Help - Search - Members - Calendar
Full Version Removing Spheres

Club XM Forum > XM General Issues
Peter N
I have just done a 5 minute job on my recently acquired 2.1 TD estate which took all morning. The hydraulic pump was rapidly cycling off and on, ah accumulator sphere I thought, I even had one in stock. I have a heavy duty strap wrench made from a section of motorcycle chain which is driven by a 22mm socket and long bar is usually very succesful, not this time, I managed to snap a 1/2" extension bar!. I eventually had to take the regulator off, put it in the vice and take a large hammer and chisel to it. Does anyone know of a less draconion method of removal?

Peter N.
I know its cheating, but when i had this with some rusted on rears I called an indy and asked him for a quote just labour only. Plenty of bull excrement saying I had no time etc etc.

Fixed price quote of £20 or £30 and it was all done.

I had been using a strap wrench made to remove filters and stuff off Unimog tractors, mean bit of kit but only managed to start moving all the housings.


I bought a sphere removal tool from Plaeides about 15 years ago and it's never let me down.

It does have two slight drawbacks though.

It is solid steel with no 'strap'. This means it has no flexibility so the handle sticks out at right angles to the sphere. This is fine if you've got room to swing the handle but this isn't always the case. The good side is though that you can lay into the handle with a mash hammer without the tool breaking. You're more likely to snap the holding down bolts of the piece that the sphere screws into.

The one I have was made at the time to grip the large spheres used on CX's and the like. The modern spheres are slightly smaller in diameter. I just use a piece of folded aluminium plate as a packer to allow the tool to get a grip.

I tried to remove my rear hydractive sphere recently to check the pressure. I laid into the handle with my mash to no avail although I did notice that every time the hammer hit the tool the sphere would move slightly but then rebound. The mounting braket for the electrovalve was flexible enough to absorb the hammer blows. So instead I applied a constant pressure from my foot whilst holding onto the tow bar and the sphere came loose.

The greatest friction which holds the sphere on tight is caused at the interface between the flat shoulder at the bottom of the sphere and the mating surface on the strut/electrovalve. In the case of the strut this is an aluminium/steel interface and in the case of the electrovalve it is a steel/steel interface. The 'grip' just comes from the surface film corrosion at this point. It is neither the pressure nor the thread which causes the friction. As soon as the corrosion layer has been broken you can undo the sphere by hand. When replacing a sphere always clean up the mating surfaces and add a smear of grease. Only hand tighten the replacement sphere otherwise you'll have the same problem next time. When you tighten the sphere you are not compressing the o-ring. The depth of the o-ring seat is slightly more than the thickness of the o-ring. It is only the fluid pressure itself which causes the o-ring to expand in it's slot and seal against the outer surface. Overtightening the sphere will have no effect on the ability of the seal to stop any leaks. For the struts especially the top edge corrodes due to the presence of salt, water and disimilar metals and becomes pitted. After a while the seal becomes exposed and can't do it's job properly.

I was asked recently to measure the residual pressure in some C5 sphere's. No problem I thought. I lifted the plastic shroud and was greeted by a squashed sphere. It looked as if it was about 20-30% bigger in diameter and 20-30% smaller in length than a 'normal' sphere and it was silver to boot. Instead of the normal filler plug there was a pimple on the end. I haven't a clue how they're filled from new never mind refilled. Does anyone know anything about these sphere's? We need a cutaway diagram to figure out what's going on.


noz cool.gif
Peter N
I have got to change the centre spheres on mine, thanks for the encouragement Noz!

I can vouch for the excellence of the Pleiades remover Noz describes - and GSF sell a similar one for rather less money! Like Noz, I have the slightly larger one that fits the 500cc spheres of the CX which has trouble gripping the 400cc spheres of our Xantia and XM. My solution is to use a short bit of hacksaw blade between tool and sphere to get the necessary grip.
One other tip, from an indy many years ago: make up a copper or brass drift (my preference) to bash the joint between sphere and strut on both sides before you start trying to loosen the sphere. It works, by breaking the corrosion between sphere and strut. And make sure the pressure is on high for that first 10 degrees of turn.
If all else has failed I have allways managed to remove them eventually by applying a sharp cold chisel to the welded seam around the centre of the sphere but this doesn't seem to be among the reccommended procedures.

Peter - yup that works too, but it ruins the sphere you are taking off. I would not like to re-pressurise such a sphere, and I have heard of one case of such a method exploding the sphere on take off. Not good news. The drift method is less brutal and has a 99% chance of success: I made my copper drift out of 22mm. copper pipe hammered flat at one end; my brass drift is a piece of scrap bar from a local foundry about 9" x 1" x 1/2". Works a treat.
Centre spheres came off like a dream! Why recharge them when you can get new ones from GSF for £18:00 + Vat?

I have in my garage 6 pieces of C-5 mushroom-shaped grey spheres at home, but still haven't got the time to cut one in half to see what is the thing that caused the famous "clonking" spund in them, which was a reason for the "noisy rear suspension" issue on the early C-5s.

Actually Citroen made a recall recently for all C-5s to replace free of charge the noisy rear spheres, with a new improved membrane design. This recall made possible to have dozens of such rear C-5 spheres available if you have friend who works in a Citroen service...

I tried two of these spheres on the rear end of my racecar BX, and there was a difference, but I will test them more when we go on the racetrack again in March.

Btw. we measured all 6 pieces (randomly taken from a big "basket" full of C-5 rear spheres after the big recall) and they were all within 0.5-1 bar from the factory prescribed pressure !! (after 2-3 years of operation) - which indeed proves that the C-5 spheres are designed for life, i.e. they should not need replacement (that is what the factory suggests at least).

Another interesting thing - the hole (orifice) in the damper part of the sphere, is not visible as in the Green spheres, but is covered by a strange piece of wire and is slightly recessed inside - so one cannot easily judge the diameter of the orifice
(anyway it seems to be in the region of the XM rear spheres, i.e. appr. 0.5-0.6mm, on first sight.

I will let you know soon, when time allows, what is the outcome of the surgery operation on such a sphere, hopefully I will upload some photographs too...


This is a "lo-fi" version of our main content. To view the full version with more information, formatting and images, please click here .
Invision Power Board © 2001-2022 Invision Power Services, Inc.
Adapted by Shaun Harrison
Translated and modified by Fantome et David, Lafter