zippo105

viscous coupling new info

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just brought a new viscous coupling which has zero braking on full lock and the freelander 18 new drives like a brand new one

the viscous is a recon which has been reconditioned to be :loose: no more bad tyre were problems.the unit i took off was not seized

but was starting to feel tight.the price of the new one was £225+vat and only £5.00 postage (nextday) it came from david beaumont 4x4 gearbox specialist

in halifax. telephone number 01422 244587 .as i said mine was tight when on full lock and felt like the brakes were coming on a bit now its totally free.also

i did the 'tippex test on the old one and the dots did move apart.the back wheel was notchey and hard to turn .but now with the new recon unit it is quite easy to

turn by hand useing just the tyre jacked up.so heres to the next 50.000 miles.the old viscous had done 52000 mile and was just getting tight.not gonna risk the ird or dif so got a recon

that has now made the freelander feel like a new 4x4 again

hope this helps anyone with doubts about there viscous

dave

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just brought a new viscous coupling which has zero braking on full lock and the freelander 18 new drives like a brand new one

the viscous is a recon which has been reconditioned to be :loose: no more bad tyre were problems.the unit i took off was not seized

but was starting to feel tight.the price of the new one was £225+vat and only £5.00 postage (nextday) it came from david beaumont 4x4 gearbox specialist

in halifax. telephone number 01422 244587 .as i said mine was tight when on full lock and felt like the brakes were coming on a bit now its totally free.also

i did the 'tippex test on the old one and the dots did move apart.the back wheel was notchey and hard to turn .but now with the new recon unit it is quite easy to

turn by hand useing just the tyre jacked up.so heres to the next 50.000 miles.the old viscous had done 52000 mile and was just getting tight.not gonna risk the ird or dif so got a recon

that has now made the freelander feel like a new 4x4 again

hope this helps anyone with doubts about there viscous

dave

Good news, Dave!

Myself I am looking for a "loose" VCU but I have not been able to source one. How does the new unit work at serious 4x4 work? Did you have to return your old VCU in exhange?

I wonder whether the reconditoned unit just has had the silicone jelly replaced with a thinner fluid or it has been totally stripped and re-welded and filled with fresh jelly.

Did you notice what the filling/bleeding points on each side of the VCU drum look like? Are they pressed-in steel balls (approx. 4mm dia.) or threaded-in plugs?

Jon, Norway

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Good news, Dave!

Myself I am looking for a "loose" VCU but I have not been able to source one. How does the new unit work at serious 4x4 work? Did you have to return your old VCU in exhange?

I wonder whether the reconditoned unit just has had the silicone jelly replaced with a thinner fluid or it has been totally stripped and re-welded and filled with fresh jelly.

Did you notice what the filling/bleeding points on each side of the VCU drum look like? Are they pressed-in steel balls (approx. 4mm dia.) or threaded-in plugs?

Jon, Norway

[/quote

it works ok off road .i was told if towing .ie.a caravan on mud and got stuck the back wheels may not turn/grip with the extra wieght bearing down on it. but in general off roading is ok.

tried it out on a muddy steep slope and all 4 wheels keep turning..the unit has a hex key plug in it approx 4/6 mm.the old unit has to go back but never had a deposit on it.the main thing to me was to

find a"loose" vcu.the web address is http://www.4x4gearboxes.co.uk/ look in land rover/freelander and theres a piece on vcu.

hope this helps.

dave

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Thank you for the link, Dave. I have sent them a mail and asked for a quote on a VCU similar to yours.

I am afraid the shipping will be expensive, so maybe I should try to do a fluid refill myself.

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hi,,a friend of mine is having probs with his viscous coupling,,hes removed it,and wants to know how to test it,as its a new one,could you tell me how the tippex test is done?,,thanks very much,,wayne.

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hi,,a friend of mine is having probs with his viscous coupling,,hes removed it,and wants to know how to test it,as its a new one,could you tell me how the tippex test is done?,,thanks very much,,wayne.

the tippex test is done by putting a dot on each prop in the same place and on the viscous in a line.then drive a figure of 8 full lock backwards.the dots should go out of line if the dots are in the same place then the chances are its siezed.if the freelander feels like its brakeing when on full lock backwards ie like the handbrakes half on then its probally getting tight.the original vcu,s did feel a bit tight that was normal.ie you should be able to do a full lock u turn backwards on tickover. without stalling or excessive engine drag at tickover with clutch right up.the vcu is a form of fluid clutch and allows slip so no damage is done to the ird of diff from excessive strain so both props can move at diffrant speeds.but if front wheels/prop spin faster than rear then vcu heats up and locks both props to give solid 4 wheel drive and as it cools it lets the slip come back.

hope this helps

dave

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the tippex test is done by putting a dot on each prop in the same place and on the viscous in a line.then drive a figure of 8 full lock backwards.the dots should go out of line if the dots are in the same place then the chances are its siezed.if the freelander feels like its brakeing when on full lock backwards ie like the handbrakes half on then its probally getting tight.the original vcu,s did feel a bit tight that was normal.ie you should be able to do a full lock u turn backwards on tickover. without stalling or excessive engine drag at tickover with clutch right up.the vcu is a form of fluid clutch and allows slip so no damage is done to the ird of diff from excessive strain so both props can move at diffrant speeds.but if front wheels/prop spin faster than rear then vcu heats up and locks both props to give solid 4 wheel drive and as it cools it lets the slip come back.

hope this helps

dave

thanks loads mate,,thats great,will let him know,,cheers,wayne. ;)

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the best test for the VCU is to chock the front wheels front and rear , lift one of the rear wheels,pop the centre cap on the wheelfit a socket and long breaker bar on the hub nut release the handbrake, engage first gear then try to rotate the raised wheel, if you can then the VCU is ok.

i think the driving in a tight turn is subjective, one mans tightening up is another mans ok

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one mans tightening up is another mans ok.yer its ok to say that but i used a breakers bar and the vcu turned.then i reversed into a parking space on full lock on tarmac and one back wheel kept scuffing heavy.now i have new loose recon vcu its like a new car very smooth.why risk the ird and diff .is there any test which is 100%. my advice is just from personal experence.but now i have a very smooth freelander with 4 wheel drive that works spot on.and dont scuff its tyres away.its also vibration free at all speeds.the point of this tread is to tell peaple of the way i did it.and how the new vcu has worked.

dave <_<

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I've done a lot of reading up on viscous couplings recently:

VW used them to drive the front wheels of their "synchro" vans. They have many of the same issues with tyres etc as Land Rover Freelander VCUs. VW Viscous couplings can leak (not a problem for LR VCUs) causing no drive to front wheels, or gellation of the fluid causing constant drive (as with LR).

From: http://www.syncro.org/VCTest.html

There appear to be two primary causes for the VC to engage when it should not: (1) having tires that are not all the same size and wear (all 4 must be the same), and (2) age...VCs appear to have a nautural life span, at least where subjected to routine high operating temps.

Also, I would wager the below (form the link above) is the primary reason for LR Freelander VCU failure, especially as the early vehicles gearing meant the unit was constantly slipping and hence heating the fluid:

A typical scenario leading to a cooked VC would involve a syncro with tire sizes that vary slightly in treaddepth. The syncro is regularly driven at highway speeds for hours at a time over a period of time. Eventually, the driver notices binding in the drive train whenever she pulls off the highway into a gas station for gas. It may be subtle at first. Eventually, though, as the fluid gets cooked and ruined, the wheels seem to stiffen or bind much easier than before, and ultimately at the slightest turn of the wheel. When it gets bad, the drive train may lock up completely in the parking lot at very slow speed upon a relatively slight turn of the steering wheel. This total engagement of the drive train puts tremendous strain on the components of the drive train when the van is moving at speed under power. With continued use, the transaxle soon fails, the drive shaft and CV joints are also strained.

See also: http://www.vanagon.com/syncros/technica/ for some more info.

It would appear Land Rover VCUs (like VW) suffer from "Gellation" where the fluid spoils and goes thick, causing transmission wind up (perhaps due to the unit constantly accounting for the mis match in gearing). So even if a car passes the "VCU test" of jacking up and turning a rear wheel, the fluid may still have spoilt to a certain degree and be causing a load up of the Diff and IRD - i.e. its not totally solid but is dragging.

I suppose the test should be changed to "if the rear wheel is hard to turn" - you would need to compare a new VCU to yours to tell - if yours is harder to turn then the new VCU it might be on its way out. But I would like to see other evidence like wear patterns on tyres and the reverse skipping tyre test. I would say going by the expense of new IRD and diffs then prevention by fitting a new VCU to a car that has the reversing issue and scrubbing rear tyres would be wise.

This does negate the common belief that if a Freelander is used off road a lot then the VCU will be healthier - unless of course regular "cycling" of the fluid helps keep it in good condition, but I do not know enough of the chemical composition and properties of the fluid to comment on this.

This link indicates it is possible to refurbish a VCU: http://www.vanagon.com/syncros/technica/vc-expert-interview/index.html You can imagine drilling out the fill points on the VCU, blowing the fluid out with an airline, fitting brake nipples or similar and refilling with fluid. However it seems the sticking point would be locating a supplier of the correct fluid! We have no idea of the exact composition of the fluid Land Rover used.

These guys refurb them and sell for £200 - they must get their fluid from somewhere - but £200 seems pretty reasonable if they have a warranty:

http://www.bellengineering.co.uk/5.html

Hope this info helps people understand the VCU!

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yep thats the point i was makeing.as with mine change it if in any doubt.as alot of the recon ones are made "loose" ie poss thinner fluid the freelander then has even less strain on it.and is a fraction of the price of a ird and diff when its to late(nice piece of input to the thread)

dave

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yep thats the point i was makeing.as with mine change it if in any doubt.as alot of the recon ones are made "loose" ie poss thinner fluid the freelander then has even less strain on it.and is a fraction of the price of a ird and diff when its to late(nice piece of input to the thread)

dave

I have heard nothing from Beaumont yet but I think I may have found the fluid to fill my old VCU with. I have ordered two different grades of the stuff and I hope the thinner one may give a looser engagement.

Getting the plugs(they are bearing balls actually)out was tricky but I made it finally. In a few day when I get my fluids I will know how it works.

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I have heard nothing from Beaumont yet but I think I may have found the fluid to fill my old VCU with. I have ordered two different grades of the stuff and I hope the thinner one may give a looser engagement.

Getting the plugs(they are bearing balls actually)out was tricky but I made it finally. In a few day when I get my fluids I will know how it works.

how thick is the old fluid which comes out and does it get thinner if it gets colder.coz the plug is very small.or can it be forced thou from other side ie compressed air .how did you get old fluid out.it seems that my new one has larger holes and larger plugs.poss to get old fluid out easy?.will be interesting to hear your results

thanks

dave

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jonaf

any progress with renewing the fluid in your VCU? If so any chance of an update? especially the procedure you followed i might do this to my truck if its not exorbitantly expensive,

cheers

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jonaf

any progress with renewing the fluid in your VCU? If so any chance of an update? especially the procedure you followed i might do this to my truck if its not exorbitantly expensive,

cheers

I had no success getting the old gel out with compressed air. However I have pressed fresh silicone fluid with a vicosity of 12500CS into the unit to dilute the old thick gel. I threaded grease nipples into the VCU and pressed the fluid in with a grease gun. The unit is now easier to twist so I am going to put it back and try it out soon.

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jonaf

i expect you have already thought of it, but, does warming up the VCU increase the viscosity of the gel letting it flow easier? keep us posted please very interested in this

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jonaf

i expect you have already thought of it, but, does warming up the VCU increase the viscosity of the gel letting it flow easier? keep us posted please very interested in this

I experimented both with heating and cooling the VCU. First i put it on the stove and heated it to more than 50 deg C, put it in the vice and torque tested it. Then i put it outside in the snow for a couple of hours and did the same test. I think it was a little easier to twist when it was hot but the difference is hard to tell. Taking exact torque measurements i not easy because the torque increases when force is applied.

A mate bought a new VCU and when I gave him a hand with fitting the bearings I also took the opportunity to assess the twisting force. I think the one I now have put fresh silicone into is pretty much like a new item, maybe a little softer.

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jonaf

thanks all input would be appreciated,reelanders i think most of us dri

ving ten year old Freelanders just wait for the next thing to fail :(

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Today I spoke to Mrs Beaumont @ David Beaumont Gearbox specialists she said much the same as has been quoted on this thread about it being filled with a "thinner " gel thus causing less stress on the IRD and was quite honest to suggest a OEM item would be better if serious offroading and caravan towing was required.

I'm over in SW Ireland and when I asked if it was exchange she said that because of the distance it wouldn't be required. A very reasonable carriege price of £30 was quoted.

I also asked if they could supply OEM VCU / prop bearings and she said no and advised me to go OEM.

I was quite impressed with her answers.

Whats the concencus of opinion on these "loose " VCU's ? It's for my wifes FL 1 1.8 K series it's never off road and only used as a day to day road car.

On the subject of OEM VCU bearings I priced a couple from my local LR Main Dealer € 111 each (£97 ) !!!!!!

Can anyone tell me how that compares with UK list price ?

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jonaf

thanks all input would be appreciated,reelanders i think most of us dri

ving ten year old Freelanders just wait for the next thing to fail :(

I fitted the propshaft and VCU today and everything works fine. I have no binding when reversing with full steering lock, still the 4WD works OK in the snow.

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I've just had a re-con viscous from Beaumonts delivered.

I won't be fitting it for a week or so yet as I have more pressing issues (engine on the bench at the mo!! :( ) but I was very impressed when I spoke to the laydeeee there. I particularly like the surchage policy... "we're down you way every now and then so keep hold of the old unit until we are next passing." :)

Will post up when the car is back on the road, but service-wise they have a thumbs up from me so far.

WDWN... you can get replacement VCU bearings for as little as £20... see here. May not be a good thing to use this company tho, I've heard they don't like sending stuff outside the UK.

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Today I spoke to Mrs Beaumont @ David Beaumont Gearbox specialists she said much the same as has been quoted on this thread about it being filled with a "thinner " gel thus causing less stress on the IRD and was quite honest to suggest a OEM item would be better if serious offroading and caravan towing was required.

I'm over in SW Ireland and when I asked if it was exchange she said that because of the distance it wouldn't be required. A very reasonable carriege price of £30 was quoted.

I also asked if they could supply OEM VCU / prop bearings and she said no and advised me to go OEM.

I was quite impressed with her answers.

Whats the concencus of opinion on these "loose " VCU's ? It's for my wifes FL 1 1.8 K series it's never off road and only used as a day to day road car.

On the subject of OEM VCU bearings I priced a couple from my local LR Main Dealer € 111 each (£97 ) !!!!!!

Can anyone tell me how that compares with UK list price ?

the bearings from david beaumont were £32 a pair and have bedded in ok on mine

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I've just been round in our sales office talking to some staff about various non-work related stuff ;) ... for some reason the conversation turned to custard :huh: At this point one of the employees mentioned that custard actually gets thicker when agitated. This got me thinking.... could it be used in a viscous??? :lol:

(I will not he held responsible for any damage caused by anyone attempting to replace the gel in their viscous coupling with custard!! :P:lol: )

Dan

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(I will not he held responsible for any damage caused by anyone attempting to replace the gel in their viscous coupling with custard!! :P:lol: )

I love it when you get all technical Dan :hysterical:

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Hi Jonaf

Good job that man :)

Where did you get your silicon fluid from? spec? and is there a specific way to lineing the VCU bearings up to the VCU/prop shafts?

Thanks in advance

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