Vcu torque test

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gazza666

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Vcu torque test results
What I did
Chock front wheels
Hand brake off
In first gear
Jacked off side rear wheel up
Take centre cap of wheel
Set my torque wrench to 300Nm with 32mm socket on the end
Placed on hub nut and turned wheel (wheel and vcu turned ok)
Tried 200Nm wheel and vcu turned ok
The lowest setting on mine which I could turn the wheel ( vcu )was 75 lbf/ft 101nm
My fl as done 80k miles I was quite surprised that not much torque is needed to turn the Wheel (vcu)
You must remember when doing this test that the wheel (vcu) will turn slowly when using 101nm
Even at greater torques you can’t expect the wheel to turn fast
Just set you torque wrench to 101nm 75lbf/ft and apply constant pressure and the wheel will slowly turn round if you try to speed it up your torque wrench will click
I am quite satisfies my vcu is ok and in good condition
hope this helps somebody:)
 
Thats great.

Makes you wonder why some vcus fail at only 30k when some some can do over 100k. I wonder if it is down to dodgy vcus or different driving styles.
 
gazza666 said:
Vcu torque test results
What I did
Chock front wheels
Hand brake off
In first gear
Jacked off side rear wheel up
Take centre cap of wheel
Set my torque wrench to 300Nm with 32mm socket on the end
Placed on hub nut and turned wheel (wheel and vcu turned ok)
Tried 200Nm wheel and vcu turned ok
The lowest setting on mine which I could turn the wheel ( vcu )was 75 lbf/ft 101nm
My fl as done 80k miles I was quite surprised that not much torque is needed to turn the Wheel (vcu)
You must remember when doing this test that the wheel (vcu) will turn slowly when using 101nm
Even at greater torques you can’t expect the wheel to turn fast
Just set you torque wrench to 101nm 75lbf/ft and apply constant pressure and the wheel will slowly turn round if you try to speed it up your torque wrench will click
I am quite satisfies my vcu is ok and in good condition
hope this helps somebody:)
Click to expand...

So you have tight turning at full lock but a vcu that checks out OK. Can we then conclude that brand new they run free but soon begin to tighten, hence the overall view that they all run tight? I will do this test next weekend - thanks Gazza.
 
wot we need now is the results of lots of peeps tests, to get a range of values - some for good, VCUs and some for knackered ones, so that it is easier to identify what is acceptable, what is suspect and what is definately knackered. Dont forget that VCUs can fail in constant slip mode too.
 
Hello Boyz, :D

I had a conversation with guys from Birmingham; they do reconditioning of VCU's and we had a deep thoughts about why VCU is failing on a different car in different time: all is down to how often and how long you have to use VCU. If you are doing loads of tight turns (hello London) and very often, gel will heat up more often and degrade quicker than on others used mainly for long runs. Don't forget: VCU is constantly sending "some" torque (about 1-3%) to the rear diff. That's why on earliest models you had problems with lack of synchro between IRD -> VCU -> rear diff, wrong ratios and VCU working "overtime". I got my with 31000 miles from North England and after working 15000 in London I had situations where with fully loaded car on the tight turn I've felt opposite rear wheel being under control of ABS (spinning too fast) as the VCU couldn't compensate any more (unnecessary giving too much torque for the rear diff).
 
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howardo:

Most likely, this car was not design to work on the farmer's field and pull cow head's off :)hysterically_laughi), that's car with off road capabilities. Mainly to run on the road. Look at Defender's Central Diff or Disco's.

Look at HDC, after going down hill a lot, your ABS may stop working after reaching too high temp (and they will heat up... really...), this is even a warning in one of the manuals. Somewhere.

I don't think I will get my wings after a Red Bull just because a TV advert is saying so...
 
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Hi All,
About 6 mths ago it became quite difficult to reverse my td4 into a tight space at my local asda carpark, it needed more revs, the V.C. appeared to be tightening up. So I fitted a new V.C. , what a difference , reversing into to tight places is now no problem. Driving up a steep grassy hill, the rear wheels sometime spin and the abs comes on, proving that there is drive to the rear wheels.
Also when turning a circle on full lock, in the local carpark, if I depress the clutch the car comes to a quick stop but does not attempt to go slighty backwards ,transmission unwind.
Here,s a site I found on the net, it maybe of interest, but when reading it, bare in mind the car in this example is rear engined. VCTest
Regards, brian
 
I like the disclaimer on the VC test

Warning! You could conceivably get killed or kill someone performing this test.

If in doubt that th VC is in 'slip mode' the same thing could be done with the FL,
jack up the front end with the front wheels removed,

lower on to skates supporting the subframe/chassis, not the wheels

Put into 1st

let clutch out, front wheels should rotate then VC engage

FL creeps forward due to drive at rear wheels


Warning! You could conceivably get killed or kill someone performing this test LOL
 
Here's my VCU torque reading from our TD4. It's now done 64k and is 5 1/2yrs old.

The lowest setting that would very slowly turn the hub (VCU slipping) was 35lbs/ft.

I decided to try a "Chaser method" and eliminate the gearing of the diff. I used an off cut of flat steel to make a simple bolt on adapter for the disconnected propshaft flange (see pic).

In this way I was able to turn the VCU with the torque wrench set to just 20lb/ft, again very slowly.

Any attempt to make it slip quickly takes much more torque and I still wonder how much strain it is putting on the transmission at say 70mph.
 

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Chaser said:
Here's my VCU torque reading from our TD4. It's now done 64k and is 5 1/2yrs old.

The lowest setting that would very slowly turn the hub (VCU slipping) was 35lbs/ft.

I decided to try a "Chaser method" and eliminate the gearing of the diff. I used an off cut of flat steel to make a simple bolt on adapter for the disconnected propshaft flange (see pic).

In this way I was able to turn the VCU with the torque wrench set to just 20lb/ft, again very slowly.

Any attempt to make it slip quickly takes much more torque and I still wonder how much strain it is putting on the transmission at say 70mph.
Click to expand...

Great results
Shows a big difference on my freelander which has done 82k miles and is 9 years old
And the torque lowest torque setting I could get the wheel (vcu) to turn was 75lb/ft
So I wonder what the torque would be, when we could say the vcu is past its sell buy date
 
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Nice ickle adaptor bar ;)

It was something like that I was thinking of doing in a previous thread, it could easily be posted from one person to the next.

i notice a square flange on the rear, on the early ones the flange is round.

Using Gaz's protocol,

125Nm both sides, but this was incredibly slow, only turning the wheel approx 5degrees every second.

Previously the torque value was well over twice this, to allow the wheel to rotate 20-25 degrees every second approx.

I now have the prop off the FL, will get some more figures at the weekend
 
Its 9 oclock on a saturday night, I cant believe i'm doing this. Must have drunk to much HOBGOBLIN

51 plate V6 auto, 58,000 miles Owned from new, don't notice any dragging or problems when turing at low speeds on full lock.

Only checked from offside wheel
Could just move it very slowly at 20lb/ft (28Nm)
Tried at 15 lb/ft but couldn't keep a constant pressure on the torque wrench long enough without 'clicking' it.
 
Just another thought, didn't LR change the IRD ratio about 2001 to try and prevent the VCU's seizing ? If so older cars will 'cook' the VCU quicker than newer ones.
 
ianda12 said:
Its 9 oclock on a saturday night, I cant believe i'm doing this. Must have drunk to much HOBGOBLIN

51 plate V6 auto, 58,000 miles Owned from new, don't notice any dragging or problems when turing at low speeds on full lock.

Only checked from offside wheel
Could just move it very slowly at 20lb/ft (28Nm)
Tried at 15 lb/ft but couldn't keep a constant pressure on the torque wrench long enough without 'clicking' it.
Click to expand...

You know you cant get enough of it
Another great set of results we have a range now of 28NM to 125NM
if you where to do a direct reading from the prop perhaps you could have turned the vcu at about 12lb/ft
Going on your results
You have confirmed what I have said in one of my previous post when I drove new freelanders at Gaydon that , you don't notice any dragging or problems when turing at low speeds on full lock.
With that torque reading I can see why
I am now wondering if my 75lb/ft is a little on the high side
 
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checked out the vcu on my xedi year2000 Got a reading of 35lbs/ .There is no brakeing
effect when reversing on full lock .I have recently done a modificaton to my vcu to eliminate ird wind up as it was starting to bind up severly and it has been great
 
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