Removing and refitting spheres???

talbotsteve · Post by **talbotsteve** » Sat Apr 04, 2009 6:40 pm

Have done a search but most responses don't actually show/list what you need to do..... I need to replace my front spheres on the TZD sharpish as its just way too bouncy!!! my old TZD only had spheres replaced about 6 months before coming off the road, my question is is can you use old spheres or does gas escape when they are removed?? (don't really know how they work to be honest).
If whilst removing does LHM fluid escape from the mount?? Is it a messy job? and can you use a ratchet strap for an oil filter to remove them??

Could be a good thing for a sticky technical guide???

Cheers Steve

rob-81 · Post by **rob-81** » Sat Apr 04, 2009 7:31 pm

http://www.bxclub.co.uk/diy/

Try this....

talbotsteve · Post by **talbotsteve** » Sat Apr 04, 2009 7:39 pm

OOOOO excellent thanks very much......

DLM · Post by **DLM** » Sat Apr 04, 2009 8:10 pm

my old TZD only had spheres replaced about 6 months before coming off the road, my question is is can you use old spheres or does gas escape when they are removed?? (don't really know how they work to be honest).

You'll find a lot of useful stuff on the Hungarian BX DIY site (in English) - I'd recommend a visit. Google "BX DIY" to locate it. That'll give a good idea of how the spheres work, if I remember correctly, as well as a lot more. Sphere removal & replacement procedure is covered there.

If the spheres were only on the old car for 6 months, and the old car hasn't been standing too long, then it should be OK to re-use them. Spheres do have a shelf-life, and a limited life on-car, but only lose pressure very gradually. Some seem to hold pressure better than others.

Good thing they're front spheres you're changing, as these are easier to remove - and also can often be removed from a "resting" BX even if there's no suspension pressure available for the sphere "cracking"procedure . Not so with the rear spheres, but I won't go into that.

No gas normally escapes on removal : the Nitrogen is held within a section of the sphere within a rubber diaphragm. Usually that gas only ever escapes violently if the spheres have been left on the car too long, and the diaphragm ruptured because it's been abraded against the body of the sphere.

If whilst removing does LHM fluid escape from the mount?? Is it a messy job?

A little LHM escapes, but only only in large quantities if the sphere diaphragm has ruptured, or if you don't release the system hydraulic pressure completely before the final stage of sphere removal - which would be dangerous in any case..

If you fear it might be messy - and I'd recommend this for the hard cspheres coming off your current car - put a plastic bag around the sphere after "cracking" it (see BX DIY site for an explanation of this term). Keep this in position around the sphere while you unscrew it by hand. I wouldn't wear your Sunday best, though, and keep a rag around to mop up any minor spillage and wipe your hands.

and can you use a ratchet strap for an oil filter to remove them??

If it's a sturdy chain type, probably yes. Again, it's covered on the BX DIY site.

Could be a good thing for a sticky technical guide???

The procedure documented in several places on the net - The BX DIY site is just one of many as there have been spheres fitted to hydropnematic Citroens for over 50 years so websites for several such models cover the general procedure.

talbotsteve · Post by **talbotsteve** » Sat Apr 04, 2009 8:14 pm

Excellent cheers fellas.......

RxBX · Post by **RxBX** » Sat Apr 04, 2009 8:27 pm

Steve ,
Link to a show you a 'typical' Cross section thro' a Sphere plus a lot more !

http://www.mars.dti.ne.jp/~ynar/bxorg_a ... /t03e.html
Enjoy !

RxBX · Post by **RxBX** » Sat Apr 04, 2009 10:50 pm

DLM wrote:Good thing they're front spheres you're changing, as these are easier to remove - and also can often be removed from a "resting" BX even if there's no suspension pressure available for the sphere "cracking"procedure . Not so with the rear spheres, but I won't go into that.

The rear spheres can be fairly easy to change (If luck is on your side) but there are a few EXTRA things you need to be aware of prior to attempting that task as you can easy damage the cylinder feed pipes and retaining plate

I always have the engine running so as to keep the pressure on between the cylinders/sub-frame this helps to prevent the cylinder rotating.
I then just 'crack' the thread on the sphere slightly and shut the engine off, then depressurize the hydraulic system prior to the final sphere removal.
This is so as NOT to crack/break the feed pipe, but this does not always work and you do end up having to replace a pipe on the odd occasion, so BEWARE !
SAFETY NOTE

Always support your Citroen

with Axle stands when working underneath it if you want to stay alive !

talbotsteve · Post by **talbotsteve** » Mon Apr 06, 2009 5:03 pm

Changed them over this afternoon now car drives like a dream, dead easy to do aswell, both spheres on my old estate and the defective spheres on my newer one broke easily and were swapped over in 5 minutes.....

DLM · Post by **DLM** » Mon Apr 06, 2009 6:50 pm

.....which is the point where you begin to wonder why some people who only just know that such things as Citroen spheres exist and have no idea what they look like - make such a fuss about them. ("It's a hand grenade, mate - call the bomb disposal squad! ")

Job jobbed - congratulations.

Then of course to spoil it all you end up doing a set of character-forming rear spheres that a previous owner left on there for too long some day.

As rxBX says, rear spheres do need to be under pressure when "cracking" to prevent rotation and pipe damage. There's only one way to ensure this - the car must be both "up" on the suspension in high AND with stands ready in place for any drop but not yet taking the weight of the car.

When you do that very similar job, only from "down under", serious tools are the order of the day and a sphere removal tool really comes into its own. You're probably seen details of that now on BX DIY. My local Citroen-trained mechanic uses a big Facom chain-wrench with a handle.

Handles? You quite possibly need help from an extension bar too. Superheavy loads in the boot and big stilsons for cylinder-gripping may also come into play for really reluctant ones and cylinders that rotate despite best efforts.

Apologies for the minor nitpicking.

tom · Post by **tom** » Mon Apr 06, 2009 7:40 pm

The only simple way with rear spheres is the old hammer and bolster chisel route. A sharp whack on the periphery always does the trick.
Those who wince at this approach need to know that a hammer is an engineering tool as well. An engineer knows where to hit it and how hard.
(My smallest hammer weighs 25Grammes.) It is used in watchmaking where you hit bits exactly and gently, because some of them cost more than Whole BXs!)

Way2go · Post by **Way2go** » Mon Apr 06, 2009 8:01 pm

I use that technique for the accumulator sphere and it works well. For the rear spheres though there's more room to move and a good strapwrench on a 2ft breaker bar has always worked for me. These are both tools that are useful elsewhere on the car too unlike the specialised sphere removal tool.
(Incidentally the Halfords 1/2 inch drive chain wrenches will break easily on this job and with less leverage than the 2ft breaker exerts.)