Can someone please explain the mechanics of a VCU

Hi all. Could someone briefly explain the mechanics of a VCU. Only mine has siezed and im not sure if i need to replace the whole unit or just replace the damper. Is the VCU unit siezing caused by the damper its self or could it be another problem with the unit. Im running around in 2wd at the moment and would like to get back to 4wd while the weather is ****e and £70-£80 for a new damper is better than hundreds for a new unit.

Cheers, Mark

It is a fluid filled coupling. When the front wheels begin to slip, the fluid becomes kind of solid and engages the rear wheels and thus 4WD - very basic analogy!!

If your VCU is seized, then it needs to be replaced. Choose a good supplier and not second hand on ebay etc.

Regards,

Steve

Cheers for that G1. I will buy a recon unit. i cant believe people are paying over £150 for second hand units off ebay.

1st be very wary of recon units as there are many stories of problems with them. The damper has no functional purpose in terms of its operation. These units are very tight from new, on what basis do you think it is siezed? I posted a link to a video of somebody testing one on the vehicle and it quite surprising how much force is needed to turn one.
The reason for them becoming locked is primarily down to deterioration of the silicon gel fluid and is due to age. Far less common is a mechanical problem. A relatively frequent suggestion is that a vehicle that has never been used of road will suffer failure early but with the design of the transmission they are always working even when on tarmac so I am not sure.

Viscous coupling unit - Wikipedia, the free encyclopedia Excellent explanation here.

With pictures

Lochen said:

Viscous coupling unit - Wikipedia, the free encyclopedia Excellent explanation here.

With pictures

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except the bit about heat is wrong.
they will work instantly even in these freezing temperatures

Chaser said:

except the bit about heat is wrong.
they will work instantly even in these freezing temperatures

Click to expand...

Ta. I thought heat was what did it but it apears its 'shear', I guess heat is generated as a side effect.

I asked the very same question here the other night and the Mad Hat Man was good enough to answer but while we were chatting I found the wiki description.

How quickly does it disengage? or does it at all?

[smile] Yawn! [/smile]

Dont peeps ****in :search:any more? or do they need their arses wiped as well

The Mad Hat Man said:

[smile] Yawn! [/smile]

Dont peeps ****in :search:any more? or do they need their arses wiped as well

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Moi?

Non

Don't some people realise that some of us are Newbies, and search, or otherwise might be a bit harder for some of us technophobes etc. A simple question only requires answers whether that is boring to others or otherwise should be irrelevent !! i thought this was going to be a helpful forum or am i being too sensitive and in risk of being banned !!!!

Havent you heard of :googleit:?

just LOOK at this lot?


oh yes - sensitive - yup......... banned - most unlikely.

kawarex said:

Don't some people realise that some of us are Newbies, and search, or otherwise might be a bit harder for some of us technophobes etc. A simple question only requires answers whether that is boring to others or otherwise should be irrelevent !! i thought this was going to be a helpful forum or am i being too sensitive and in risk of being banned !!!!

Click to expand...

Searching for and reading a few posts on the same subject isn't a lot to ask of newbies and isn't difficult at all.

You need to understand that the people that contribute to this forum spend their time passing on plenty of helpful information and all that is asked in return is a little effort to find if the subject has been covered before to save them going through what can be a long explanation over and over again.

If you stick around, and many don't once they've had their free help, you will see how often certain questions are asked. You will also note that some don't even bother to post back with a thank you for the time that has been spent helping them.

I know it is US because i have all the signs of a siezed VCU (clunking when revearsing,feeling opf brakes binding when traveling slow, Metal particals in IRD oil) The reason i asked the question is because i was wondering if i could just change the damper and not the whole unit. I did look on wikipedia but the pictures shown do not depict a freelander VCU. If the question bothers you so much, WHY reply and waste your time.