Freelander 1 Yet another VCU thread

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Qoute
"If a new VCU is indicated, where's the best place to buy one - and genuine new versus pattern or reconditioned? Price is important, but there's no point wasting the time and the effort or cost of the replacement work by buying **** parts, and I do plan to keep the car for as long as I can."

Just adding my half a six pence worth here........

If it does need replacment............
You can either recon this yourself (Search the forums). Buy a recon unit from Bell engineering and fit yourself about £200+P&P without bearings or with about £250+P&P (Both options are exchange). Or buy a new unit from http://www.ashcroft-transmissions.co.uk/freelander-parts/fl-viscous-coupling.html currently £250 +VAT +P&P less bearings (No exchange) :cool:
 
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I've read volumes a lot of really interesting science out there investigating how VCUs work. The volumes of info being compressed into a nutshell quite eloquently by Nodge...
Nodge68 said:
I believe a pressure rise in the VCU that makes the fluid more viscose, when it's taking torque. I'm sure that's the theory anyway.
The VCU fluid does seem to thicken when cold, but not much.
Click to expand...
That's not quite accurate as the pressure activates mechanical grip between plates, but the result (in how the VCU distributes torque) is the same.

I think LZ, more than anywhere else, has put the most investigation into testing VCUs and finding out if they are fit-for-purpose. The One Wheel Up Test, although not a perfect test of all VCU operations, is backed up with so much data (in the form of results) now that it simply can't be ignored and is the only real quantifiable test.

The one area which is still complete guess work is what makes them degrade. We can assume that the more uneven the tyres are the quicker a VCU will degrade, we can hypothesise about extended periods of inactivity, varying rates of activity etc - but it is only guess work - there is no data or science to back anything up (that I'm aware of). There was an LZ thread a while back where someone found some science on it, and no doubt some LZ experience and data might have extended our awareness of degradation, but I believe that thread died after being hijacked by someone repeatedly saying to reverse in circles - not sure who that might have been!
 
GrumpyGel said:
I've read volumes a lot of really interesting science out there investigating how VCUs work. The volumes of info being compressed into a nutshell quite eloquently by Nodge...

That's not quite accurate as the pressure activates mechanical grip between plates, but the result (in how the VCU distributes torque) is the same.

I think LZ, more than anywhere else, has put the most investigation into testing VCUs and finding out if they are fit-for-purpose. The One Wheel Up Test, although not a perfect test of all VCU operations, is backed up with so much data (in the form of results) now that it simply can't be ignored and is the only real quantifiable test.

The one area which is still complete guess work is what makes them degrade. We can assume that the more uneven the tyres are the quicker a VCU will degrade, we can hypothesise about extended periods of inactivity, varying rates of activity etc - but it is only guess work - there is no data or science to back anything up (that I'm aware of). There was an LZ thread a while back where someone found some science on it, and no doubt some LZ experience and data might have extended our awareness of degradation, but I believe that thread died after being hijacked by someone repeatedly saying to reverse in circles - not sure who that might have been!
Click to expand...

My VCU is timing at just under a minute with 5Kg at 1.2M. However I do feel some drag when on full lock. This was recognised by LR and instructed dealers to advise owners of its normality. I suspect that if the VCU was new, little drag would be felt. However as the VCU ages and stiffens, drag on lock progressively increases.

Although apparently my IRD is going to explode according to that same hijacker!! I'm confident that some drag is normal and of no consequence. If the maths is done. The actual drag in Nm or FtLb is very low. Definitely a lot less than the torque transmitted when driving off road, in front slip situations.
 
Nodge68 said:
My VCU is timing at just under a minute with 5Kg at 1.2M. However I do feel some drag when on full lock. This was recognised by LR and instructed dealers to advise owners of its normality. I suspect that if the VCU was new, little drag would be felt. However as the VCU ages and stiffens, drag on lock progressively increases.

Although apparently my IRD is going to explode according to that same hijacker!! I'm confident that some drag is normal and of no consequence. If the maths is done. The actual drag in Nm or FtLb is very low. Definitely a lot less than the torque transmitted when driving off road, in front slip situations.
Click to expand...
If you don't feel some level of drag then your car is in Mondo mode.
Wonder where he went? :rolleyes:
 
Just checking on the way in which the beveled washers fit when fitting the propshaft bearing. Rave doesn't even show them, many photos and diagrams on this site show them bevel edge outermost from the VCU. If they only exist to keep muck out of the bearing would they do this job better if they were bevel edge in towards the bearing??

Just a thought - is there a reason why they can't be fitted this way around? Anyone tried plastic washers to keep bearings clean (either side of prop bearing??)
Thanks..............
 
GrumpyGel said:
That's not the attitude Ali!

VCUs are like spouses - if they're happy, then you're happy. If they're not, then you're ****ed. Keep them happy and life's sweet :)
Click to expand...
Wives don't like to be dumped in the garage when they're unhappy and languish there until you get them reconditioned, or sent back for a newer model.
 
Interesting and numerous though the wife / VCU analogy is. I think my question may have been lost !!

Keen to hang on to my existing VCU (& wife!) ;)

So again.............

Just checking on the way in which the beveled washers fit when fitting the propshaft bearing. Rave doesn't even show them, many photos and diagrams on this site show them bevel edge outermost from the VCU. If they only exist to keep muck out of the bearing would they do this job better if they were bevel edge in towards the bearing??

Just a thought - is there a reason why they can't be fitted this way around? Anyone tried plastic washers to keep bearings clean (either side of prop bearing??)
Thanks..............
 
andyfreelandy said:
Interesting and numerous though the wife / VCU analogy is. I think my question may have been lost !!

Keen to hang on to my existing VCU (& wife!) ;)

So again.............

Just checking on the way in which the beveled washers fit when fitting the propshaft bearing. Rave doesn't even show them, many photos and diagrams on this site show them bevel edge outermost from the VCU. If they only exist to keep muck out of the bearing would they do this job better if they were bevel edge in towards the bearing??

Just a thought - is there a reason why they can't be fitted this way around? Anyone tried plastic washers to keep bearings clean (either side of prop bearing??)
Thanks..............
Click to expand...
I've seen them fitted both ways round but TBH I'm not sure it matters that much, all the bearings I've seen that were duff it was the rubbers were the problem.
 
andyfreelandy said:
Interesting and numerous though the wife / VCU analogy is. I think my question may have been lost !!

Keen to hang on to my existing VCU (& wife!) ;)

So again.............

Just checking on the way in which the beveled washers fit when fitting the propshaft bearing. Rave doesn't even show them, many photos and diagrams on this site show them bevel edge outermost from the VCU. If they only exist to keep muck out of the bearing would they do this job better if they were bevel edge in towards the bearing??

Just a thought - is there a reason why they can't be fitted this way around? Anyone tried plastic washers to keep bearings clean (either side of prop bearing??)
Thanks..............
Click to expand...
The beveled washers are fitted bending away from the bearing - I agree it looks wrong - but that is the way they go. People have installed them the other way round and it does cause problems.

TBH the setup isn't problematic - the genuine bearings do last well - its only the cheap ones that fail early and I don't suppose that would change no matter how much you try and protect them.
 
GrumpyGel said:
The beveled washers are fitted bending away from the bearing - I agree it looks wrong - but that is the way they go. People have installed them the other way round and it does cause problems.

TBH the setup isn't problematic - the genuine bearings do last well - its only the cheap ones that fail early and I don't suppose that would change no matter how much you try and protect them.
Click to expand...

Agreed 100%. Flingers definitely face away from the bearings.

It is possible to replace the bearing race with a better quality replacement, providing the support rubber is OK.
 
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Thanks, other way around looks logical and more likely to prevent dirt ingress, but hey - rules is rules !
I am just in process of refurbing a VCU and fitting a pair of GKN bearings so want them to last. May look at plastic washers either side of the bearing if I can see a way of doing it so as not to rub on moving parts !
Will photo the refurb - drilling, tapping to 17mm and fitting flush fitting allen key sump plugs with copper washers. Am going to weigh it before and after to see if this helps with fluid measurement. Also, having confirmed a good solvent, I will connect one new port to my trusty degreasing pump and bath and let the cleaner run through it for a day or so. Then repeat with clean until clear. Then simply a matter of adding fluid change to the servicing schedule ! Watch this space...........
 
andyfreelandy said:
Thanks, other way around looks logical and more likely to prevent dirt ingress, but hey - rules is rules !
I am just in process of refurbing a VCU and fitting a pair of GKN bearings so want them to last. May look at plastic washers either side of the bearing if I can see a way of doing it so as not to rub on moving parts !
Will photo the refurb - drilling, tapping to 17mm and fitting flush fitting allen key sump plugs with copper washers. Am going to weigh it before and after to see if this helps with fluid measurement. Also, having confirmed a good solvent, I will connect one new port to my trusty degreasing pump and bath and let the cleaner run through it for a day or so. Then repeat with clean until clear. Then simply a matter of adding fluid change to the servicing schedule ! Watch this space...........
Click to expand...
Great idea going for sump plugs, should make it way easier to get the gunge out and the fluid in, what tap are you using to thread it?
 
Previous post question got missed in the banter !
SO ...........
Did anyone compare the time for a 45 deg turn with VCU on the car to the time for a 45 degree with VCU off the car?

If rear axle ratio is about 3:1 then would it be about 1/3 of the time - or is it not that simple??
Just thought that if we knew the conversion factor for on or off the car we can test when refurbed before fitting !

Just bought a tight VCU to refurb and it times at 25 secs on the bench. would this have been about 75 secs on the car??
 
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