Strange Behaviour Of Rear Suspension.

[techmanagain]

Cx ; F Reg ; rear suspension - on one side only - is hard, despite changing sphere. Height control operates correctly, raising and lowering car as normal, but one rear side is virtually solid at all heights and check of suspension piston does not reveal any external corrosion to cause piston to stick. Another replacement sphere is on the way in case the replacement is faulty, but there may be some other problem which I cannot visualise. Anyone ever come across this before? Techman

[UFO]

Really stupid question, but there's not a rock or something preventing the wheel from rolling back and therefore that side of the car will not lower?

[techmanagain]

An interesting and original response, but the car will rise and fall correctly on a level garage floor without either the brake on, nor any block as suggested. I am thinking that I have a dud sphere but as I don't fancy the job of replacing it again, I am clutching at straws!

[techmanagain]

Replacing the sphere with one from GSF allowed the suspension to act as normal!

Faulty sphere, I hear you say, but the car failed its MOT due to hard rear suspension on rear driver's side, and one supplier's new sphere did not solve the problem. So were both spheres faulty or was there any other cause? The original sphere with which the car failed the MOT was tested on the bench and proved satisfactory, and checked out that it had only been replaced 15 months previous,

The cylinder was removed to the bench and found to have no extenal blemishes and a mirror-finish internally.

I can only suppose that there was a blockage in the pipe between the height controller and the cylinder, which was not noticed when it cleared during the dismantling. There can be no other logical solution.

Does anyone have any better idea?

[demag]

I seem to remember the rear bump rubbers are situated inside the crosstube of the rear subframe on the CX and an extension of the trailing arm fits in there to rest on them at extremes of suspension travel. There's nothing wedged in there occasionally fouling is there Techman?

[techmanagain]

Good thinking! I'll get to have a look.

[Peter.N.]

If the suspension is going up and down OK, all that's left is the sphere, however odd that sounds. Contrary to popular belief, lightning does strike twice in the same place!

Peter.N.

[techmanagain]

But the sphere, after removal, was found to be nearly fully charged. Could the valve at the end of the sphere have been blocked?

[UFO]

Seizing rear arm bearing? Does the arm move freely without any bearing type noise with the wheel removed?

[demag]

I was wondering that Craig but surely it would have been picked up on the Mot.

[Peter.N.]

You've got me thinking now... Surley in the 'normal' suspension position, the centre sphere should allow movement even if the outer one was flat. Providing nothing mechanical is seized, one side lifting will lift the other side via the anti roll bar. You havn't got a collapsed pipe somewhere? If you disconnect the pipe to the strut top, you should have fluid from the pipe when the engine is running and from the strut top when the suspension is lowered - that might point you in the right direction.

Peter.N.

[Peter.N.]

Sorry - Ignore the bit about the centre sphere - I thought I was writing in the XM section.

Peter.N.