vcu recon

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thequeenscheese

thequeenscheese

Well-Known Member
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Greater Manchester
sorry if this has been covered.
now im think of doing my vcu soon as a matter of course ill prob get a bell recon for £200 plus mine, but i was wondering what it takes to recon the vcu and why cant i do it myself or my trusty mechanic?
 
Not done anything with it really......My other cars been giving me trouble.....

I need to drill holes as others have said.....I did try welding to the ball bearing but this did not work....So I will have to find a suitabe drill bit and drill the 10mm of steel to make drain and fill holes.....

Its probably easier to get a recon one from bell thou £200 and no hassle.....
 
Your prob right lol I still like the idea of a mechanical replacement tbh it must be doable this vcu and changing viscosity fluids wasn't great Idea in the fits place.
 
Yeah I have to agree....the vw guys tend to do it a lot, but their vcu,s come apart and they have access to the fluids and parts etc..... bigger scence i presume?.......drilling 10mm of hard steel is putting me right off.....just drilling 2mm takes forever and blunts the bit.....unless im doing it wrong?????
 
used a 6mm diamond core drill to remove the bearings on mine ! its the same type of drill used to drill ceramic tiles and glass ! i'll take a pic of it tomorrow if I get chance they can be bought from b&q or a good tile stockists ! used a cordless drill on slow and don't let the bit get too warm !
still working on the viscous fluid though ! anybody know where to get any !!!
 
Is it just a case of changing the fluid in the vcu and it's good to go again?
Or is more complicated than that?

I've recently took mine off as it was starting to get abit stiff due to previous owner running miss match tires. If it can be done by myself rather than forking out £200+ then I might give it ago
 
Some good quality hard tek screws might be a good idea we use them on building sites to secure brick ties to steel puller and good quality ones will go through most steels (pitty the firm's usually by ****e ones) and there about 6mm one thing I've learnt doing that is if you have no cutting compound evian squirty bottle filled with water helps I just gotta keep the screw/drill but cool and the hole, diamond core bit or tungstan the way to go tho
 
jedi said:
Yeah I have to agree....the vw guys tend to do it a lot, but their vcu,s come apart and they have access to the fluids and parts etc..... bigger scence i presume?.......drilling 10mm of hard steel is putting me right off.....just drilling 2mm takes forever and blunts the bit.....unless im doing it wrong?????
Click to expand...

Drilling 10mm of steel isn't difficult. A sharp quality drill and a cutting fluid to keep it sharp is all that is needed.
It's not necessary to drill out the ball bearing plugs. Just drill some new holes near by.
 
thequeenscheese said:
Why 10mm etc I'm sure you could go bigger ooer less of a nipple and more of a drain plug easier to get fluid in and out..
Click to expand...

The end plates are 10mm thick. This means you have to drill a 10mm deep hole to access the fluid. ;)
The hole diameter can be whatever works with whatever you use to get the fluid in/out.
 
So the drill has to run at a slow speed and not get hot.....

Ive heard 30,000 and 100,000 cst fluid being used......and again it depends on how much you put in......trial and error I supose...


There's a guy on ebay selling the fluid....its £34 inc p&p for 500ml

Alchemist17

25,000 cst
30,000 cst
100,000 cst

He may be able to get other grades :)

He thinks the Freelander grade is around the 100,000 cst range

$_3.JPG
 
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The vcuis old hat really these days so I'd imagine there has be advances in the fluid tech so I wonder if here's a better replacement fluid to use with better longevity?

Also freebies are allover the world and if this fluid is meant to be temperature sensitive how do the freebies in qatar Saudi etc get on do they have different fluids?? If so would it be better for us to use also?
 
jedi said:
So the drill has to run at a slow speed and not get hot.....

Ive heard 30,000 and 100,000 cst fluid being used......and again it depends on how much you put in......trial and error I supose...


There's a guy on ebay selling the fluid....its £34 inc p&p for 500ml

Alchemist17

25,000 cst
30,000 cst
100,000 cst

He may be able to get other grades :)

He thinks the Freelander grade is around the 100,000 cst range

$_3.JPG
Click to expand...

Is this a non newtonian fluid or just thick silicone oil? If it's the latter, it ain't the correct stuff ;)
 
Nodge68 said:
Is this a non newtonian fluid or just thick silicone oil? If it's the latter, it ain't the correct stuff ;)
Click to expand...

Looking at the pic - I googled 'silicon oil' - that took me to a Wiki page for silicon oil. That had a "See also Polydimethylsiloxane" - which is the name on the tub in the picture. Reading that page it says that Polydimethylsiloxane is also known as dimethicone and...

Dimethicone is also the active silicone fluid in automotive viscous limited slip differentials and couplings. This is usually a non-serviceable OEM component but can be replaced with mixed performance results due to variances in effectiveness caused by refill weights or non-standard pressurisations.

Its obviously doesn't say whether this is what GKN actually use or what grade if they do - but it does look like the right type of fluid.
 
On GKN's website glossary - they describe the Viscous coupling as such...

The viscous coupling or viscous LSD is often found in all-wheel-drive vehicles. It is commonly used to link the back wheels to the front wheels so that when one set of wheels starts to slip, torque will be transferred to the other set. The viscous coupling has two sets of plates inside a sealed housing that is filled with a thick fluid. One set of plates is connected to each output shaft. Under normal conditions, both sets of plates and the viscous fluid spin at the same speed. When one set of wheels tries to spin faster, perhaps because it is slipping, the set of plates corresponding to those wheels spins faster than the other. The viscous fluid, stuck between the plates, tries to catch up with the faster disks, dragging the slower disks along. This transfers more torque to the slower moving wheels (the wheels that are not slipping).

There is no mention of heat changes. I'm not so sure heat plays a part at all.

The WIKI description of Polydimethylsiloxane says....

PDMS is viscoelastic, meaning that at long flow times (or high temperatures), it acts like a viscous liquid, similar to honey. However, at short flow times (or low temperatures), it acts like an elastic solid, similar to rubber. In other words, if some PDMS is left on a surface overnight (long flow time), it will flow to cover the surface and mold to any surface imperfections. However, if the same PDMS is rolled into a sphere and thrown onto the same surface (short flow time), it will bounce like a rubber ball.

Given these descriptions, it looks like the rapid changes in the VCU plates, eg when front wheels slip, is "short flow time" - so the PDMS is like (solid) rubber and will drag the next plate along. Where as slow changes in the VCU plates, eg allowalbe differences in tyre wear, is " long flow times" - so the PDMS is like honey and allows the plates to slip.

Given the PDMS description - if heat were generated - the silicon would be more likely to become fluid rather than solid.
 
Its what they put in the vw vcus...they seem very knowledgeable on the subject:)

Heat has nothing to do with the fluid. Heat is a by product of the shearing action on the fluid...The shearing action of the plates thickens the fluid and as a result heat is generated......applying heat to the fluid does not thicken it.

So I believe:eek:
 
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jedi said:
Its what they put in the vw vcus...they seem very knowledgeable on the subject:)

Heat has nothing to do with the fluid. Heat is a by product of the shearing action on the fluid...The shearing action of the plates thickens the fluid and as a result heat is generated......applying heat to the fluid does not thicken it.

So I believe:eek:
Click to expand...

So heat isn't the reason it fails?
 
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