Sphere cylinder leaking

[Eddie Nuff]

My Xantia sinker has a leak from the nsr sphere cylinder. The sphere and O ring are fine and the leak is not from there.

There was a constant drip from the cylinder area but when I pulled the clip out and pulled the boot back the LHM flooded out.
These are the photo's of the cylinder










There are only two seals inside the cylinder, a black one at the top and a white one further down. Service.Citroen says there should be three!

Can anyone confirm that I'm missing a seal before I scout the country for a set?

[aerodynamica]

Hiya, good pictures there. There is a third O ring that is underneath the white nylon seal. It's unlikely to be any of these seals though and more likely to be the cylinder bore is worn.

I ran a BX for a few weeks with all of these seals missing and it did not leak. The tolerance of fit between the piston and the cylinder is 3/10th micron! the black O ring is simply to guide the leakage LHM to the leak off pipe, the push-on LHM returns.

However, is the suspension staying up for long enough or are you seeing it visibly sink down to the stops? This would indicate the leak caused by worn cylinder bore. If it's staying up for as long as a 'sinker' does but still getting lots of LHM that leaks out then I'd check the push-on leak off return pipe isn't blocked/ kniked somewhere first.

[aerodynamica]

Also, just thought it could be a tiny little split on the rubber or that the push rod isn't securely located in the groove of the rubber boot. I had a CX with a not-quite-fully-attached boot-to-pushrod fit an it oozed LHM that was meant to find its way back to the leak-off return.

Graeme

[Eddie Nuff]

However, is the suspension staying up for long enough or are you seeing it visibly sink down to the stops?

Suspension stays up when engine is running but a steady drip, drip until all the green blood is gone. Considering it's a sinker it stays up for quite a while after the engine is turned off.

Cylinder is a tight fit but slides in and out steadily. Boot and clips are new, return pipes are in good condition as far as I can see up until they go through the body.

[aerodynamica]

Hmm I'd run it, then turn off and loosen the 12mm pressure release on the regulator and watch the rear height. If it does lower down then it's definatley a cylinder failed.

I think it might be though as you shouldn't get that much leak through. Mind you if it is staying up then that would indicate the cylinders are ok. But one thing: the leaked LHM should not get into the rubber boot - only a tiny amount of LHM should be in there just to lube the push rod end.

The bigger O ring you see there is the eal against LHM getting into the rubber boot so Any large volume of LHM in the boot would suggest the O ring is either deformed and allowing LHM to syphon down from the tank (if the system is staying up and therefore not losing pressure). If it's syphoning LHM down to the boot from the tank the thing could be filling up and then rupturing at its weakest point when the suspension moves. The rubber boot is meant to be largely filled with air, that's why it has a vent tube attached to it.

[Eddie Nuff]

The last thing I want to do is put this all back together to find it's doing exactly the same thing. From watching the suspension work there seems little wrong with it - it just leaks in one place.

May be prudent to put a new O ring in it before I put it back together.

[aerodynamica]

Yes probably the best decision. Maybe the cheapest too!

[Mandrake]

Careful not to scratch that exposed piston when handling it! Even a small hairline scratch will cause it to leak more than it does now.

As Graeme says the rubber seals are only to collect the leakage return they're NOT there to seal the high pressure. It's the incredibly close interference fit between piston and cylinder that is the "seal".

[Huskyxantia]

Very interesting read , my car had same issue 2 yr ago main dealer no help, but this place helped me back on the road