 2007 1:49 pm

Looks like i'll need to order a new cylinder then as I need to get it back on the road as soon as possible.

when I first topped it up I has no idea where the leak was, I assumed it as slow leak so was going to try and top it up to the correct level. Next time I will remember just to put in enought to get the lguht out and wait until I get home to put in on high and fill it up properly

Judging from those other threads it looks like it may not be a very easy job.

Thanks,
Rob

mnde · Post by **mnde** » Wed Dec 05, 2007 2:56 pm

I had a rear cylinder failure on my GSA. The gaiter split and the LHM rapidly emptied onto the ground. It's not fun getting that "sinking feeling" when in traffic.

I made the mistake of crawling into an autofactor's yard and buying new LHM. It just pissed out in double quick time. If only I'd known (as I found afterwards) that raising the car to medium or high height would stop the leak!! It seems that in normal height, the fluid was gushing out past the piston, but in intermediate or high the leakage stopped - so rather different to Rob's fault!

In the end I was able to drive the car all the way from Woking, Surrey to Chevronics in Bedfordshire in intermediate height with little or no fluid being lost!

Did I read somewhere that Xantia rear cylinders are more readily available and can be made to fit?

Good luck!

Mark.

Rob_e (UK) · Post by **Rob_e (UK)** » Wed Dec 05, 2007 5:31 pm

I have just phoned both Pleiades and GSF and neither have any rear cylinders, Although GSF still have them on their website they said they are in the process of being deleted.

Anyone know of any other suppliers that may have one.

If I try to get one from a scrap yard I don't know how good the seals would be or even how long it would be before it went the same way as mine, and also I have had front struts from a scrap yard before shortly after I got the car and it caused me loads of problems with dirt in the system.

Anyone got any more info on how much work is involved in making a Xantia one fit. With a bit of luck GSF may keep stocking those for a bit longer.

I hoping to get the part asap so I could fix the car over the weekend.

Before I had found out that is was alloy rather than steel I had considered if it might be possible to fill in the hole with a mig welder, but I guess that is unlikely to work if it is alloy.

Thanks,
Rob

ellevie · Post by **ellevie** » Wed Dec 05, 2007 6:25 pm

620545645 REAR SUSPENSION CYL BX SALOON .
REAR STRUT £61.70
http://www.eurocarparts.com/

DLM · Post by **DLM** » Wed Dec 05, 2007 6:40 pm

I've got several used rear hatchback cylinders from scrappers - can't vouch for the seals but sure I could oblige with something of use to you.

Be aware that the cylinder boot clip will probably self-destruct when you come to remove it: though new boots are available the clips seem to be a bit more hard to find and a bit of fabrication may be needed to produce an equivalent.

Rob_e (UK) · Post by **Rob_e (UK)** » Wed Dec 05, 2007 9:54 pm

Well the Eurocarparts website says they are available, so fingers crossed they will really have one in stock. Cheaper than GSF's price was as well even if they had actually got them

I noticed while I was looking at the cylinder leak that the rear height corrector had weaped a small amount of fluid, so perhaps I should order one of those as well before they are discontinued; not a cheap item to get though if the other one is still actually working.

DLM, Thanks if I can't get a new one I may need to take you up on that offer.

One question though, you mention the cylinder boot clip; if I get a new cylinder do I need to swap the old boot over? Doesn't a new cylinder come with a boot already on it?

It is certainly getting harder to get parts for the BX now days with suppliers all discontinuing everything. Given that GSF have sold all the stock of cylinders they had there is obviously still a demand to why stop supplying them?

Thanks,
Rob

Rob_e (UK) · Post by **Rob_e (UK)** » Thu Dec 06, 2007 1:25 pm

I phoned Eurocarparts this morning and they did have them in stock so fingers crossed it will arrive for the weekend. Unfortunately replacement pipes are out of stock and GSF (surprise surprise) don't have them either. So I have go to hope I manage to remove the old one without breaking it.

Thanks,
Rob

DLM · Post by **DLM** » Thu Dec 06, 2007 4:24 pm

I'd get going with a wire brush and then loosening juice on that pipe union ASAP! It's a tricky area to work in but your main problem will come in cracking the pipe end union. Once that's moving, you may find that a 1/4" 8mm socket with a cut sliced through the side can be finger-spun to help extract the union. I have a variety of 8mm bits and pieces side-cut to allow them to be placed them over the pipe(including an 8mm pipe wrench - very useful tool in these circumstances) . Though they can't really be used for the cracking, they can be very useful afterwards in confined spaces

I'm pretty sure that the cylinder comes without the boot, if it's a genuine Citroen part - and the two things do have separate part numbers. Boots normally don't represent a problem though they do sometimes perish around the bases of the projections for lhm drain and air pressure equalisation. This really only becomes serious at MOT time, if a worn set of seals is letting a goodly amount of lhm past the internal seals.

When I was talking about the clip self-destructing, what I really meant was the bolt-head screw that tightens the clip up: I've mangled more of these than I'd care to admit in the course of removing the cylinders I have.

The clip itself normally remains serviceable even if rusty. If you save both the guides that the screw/bolt runs through, then it's perfectly feasible to make up another one, not forgetting to grind down the end of your replacement screw/bolt so that it fits into the guide. The guides ensure that the clip doesn't distort once on, and that the lhm drain remains open.