VCU Torque test results

deangermouse · Mar 7, 2015

I have just fitted a brand new gkn vcu with bearings, run in for 100miles, outside temp 10 deg C. 5kg weight on 1.2 m length average time from 45 deg to horizontal 1 min 15 secs. I know there are lots of questions but if in doubt replace the vcu for peace of mind.

Arctic2 · Mar 7, 2015

deangermouse said:
I have just fitted a brand new gkn vcu with bearings, run in for 100miles, outside temp 10 deg C. 5kg weight on 1.2 m length average time from 45 deg to horizontal 1 min 15 secs. I know there are lots of questions but if in doubt replace the vcu for peace of mind.

Hi would you be so kind as to inform us where you sourced the GKN VCU from please, and cost I had the support mounts done today on mine, still getting some judder though so could be VCU yet to make sure over the next few days.

Hippo · Mar 9, 2015

Ere's some photo's of a broke'd Freelander ird (intermediate reduction drive). Think of it as a fixed ratio transfer box which takes the drive from the gearbox and passes it to the front wheels via a diff, and also to the rear wheels via the pinion gear.

Unfortunately this one has failed. There's a chip in the larger gear and the case has cracked when the gears were forced apart. Normally caused by too much stress in the transmission. More often than not caused by a vcu (viscous coupling unit) being too tight or the tyres not being the same make/model/size. This one is oft a v6 Freelander which sadly is no longer on the road.

The ird is pictured upside down. When fitted to a Freelander the damage would be on the side closer to the ground.

deangermouse · Mar 9, 2015

Hi, my new vcu came from autopost in london, although I didn't purchase it myself, I know that if you don't line the prop shaft, vcu shaft, bearings etc dead in line you can get a vibration judder. Hope this helps

Arctic2 · Mar 9, 2015

deangermouse said:
Hi, my new vcu came from autopost in london, although I didn't purchase it myself, I know that if you don't line the prop shaft, vcu shaft, bearings etc dead in line you can get a vibration judder. Hope this helps

Hi deangermouse.

I had the VCU support mounts fitted for me by bellengineering, therefore I would presume that all the prop shaft would be inline, prevous to that I have fitted rear new mounts on the diff, front lower engine tie rod, having had a good talk and a drive out together with hippo the weekend, we seem to think it may be the rear brakes causing the judder on braking from speed, because if you slow the car down using the throttle bring the speed to a minimum before you need to stop and not leaving it to late on braking the judder is only faint.

When turning left or right sharp forward or reverse there is no juddering or the FL trying to stall, a bit more investigation is required later this week when I hope to remove the rear shaft get the FL down to my local mot station and get the front and rear brakes on the rolling road.

I do have all new rear shoes, cables springs etc and have fitted new drums already but will wait until the rolling road test before fitting as then I know for sure one way or the other that the rear brakes can be eliminated from the situation, I will get to the bottom of it as I never let anything beat me

Arctic2

austen · Mar 9, 2015

The prop shouldn't be in a straight line, you cannot run/design a prop without the uj's having an angle otherwise it caus3d massive vibrations.

deangermouse · Mar 9, 2015

Sorry I meant the vcu shaft and bearings, the fitter said it was very important to get them aligned to eliminate bearing wear, vibration etc, but surely the straighter the prop shaft the smoother the drive? Uj's or not, straight would be smooth?

Arctic2 · Mar 9, 2015

austen said:
The prop shouldn't be in a straight line, you cannot run/design a prop without the uj's having an angle otherwise it caus3d massive vibrations.

deangermouse said:
Sorry I meant the vcu shaft and bearings, the fitter said it was very important to get them aligned to eliminate bearing wear, vibration etc, but surely the straighter the prop shaft the smoother the drive? Uj's or not, straight would be smooth?

Austin
As above I think deangermouse is referring to the white lines which were painted on my VCU and shaft which I think you saw when you fitted the good VCU mounts, they were from the previous owner having a prop shaft fitted but only had one support mount fitted instead of two

and that was of poor quality from what I/we saw when it came off.

Austin I also felt the VCU as you suggested when got home from yours and it only felt luke warm to touch, as I say hopefully I will know a lot more towards the weekend when I have had time to investigate further,
I must say though that is a neat trick how you remove the VCU :clap2: and refit it

Arctic2

Hippo · Mar 9, 2015

The props on a Freelander 1 look like this when fitted correctly:

The vcu with it's bearings will look like this (from the rave disk)

austen · Mar 9, 2015

90degs ish is fine as the rubber takes up any slight misalignment. Remember the engine and ird are constantly moving in relationship to the fixed vcu.

All prop UJ'S (all cars not just freelanders) have to be run a slight angle otherwise you can get concentric vibration, as a rule of thumb they can be run up to 7 degs off parallel.

My guess is going to be brakes or a worn UJ, but worn uj's or prop cv but usually show up under power not braking. Your VCU was not in good shape either so when it's changed you may find it runs smoother.

The temp comment is only proof about your tyres being matched not a stiff vcu (yes extremely tight ones can get hot, but it's not a conclusive test)

austen · Mar 9, 2015

The white lines on the vcu and prop don't do anything as the vcu slips the front and rear relationships change.

Hippo · Mar 9, 2015

austen said:
The white lines on the vcu and prop don't do anything as the vcu slips the front and rear relationships change.

It's agreed the vcu alters across itself but some on ere have had vibration at high speed only. It's as if something is only slightly out, which requires speed to detect. There was a chap on ere about a month ago with this problem. The solution was put forward to turn one prop by 90 or 180 degrees and see how it went. The usual discussions (arguments) were had and the result was it solved his high end vibration. This is a trick which we have found to work many a time.

austen · Mar 9, 2015

It'd probably down to worn uj's and disturbing them, the vcu slips 1 revolution every second at 60mph do matching the front to rear disappears within a few yards of driving it.

Hippo · Mar 9, 2015

austen said:
It'd probably down to worn uj's and disturbing them, the vcu slips 1 revolution every second at 60mph do matching the front to rear disappears within a few yards of driving it.

But what if the balance of the rear prop to rear diff is out? If you imagine they're spinning together and not in perfect alignment. These strange vibrations at 40/50+ only need to be slightly out.

I've seen props that roll with no uj or end bit fitted. Also some where they're very slightly bent. Going oft road and handing on the prop is easy to do but unfortunate. Also one chap cut his prop in half in anger and it contained mud which we assume dried on one side after he'd been oft road then parked up over night. There are all rarities but cured the same way.

krisboats · Mar 11, 2015

I've just done the 1.2m with 5kg weight and it took roughly 45-50 seconds to rotate through 45 degrees to horizontal.

The car was driven about 5 miles 2 hours before the test and was cold to the touch when test was conducted.

Whats the verdict?

krisboats · Mar 11, 2015

So i did a couple more tests throughout the day/evening. Final one has it coming in at around 58-62 seconds to do the 45 degrees. so i presume it's cooled down a fair amount by then.

htr · Apr 17, 2015

Well I did a series of one wheel up tests, five essentially when cold, I had driven about 2km and none over 50kmh and it had sat for about 45 minutes. I did another five after driving the course I did yesterday 19km or so.

Weather, high overcast, some light rain showers, very little wind and about 12ºC.

I used a 1255mm piece of square aluminium tube as my bar, a 32mm socket, my 1/2" ratchet drive and 3 plastic bottles with just under 8L of water. I put a screw in at the 1200mm point to hang the bottles on.

Timed from the 45º mark to horizontal rest [90º]

FL1 K series 1.8 190,000km, original VCU. All transmission oils have now been replaced. This FL has had a s/h IRD fitted at some point in the past.

Results - COLD
#1 - 2.00
#1 - 2.02
#2 - 2.08
#3 - 2.09
#4 - 2.00

Averages out at 2.03 rounded.

Results - Warm
#1 - 1.29
#2 - 1.35
#3 - 1.41
#4 - 1.46
#5 - 1.51

Averages out at 1.40.

Interesting in the second set of tests the time got longer as the VCU cooled.

Apologies for posting again. I've made a thread of this already should have plonked it here.

Alibro · Apr 20, 2015

austen said:
It'd probably down to worn uj's and disturbing them, the vcu slips 1 revolution every second at 60mph do matching the front to rear disappears within a few yards of driving it.

Is it possible the propshaft is matched to the IRD and balanced, or it may need to be running for a time to bed everything in then loosening and re-tightening at the IRD might be enough to sort any balance issues.

Anyway I hope to have my DIY VCU fitted in the next week or so and will report back.

jedi · Apr 23, 2015

austen said:
the vcu slips 1 revolution every second at 60mph.

Are you sure about this? Surely that can't be right?

It would take a huge amount of force to keep turning it 1 rev a sec? At that speed it would lock up surley?

Hippo · Apr 26, 2015

jedi said:
Are you sure about this? Surely that can't be right?

It would take a huge amount of force to keep turning it 1 rev a sec? At that speed it would lock up surely?

1 rev of the rear prop per second drives the FL1 at 1.496mph approx.

That's assuming:
tyre circumference is 2.15meters
rear diff ratio is 45/14
FL1 driven in a straight line with perfectly matched tyres

60mph turns the rear prop at 40 revs per second approx.

VCU Torque test results

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