Spheres

mezuk04 · Unread post by **mezuk04** » 22 Jan 2006, 13:52

Well went to have a quick look at a Xantia just purely to pass 5 mins of my spare time

it was £1300 for an N-Reg with about 70k on the clock, automatic in SX trim, i decided to bounce the ends to compare to my Xantia as i dont really know how good my suspension is on mine for a comparision, I was shocked to find that the front especially was really floaty/bouncy...much like Jelly

and shocked that mine is nothing in comparison so ive just bought two front spheres from GSF (jus under £50 in total) and have been searching for 'replacing' these spheres which i know has been covered many times but cant find anything that i can say for certain that it can be done to my car in the same sequence....

Does anyone have a link/copy paste sequence as i want to make sure i have the correct one for my car

JohnT · Unread post by **JohnT** » 22 Jan 2006, 15:39

Go to the search feature button, there is a whole lot of info on this.

Homer · Unread post by **Homer** » 23 Jan 2006, 07:51

Fronts are straightforward.

Lower suspension, depressurise, unscrew, fit new ones.

They should only be put on hand tight but you will need some sort of tool to loosen the old ones.

mezuk04 · Unread post by **mezuk04** » 23 Jan 2006, 08:00

depressurise in the form of that little screw (only half a turn so you dont lose the ball - see i am learning 8) )

A tool....Hmm....Is a big file and hammer ok to create the force for it to vibrate lose a little before applying the arm muscle which i have none

AndersDK · Unread post by **AndersDK** » 23 Jan 2006, 12:12

Homer wrote:Fronts are straightforward.

Lower suspension, depressurise, unscrew, fit new ones.

They should only be put on hand tight but you will need some sort of tool to loosen the old ones.

NEVER - tighten the sphers more than by handforce.

A proper removal tool is necessary to crack the (incredible tight) sticking rubber seal - because the rubber seal gets dry against steel on the 2 mating surfaces. It has nothing to do with rusty threads or corrosion. Its just the way that a rubber square section seal seize up over time.

Try any cheap standard oil fiter removal tool - and you waste time & money. Proper tool is like the BOA strap wrench :
http://www.tool-up.co.uk/shop/diy/MISBOA.html

mezuk04 · Unread post by **mezuk04** » 23 Jan 2006, 12:28

Thanks for that Anders, I have just ordered the tool with the link you have provided.

Can you confirm that its a case of

1. Ride height to minimum (I shall be putting the car onto car ramps at the front).
2. Turn off the engine.
3. Release the pressure by the little screw valve at the front (only half a turn as to not lose the ball) and then tighten the valve back up.
4. Loosen them using the "new" tool I have just ordered.
5. Put a bit of LHM round the seal of the new spheres and hand tighten them into position.
6. Start the car, down the ramps and enjoy the nice new improved ride??

Is it a good idea to keep some spare LHM handy due to the spillage thats required to replace this or isnt it necessary?

Ive browsed the other threads but they never seem to answer the questions i specifically need for my own personal level of competence

AndersDK · Unread post by **AndersDK** » 23 Jan 2006, 14:16

Confirmed - you have a go 8)

Mandrake · Unread post by **Mandrake** » 23 Jan 2006, 19:01

AndersDK wrote:A proper removal tool is necessary to crack the (incredible tight) sticking rubber seal - because the rubber seal gets dry against steel on the 2 mating surfaces. It has nothing to do with rusty threads or corrosion. Its just the way that a rubber square section seal seize up over time.

I find it hard to believe that the rubber seal is the source of incredibly tight spheres. There is only a very small amount of compression of the seal, and a very small surface area, and IMHO there is no way that the seal can account for some of the incredibly tight spheres I've had to undo in the past.

What evidence do you base this theory on ?

IMHO It's just the same as any tight/difficult to remove bolt - overtightening and/or surface rust locking the threads or faces. (Perhaps even some metal to metal migration)

Regards,
Simon

mezuk04 · Unread post by **mezuk04** » 23 Jan 2006, 19:06

On another note, dont see any point creating another thread for this but am i being over caring by servicing the car every 5000 with the following

Oil
Oil Filter
Air Filter
Pollen Filter
Fuel Filter

I know that the last 3 are to be replaced much more than 5000 but for the sake of £20 every 5000 i dont see why i cant.

I found that when i left the fuel filter in the temptation for 10,000 the responsiveness i got back was quite surprising so made the effort of doing that with the oil change.

And the air and pollen filters....well im asthmatic and want to keep the cabin as clean as i can.

Just wondered if im being over silly at all

AndersDK · Unread post by **AndersDK** » 23 Jan 2006, 19:47

Simon -

Its not a theory - its the fact. Dry clean steel against dry clean rubber has - what friction do you think ? Think about tyres on steel rims and any homework attempts to replace a tyre

The sphere threads are on the oil side of the mounting and are in fact wetted by LHM once system is pressurised. Find any schematic showing detailed sphere mountings and you will instantly recognise it.

Despite the heavy use of road salt, despite the heavy (deep brown crispy) surface corrosion - of rear suspension spheres on DK cars - I have never seen rusty threads on spheres.
Its the rubber seal that grips. The longer rubber and steel stays together - the more the tendency to self vulcanise.

andmcit · Unread post by **andmcit** » 23 Jan 2006, 20:18

That strap wrench on the link looks a tad lightweigt!! Is that band fabric!?

I agree that the usual oil filter chain wrenches don't fare well with stubborn spheres but I do use the following when the proper Citroen band wrench is too chunky to gain access:

http://www.machinemart.co.uk/product.asp?p=040210037

It is akin to a motorcycle chain more than a bicycle!!

Andrew

Mandrake · Unread post by **Mandrake** » 23 Jan 2006, 20:38

AndersDK wrote:Simon -

Its not a theory - its the fact. Dry clean steel against dry clean rubber has - what friction do you think ? Think about tyres on steel rims and any homework attempts to replace a tyre

Yes rubber grips steel, but the amount of force compressing the rubber is relatively little. You have a seal that is 3-4 mm thick and only compressed by about 0.5mm. It is still not enough to account for the tightness of some spheres.

I would only consider it proven if someone did the maths on how much friction that amount of rubber could provide and how much torque would be required to free it - given that you have a large leverage ratio when gripping the outside diameter of a sphere working against a very small seal.

Until then it is still speculation IMHO.

The sphere threads are on the oil side of the mounting and are in fact wetted by LHM once system is pressurised. Find any schematic showing detailed sphere mountings and you will instantly recognise it.

Despite the heavy use of road salt, despite the heavy (deep brown crispy) surface corrosion - of rear suspension spheres on DK cars - I have never seen rusty threads on spheres.

It's true that the threads don't rust, but the faces do. Look at the same diagram and you'll see large flat mating faces on the outside edge of the seal - which have a larger surface area than the seal, and are direct metal to metal contact. (In the case of the pressure regulator, steel to steel)

On any sphere that I've found extremely tight invariably there is a significant amount of surface rust on the faces, which is one reason why I always lightly grease these faces. (Which never give problems when greased)

Another factor is the way in which the spheres let go when a tight sphere is finally broken free - it gives way suddenly and completely, usually with a good tap from a lump hammer and is then instantly free to turn within only a few degrees of turning - a good sign that there was a rust bond between the faces.

Jolting the joint with a seperate hammer like that (while applying steady torque to the strap spanner) shouldn't make any difference if it was just the rubber gripping.

I'm sure the rubber contributes to the difficulty undoing a sphere, but I don't think it accounts for really stubborn spheres that need "cracking".

Regards,
Simon

AndersDK · Unread post by **AndersDK** » 23 Jan 2006, 21:15

Simon -

There are no mating faces metal to metal - on any sphere mounts.
That would not work as the seal would then not be allowed to function.
The tightness of the joint relies 100% of the slightly compressed seal between the 2 metal surfaces.

AndersDK · Unread post by **AndersDK** » 23 Jan 2006, 21:29

andmcit wrote:That strap wrench on the link looks a tad lightweigt!! Is that band fabric!?

I agree that the usual oil filter chain wrenches don't fare well with stubborn spheres but I do use the following when the proper Citroen band wrench is too chunky to gain access:

http://www.machinemart.co.uk/product.asp?p=040210037

It is akin to a motorcycle chain more than a bicycle!!

Andrew

Andrew -

Steel chain tools are in fact dangerous to use on circular steel members to be unscrewed. Because steel to steel has very low friction. This makes it very prone to slip while you apply your last bit of hand torque. For some reason your hands always stops against something VERY hurting

Its kind of an outdated old fashion tool - because "thats what we always use when its stuck".

Kowalski · Unread post by **Kowalski** » 23 Jan 2006, 21:30

The sphere seals are a square sectioned O ring, and they fit into a space the same size and shape as them, they don't deform in the same way that a round O ring would, they can't deform because there is no room.

Also, seals have a tendancy to swell and metal has a tendancy to rust, the seal tends to be covered in LHM when you tighten it but the LHM can disappear from the outer contact area and dirt can get in too. There are plenty of reasons why things get tight. Then of course you get the fact that some people tighten spheres rather more than they should be tightened.