davidsmith1307 · Oct 1, 2015

In which case it would be good to try taking it off and putting it back on in the 'same' position. This might tell us whether the tolerance on the holes is enough to cause a problem.
Then it would be a score draw between us and @jamesmartin and I'd take that any day!

SamA90 · Oct 1, 2015

@Hippo, spotted what you said in that thread you linked

"A brand new vcu is machine welded. It's true the viscous fluid inside falls to the bottom of the vcu if left standing. But those like me who have drained a vcu know the fluid moves. Not as quick as water but it does move faster than you would think, considering it's similar to slime. So that won't make it vibrate unless the fluid has turned solid/hard."

considering my VCU was stiff as buggery on the wheel up test, could that be causing the rumble? If the fluid is thick/knackered, would it stay in one place after sitting overnight and therefore be thrown around the vcu when I get to speed, causing the shake?

Hippo · Oct 1, 2015

SamA90 said:
@Hippo, spotted what you said in that thread you linked

"A brand new vcu is machine welded. It's true the viscous fluid inside falls to the bottom of the vcu if left standing. But those like me who have drained a vcu know the fluid moves. Not as quick as water but it does move faster than you would think, considering it's similar to slime. So that won't make it vibrate unless the fluid has turned solid/hard."

considering my VCU was stiff as buggery on the wheel up test, could that be causing the rumble? If the fluid is thick/knackered, would it stay in one place after sitting overnight and therefore be thrown around the vcu when I get to speed, causing the shake?

Not really. The vcu contains a set of plates connected via the axle in the middle to one prop shaft, and every other plate connect to the inside of the outer case of the vdc to the other propshaft. If the props are rotating at differing speeds then the plates will also rotate at the same differing speed. Hence mixing up the fluid inside as the plates cut through it. It doesn't take that long for the fluid to move round the vcu when this happens, to average itself out around the vcu. The "book" rotation of the differing plates is 0.8% (if 0.8% is correct). 0.8% of 360 degrees = 2.88 degrees. 2.88 x rear diff (3.214) = 9.256 degrees turn of the vcu, for every turn of the road wheels. Or approx 1 in 39. Assuming my maths is correct.

If removing just 1 prop you can get the fluid to move to the bottom of the vcu which sort of puts it out of balance when it spins, as the plates move at the same speed when only 1 prop is connected. It does flow round to even out due to centrafugal force, but that takes longer when not mixing. If the fluid is crap then I guess it wouldn't fall in the first place when stationary.

SamA90 · Oct 1, 2015

Hippo said:
0.8% of 360 degrees = 2.88 degrees. 2.88 x rear diff (3.214) = 9.256 degrees turn of the vcu, for every turn of the road wheels. Or approx 1 in 39. Assuming my maths is correct.

so...if my wheels are 92cm in diameter, that makes the circumference 2.89m...the VCU should rotate every 113m. And presumably after 1 rotation, the liquid should be well dsitributed...

davidsmith1307 said:
In which case it would be good to try taking it off and putting it back on in the 'same' position. This might tell us whether the tolerance on the holes is enough to cause a problem.
Then it would be a score draw between us and @jamesmartin and I'd take that any day!

I'll let you know how I get ont! So to clarify, I should seperate the front prop from the IRD, rotate the front prop 90degs, then reattach...right?

davidsmith1307 · Oct 1, 2015

That's the thinking. And try to make sure the prop is 'even' on the bolts, not slumped down onto the lower ones and thus slightly off-center.

GrumpyGel · Oct 1, 2015

My IRD has had a gear driving the rear pinion removed now for 2 years making it 2WD. So for 2 years the rear wheels and VCU have been dragging the front prop around. A result of this is that the VCU is as 'siezed' as you are likely to find one - I jammed the front prop, did a 1 wheel up test and the wheel would not move even with me pushing on the bar. I don't get any vibration when driving. I never take it up to fast Euro speeds as our limit here is 100kmh (60mph), but I'll regularly be up to 65mph within a couple of Kms of starting in the morning at sometimes -5 to -10 degrees when I'm in the 'high country'.

jamesmartin · Oct 1, 2015

Hippo said:
They're not poorly fitted. The rear prop connects to the rear diff with 4 bolts. The front porp connects to the pinion with 6 bolts. Each bolt hole has a slight tollerence or you'd never get the bolt through the hole. It's only out by a slight amount, but enough to only show at high speed when a spinning force is greater. An eggsample:

https://www.landyzone.co.uk/land-rover/vibrating-through-seat.273888/

and the result:
https://www.landyzone.co.uk/land-rover/update-vibrating-through-seat.274717/

We're not saying it fixes all rumbles, just some of them where every other option has been tried and the rumble is only at high speed.

very unlikely,nothing to do with the bolt tolerances, your doing something else if removing prop and refitting is having any effect

Hippo · Oct 1, 2015

jamesmartin said:
very unlikely,nothing to do with the bolt tolerances, your doing something else if removing prop and refitting is having any effect

step 1 take prop oft
step 2 put prop back
vehicle hasn't moved
where else is the tolerance when nothing other than remove/fit has happened?
it may defy some peoples logic but if it works it makes the owner and their Freelander happy
if peeps want to try it having tried everything else, there's no harm in trying what's helped others.

Alibro · Oct 2, 2015

Have you tried rotating the damper one hole?
Made a big difference To mine.

tacr2man · Oct 2, 2015

What condition are your rear diff mountings ? these can cause a cyclic rumbling vibration !

SamA90 · Oct 3, 2015

Update!
Props off. Didn't bother with the 90* rotation, because it was blatantly obvious that the bearing on the fore end on the VCU was shot to pieces.
It's only 3 weeks old. Also going to take my front prop to a specialist, as the front part (not sure what the term for it is) with the gator seems very loose and strange.

jamesmartin · Oct 3, 2015

SamA90 said:
Update!
Props off. Didn't bother with the 90* rotation, because it was blatantly obvious that the bearing on the fore end on the VCU was shot to pieces.
It's only 3 weeks old. Also going to take my front prop to a specialist, as the front part (not sure what the term for it is) with the gator seems very loose and strange.

its called a cv ( constant velocity joint)it should feel floppy but have no rotational play between its outer and the prop shaft

SamA90 · Oct 3, 2015

jamesmartin said:
its called a cv ( constant velocity joint)it should feel floppy but have no rotational play between its outer and the prop shaft

Thanks James. I'll get a video of it later on, it doesn't seem right to me. But then, over the last few weeks, I've learnt that a lot of things that I think are weird are perfectly normal!

SamA90 · Oct 3, 2015

Here is my knackered bearing and almost certainly knackered CV joint

Tiny1000 · Oct 3, 2015

The end comes of the CV joint, to me it looks like the little circlip that holds on the 3 bearings has come off. If so just pop it back on at the most you'll just need a new circlip for that end

SamA90 · Oct 3, 2015

Tiny1000 said:
The end comes of the CV joint, to me it looks like the little circlip that holds on the 3 bearings has come off. If so just pop it back on at the most you'll just need a new circlip for that end

I can't seem to get the CV away from the shaft...how do you get it off?
Wammer job?

Hippo · Oct 3, 2015

You should be able to lever the ends oft the cylinder bit that slides on the end. Some more pic's over ere:

https://www.landyzone.co.uk/land-rover/prop-sorted.162093/

SamA90 · Oct 3, 2015

Thanks hippo, got it off now...not really sure what I'm looking for

tonytherunner · Oct 3, 2015

With this http://www.ebay.com/itm/4-pc-Gear-P...ring-bearing-race-pull-tool-set-/270809046457

Tiny1000 · Oct 3, 2015

Well that looks ok, you sure you didn't pull it too far e.g. pulling the triple bearing out of the cup

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