The Mad Hat Man

The Mad Hat Man

Well-Known Member
LZIR Despatch Agent
Austen

As you well know, there have been many and varied attempts to try and ascertain a repeatable and significant test to perform on Freelander VCU's. You have answered many questions on VCU performance and have posted on youtube, the test that you carry out on VCUs sent to you for refurbish (and presumably after rebuild).

What I am asking here is for you to supply data from your tests. I do not believe that you conduct a torque test; or at least you do not measure "Torque" using absolute values, but by an empirical method, such as a weight on a bar and monitor the rate of fall of that bar.

Whatever tests you carry out, you must have some form of "value judgement" as to whether a VCU under test is "good", "bad", "acceptable" or possibly "beyond repair".
I am not asking you to give away Business sensitive information here, but give some guidance to assist in formulating a test that can be carried out by an owner.
You are in an ideal position to do that.

The ball is now in your court...... will you help or not?
 
I'm watching this with interest but please excuse my ignorance. Can you explain a VCU, vacuum control unit perhaps ? I am keen to learn. Thanks.
 
The Mad Hat Man said:
Austen

As you well know, there have been many and varied attempts to try and ascertain a repeatable and significant test to perform on Freelander VCU's. You have answered many questions on VCU performance and have posted on youtube, the test that you carry out on VCUs sent to you for refurbish (and presumably after rebuild).

What I am asking here is for you to supply data from your tests. I do not believe that you conduct a torque test; or at least you do not measure "Torque" using absolute values, but by an empirical method, such as a weight on a bar and monitor the rate of fall of that bar.

Whatever tests you carry out, you must have some form of "value judgement" as to whether a VCU under test is "good", "bad", "acceptable" or possibly "beyond repair".
I am not asking you to give away Business sensitive information here, but give some guidance to assist in formulating a test that can be carried out by an owner.
You are in an ideal position to do that.

The ball is now in your court...... will you help or not?
Click to expand...


Fair question, come on Austen - help us out with some info on how we can check this. It might end up getting you more business from folk here who use your test & find their units marginal.
 
I have not bothered doing the test listed on here after reading on his site that basicly it was bollocks! Mine is on 87,000 miles but seems ok. It was when I went up an extremely steep rocky surface. Probably not a reliable way of telling though. Although it told me it wasn't just in 2wd.
So yes a definitive guide to testing would be good.
 
Narfalk N good said:
I have not bothered doing the test listed on here after reading on his site that basicly it was bollocks! Mine is on 87,000 miles but seems ok. It was when I went up an extremely steep rocky surface. Probably not a reliable way of telling though. Although it told me it wasn't just in 2wd.
So yes a definitive guide to testing would be good.
Click to expand...
It may be considered bollocks, and many others on ere have the same opinion, but it’s the only test we have to date which someone can do at home, to test their vcu, on a diy basis. If you read MHM’s thread on vcu’s, you’ll appreciate the test for what it is, and what it tells you. It’s not a sure fired conclusion to the condition of your vcu, but it does give you a reference which you can compare to others. Some have done the test and found their vcu is seized. Look up the price of a replacement ird or/and a rear diff, and you’ll realise how helpful the test can be. If a betterer way to test the vcu by the owner, on a diy basis comes along, then we will of course use that instead.
 
isnt the fact you can turn it good enough to let you know ,we used to do the borgwarners for lr and there wasnt a specified torque test for viscous just feel ,they sent a bloke to show us ,they varied alot (new ones )depending on temp to ,but there was a definate feel used ones)to poor or failing one apart from seized in that it didnt feel smooth,do you have a link to whoever austin is
 
Narfalk N good said:
I have not bothered doing the test listed on here after reading on his site that basicly it was bollocks! Mine is on 87,000 miles but seems ok. It was when I went up an extremely steep rocky surface. Probably not a reliable way of telling though. Although it told me it wasn't just in 2wd.
So yes a definitive guide to testing would be good.
Click to expand...


Which one of the tests did you not do, as there are several tests suggested on here. One of which is by Austens company :rolleyes:.
As Hippo says - We know the test(s) are not above criticism, but at the mo they are they best that anyone has got. The only other options seems to be replace the VCU without regard to its condition or to run until you recognise the symptoms of a failing VCU, with prospective expensive repairs.

Which do you want to do?
 
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jamesmartin said:
hello
Click to expand...
Shorry, got loads of xp updates coming through.
jamesmartin said:
isnt the fact you can turn it good enough to let you know ,we used to do the borgwarners for lr and there wasn’t a specified torque test for viscous just feel ,they sent a bloke to show us ,they varied alot (new ones )depending on temp to ,but there was a definite feel used ones)to poor or failing one apart from seized in that it didn’t feel smooth, do you have a link to whoever austin is
Click to expand...
Yes seeing it turning is good, but by how fast compared to the strength required to turn it, is a betterer indicator. We is hoping there is a gradual change in the sheering effect (slippage of the plates in side) which changes as the vcu degrades in some way. Hence as per my video below, if someone were to do the exact same test, same weight/bar length, and it took 5 times longer to turn the same amount, you'd think the vcu was closer to becoming seized, than mine is. A visual aid, but not scientific proof.
 
jamesmartin said:
didnt you get average on test i think were been done christmas time
Click to expand...
There was a number of people who did the test, and put up results, but not as many as we would have liked, to get a wider spectrum of figures. Hence this letter post to Austin for help.
 
Hi just seen this.

If we are going to do this properly then lets agree how you want to test the VCU, i.e. on or off the car. We test all ours off the car as it obviously how we receive them, plus its just easier. I personally would rather have a test quantified with the units removed, its more controllable and a lot easier to knock a controllable rig up, but i do appreciate that owners want an easy option.

Rather than measuring torque, which without a controlled machine, and calibrated torque wrench is very inaccurate, we measure by "feel", We can say if its acceptable, not acceptable or on the verge, its impossible to give a definitive pass or fail. The VCU slowly deteriorates so you have to weigh up the cost to change vcu and the extra wear you are causing to the drive train as time goes by. When we supply an IRD we test the customers VCU and make a call based on our judgement on weather or not the VCU is in good enough condition to be refitted, our warranty is based on that decision, if the VCU is deemed to stiff and the customer will not change it we will not warranty the box.

Sorry i digress!!! Ok so how do you want the test performed? If its has to be on a car i may need a volunteer to come over as the only freelander we have now has no rear drive train in it, yeah yeah i know we should replace it, but its our car and bus mans holiday and all that!! ;)
 
jamesmartin said:
isnt the fact you can turn it good enough to let you know ,we used to do the borgwarners for lr and there wasnt a specified torque test for viscous just feel ,they sent a bloke to show us ,they varied alot (new ones )depending on temp to ,but there was a definate feel used ones)to poor or failing one apart from seized in that it didnt feel smooth,do you have a link to whoever austin is
Click to expand...

Interesting that you say that the torque! required varies with temperature as the "hysteresis" curve of the silicone fluid (in the vcu test Fred) shows a flat response up to above 100C and then a sudden change within 10 or so degrees. If it varies a lot at ambient temperatures, that cannot be a good thing, Shirley?

The more I find out about these things, the more I think they are ****e!
 
A VCU should never be at 100degs in normal operation. They should be luke warm at most, ideally cold to the touch. If they are warm or hot you have mismatched tyres or been off roading or driving round and round in circles. I fitted a unit on monday night to car and when he arrived VCU was warm, probably just about acceptable, but as he had come all the way from cornwall i swapped the front and rear wheels over as there was about 5mm difference in diameter, this should mean the recon vcu will run cold.

The viscosity of the fluid in our barrel does change with ambient temperature, but it has to be extreme to really see a difference, infact in the very cold weather this winter it went thicker, yes i know this isn't what you expect, but in real operating conditions, small amount of slippage, it sort of keeps it at a constant (low) temperature

IMO, The heat cycles are what kills VCU's.

Oh just to add, a very tight VCU will get warm-hot even with matched tyres
 
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The Mad Hat Man said:
The more I find out about these things, the more I think they are ****e!
Click to expand...

They are used in more cars than you think. The more modern Haldex units work on exactly the same principle, but the amount of fluid/pressure, and hence amount of drive transmitted, is altered electronically. These are fitted to nearly every 4x4 (VAG, Volvos, Freelander) car on the market now.
 
Thanks for your reply, Austen.
I understand why yu test off the car, but I think most peeps would want to test it in situ, particularly those without a good mechanical aptitude. The most that could be expected would be the removal of the rear prop, if that is relatively easy.
The easiest test is via the rear wheel, but I accept that that would include other transmission tightness (leaving the handbrake on. :doh:).

I think the problem that I have is understanding that if the VCU imposes more and more strain on the transmission as it "stiffens up" as it surely does, then I fail to comprehend how this "stiffening" cannot be quantified.
I understand that if you work with them then you get a "feel" for them. It's how to enable the untrained to get that same "feel".
As stated before, if a reasonably reliable test can be found, then more peeps will conduct that test and you will gain both business and kudos from that. OK - yu may get less IRD work, but that isn't ( recent other thread) necessarily a bad thing.

Once again we do appreciate your help, as you are in a pretty unique position to do so. Hopefully the promotion of your company by members on here is also of value to you?
 
So how about a breaker bar on the hub nut, a known length of bar and known weight, and a video of a good (recon) VCU, fecked VCU, and if i can find one in the pile "on the verge" VCU?????

Obviously this will take a bit of time to perform, and we will need a Guinea pig car. I cant really use a customers as they wait while i fit them, not sure they wpuld be happy for me to fit 3 while they wait ;)
 
Just to add, i've never tried doing it this way, and just wonder how things maybe affected by the leverage caused by the diff, i.e. it will take approx 3 times the amount of force to rotate the VCU through the diff than directly on the splines
 
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