Vcu

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gazza666 said:
So what are you saying?
A new vcu slips the same as on old vcu one that has done 80k miles till the point it seizes up
The point is we all know the vcu will slip and produce drag
But does that drag increase the more miles the vcu does probably yes
So at what point do we say the vcu as no good and putting extra strain on the IRD
Click to expand...
No i'm not saying that. If you reread my post you'll see that i say that a worn vcu will not work as efficiently as a new one.

The point at which it begins to be no good depends on how you use your vehicle. It is going to be different for each individual.
 
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If you are still paranoid about the vcu putting stress on the ird after you have tried all the tests then you have no option but to replace it. They say that this should be at about 70k.
 
a few thing i have read

When I done my test never used socket on hub nut
this might be better way to test it
To test
Park car on the flat.
Hand brake off.
IN FIRST GEAR.
Chock front wheels.
Jack up one side of the rear.
On the central hub nut of the lifted wheel, fit a socket (32mm?)and a 2' or 3' bar.
Lean on bar, in either direction.
If the bar moves smoothly and reasonably easily, OK
If VERY stiff and/or notchy, probably duff.
 
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gazza666 said:
a few thing i have read

When I done my test never used socket on hub nut
this might be better way to test it
To test
Park car on the flat.
Hand brake off.
IN FIRST GEAR.
Chock front wheels.
Jack up one side of the rear.
On the central hub nut of the lifted wheel, fit a socket (32mm?)and a 2' or 3' bar.
Lean on bar, in either direction.
If the bar moves smoothly and reasonably easily, OK
If VERY stiff and/or notchy, probably duff.
Click to expand...

i'm glad you've found a test you're happy with.
 
Thanks Howardo
This might be the way to test eg
If I put a 32mm socket on the hub nut and set my torque wrench to 295 lbf/ft
Which is the torque setting for the hub nut
When I apply the pressure the vcu should slip if not ime in the **** because my torque wrench only goes to 300lbf/ft
You can see the theory behind what ime trying to do
By varying the settings on my torqe wrench I can find the required torque to turn the vcu
Then can compare it against a new one if anybody has a new one and can do the test
Just interested to see the comparison
I will do the test and post the results
 
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250Nm no probs and transmission still kept turning, I didn't want to take it higher than that on the driveshaft nut. It is torqued to 210Nm on ths shaft.

vcu - 20k - 25k miles, nearly 9 years old

I'd rather do the torque value inline, the rear diff gives you a bit of 'gearage'
 
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Northern Irelander said:
250Nm no probs and transmission still kept turning, I didn't want to take it higher than that on the driveshaft nut. It is torqued to 210Nm on ths shaft.

vcu - 20k - 25k miles, nearly 9 years old

I'd rather do the torque value inline, the rear diff gives you a bit of 'gearage'
Click to expand...
could you repeat that you said you dont want to take it higher than the hub nut torque of 210NM but you say the vcu turned at 250NM
it must be lower than 250NM
 
gazza666 said:
could you repeat that you said
Click to expand...
Ahh sed ;)
Northern Irelander said:
250Nm no probs and transmission still kept turning, I didn't want to take it higher than that on the driveshaft nut. It is torqued to 210Nm on ths shaft.

vcu - 20k - 25k miles, nearly 9 years old

I'd rather do the torque value inline, the rear diff gives you a bit of 'gearage'
Click to expand...

Movement is smooth and steady, moving the hub nut through a 90degree rotation.

If anything its about the same amount of torque when using the Ashcroft method.
 
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Northern Irelander said:
Ahh sed ;)


Movement is smooth and steady, moving the hub nut through a 90degree rotation.

If anything its about the same amount of torque when using the Ashcroft method.
Click to expand...

ok thanks I will do the test and post back
I will find out how much torque it takes to move the vcu on my fl that has done 80k miles
as you say the diff will offer some resistance and better being direct
if I do it on the offside rear wheel then I will be going in the same rotation
as the wheel and will be tightening the hub nut as well instead of undoing it
so i will be going clockwise
 
landa12: Please dont use your wheel nuts to test the VCU. They should only be torqued to 115Nm. At best you will stretch them and at worst break them and did you read the threads about the problems of changing wheel studs on the rear, you have to split the bearings and that means replacement.

From all the talk over the ether on VCUs it would seem that they are over specified. (I was going to say "too good"!) If they didn't require so much torque to make them slip they would act as a torque limiter and not pass the load on to the IRD which then becomes the weak point. As it is all the engine torque can go down the prop shaft when the front wheels slip. A less viscous fluid could save a lot of money!
 
vic.middleton said:
landa12: Please dont use your wheel nuts to test the vcu. They should only be torqued to 115nm. At best you will stretch them and at worst break them and did you read the threads about the problems of changing wheel studs on the rear, you have to split the bearings and that means replacement.

From all the talk over the ether on vcus it would seem that they are over specified. (i was going to say "too good"!) if they didn't require so much torque to make them slip they would act as a torque limiter and not pass the load on to the ird which then becomes the weak point. As it is all the engine torque can go down the prop shaft when the front wheels slip. A less viscous fluid could save a lot of money!
Click to expand...
i am not using the wheel nuts ime using the driveshaft hub nut to test the torque which as a tightening torque of 400nm
I have changed the wheel stud on the back without splitting the bearind
 
gazza666 said:
i am not using the wheel nuts ime using the driveshaft hub nut to test the torque which as a tightening torque of 400nm
I have changed the wheel stud on the back without splitting the bearind
Click to expand...

Don't panic Gaz, Vic was giving ianda12 a few pointers.

400Nm :eek: was the nut flange unstaked before checking? Or are you saying your VCU starts to take up the strain at 400Nm
 
Northern Irelander said:
Don't panic Gaz, Vic was giving ianda12 a few pointers.

400Nm :eek: was the nut flange unstaked before checking? Or are you saying your VCU starts to take up the strain at 400Nm
Click to expand...
I have not tried this yet but I am going to use the hub nut to do the test
the hub nut has a tightening torque of 400nm
so I am going to set my torque wrench to say 100 nm and see if i can turn the wheel (vcu) before my torque wrench clicks if not i will set torqu at 200nm and so on till i get a reading when the wheel (vcu) slips
my torque wrench will only go upto 400nm which is the limit of hub nut torque ,so I dont want to go past that for fear of damaging hub nut
so i hope the vcu slips before then
my fl as done 80k miles and when I post results will be a starting point for anybody else who wishes to do the test
woul be nice to compare against a fl with a new vcu
 
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Picking through Rave it's impossible to say definitively how tight the vcu should be when testing in a diy fashion. These extracts imply that turning by hand should be relatively easy with a considerably significant resistance at 75rpm.
AT 60k, mine is VERY tight to turn with an 18" pry bar in one of the prop ujs so there must be degradation of the fluid/gel. The big question is how much degradation should I ignore before bottling out and replacing it. A guy at the stealers said it 'felt normal' when he drove it but i'm not sure I trust him.



so in most conditions the vehicle is effectively front wheel drive,
with the rear wheels turning the rear propeller shaft
slightly faster than the IRD drives the front propeller
shaft. Since the speed differential is low, the
increase in viscosity of the silicon jelly is marginal
and there is little resistance to relative rotation of the
slotted discs.
When there is a significant speed differential
between the front and rear propeller shafts , e.g. the
front wheels lose traction or traversing rough terrain,
the viscosity and resistance to rotation of the silicon
jelly increases to a level that slows or stops relative
rotation of the slotted discs.


Viscous coupling
Rating:
Max 440 Nm (325 lbf.ft) @ 75 rpm
Min 360 Nm (265 lbf.ft) @ 75 rpm
 
gazza666 said:
I have not tried this yet but I am going to use the hub nut to do the test
the hub nut has a tightening torque of 400nm
so I am going to set my torque wrench to say 100 nm and see if i can turn the wheel (vcu) before my torque wrench clicks if not i will set torqu at 200nm and so on till i get a reading when the wheel (vcu) slips
my torque wrench will only go upto 400nm which is the limit of hub nut torque ,so I dont want to go past that for fear of damaging hub nut
so i hope the vcu slips before then
my fl as done 80k miles and when I post results will be a starting point for anybody else who wishes to do the test
woul be nice to compare against a fl with a new vcu
Click to expand...

Gaz, where did you get that 400Nm value from mate? it is normally 210 ish Nm on all driveshaft nuts, then the flange is staked to stop shaft recess.
 
Northern Irelander said:
Gaz, where did you get that 400Nm value from mate? it is normally 210 ish Nm on all driveshaft nuts, then the flange is staked to stop shaft recess.
Click to expand...
I have got these values out of my haynes manual is states
Driveshaft nut tightening torque 400NM or 295 lbf/ft I have checked this it is right this applies to front and rear
210nm is only about 155lbf/ft the driveshaft nut is torqued tighter than that
 
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gazza666 said:
I have got these values out of my haynes manual is states
Driveshaft nut tightening torque 400NM or 295 lbf/ft I have checked this it is right this applies to front and rear
210nm is only about 155lbf/ft the driveshaft nut is torqued tighter than that
Click to expand...

Ahh thanks I stand corrected, just dug the book of lies out myself and in black and white it says 400Nm. Haynes publishers are getting worse.

I use an official MG workshop manual for reference figures.
210Nm is MG value, the driveshaft nuts are exactly the same as LR ones.
Power and torque values from the MG engines are the same if not far and beyond what a Freelander will put out at the wheels.

I can honestly say I've never torqued a driveshaft nut to 400Nm ;)
 
I have problems with my Viscous coupling at the moment (FL 1 1.8P X reg), the steering gets really heavy when trying to park and the damper is rattling. A mechanic who only deals with landy's told me the VCU needs replacing and spoke about reconditioned units being available, I don't believe this as it seems to be a sealed for life unit ,can anyone answer the following;
  • my damper has an external diameter of approx 174mm, most 4 x 4 sites sell a replacement kit but only for 150mm diameter damper, what is different between the earlier model FL1's and the newer one's?
  • are recon units available?
  • I took the whole prop off until I get a chance to fix it, however, I was told if I drive around with the whole prop off it would knacker up the gearbox. will it??? The steering feels perfect with the prop off but now I'm worried I'm going to get more expense
  • will the newer 2001 onwards prop shaft and VCU fit on my 2000 model, the VCU is much larger than the newer one's.
Any advice or actual knowledge welcome.
 
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