DIY VCU service

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A VCU is a very simple contruction. Just a housing with two sets of rotating plates inside and filled with a fluid that thickens when the plates rotate in relation to each other. The thickness and amount of fluid determines the torque it takes to twist the unit.
I would not attempt to drill all the way through the ends of the VCU because the plates may be damaged. A diamant core drill for drilling ceramic tiles works OK to drill around the diameter the hardened steel balls that are used to plug the holes the VCU was filled through.
Once this is done and the holes are tapped to take grease nipples to fill through it is possible to experiment with the fluids to make VCU work the desired way. Thin fluid: soft coupling, thick fluid: stiff coupling.



 
VCU reconditioners don't drive Freelanders but are happy to quote to us their knowledge on VCU's and how Freelanders should drive. They take a guess on what to fill them with and the amount as they don't know either. Several on you tube have refilled their own VCU. From little acorns...
 
It's alright untill you sell the car and they send it in to be serviced and some numpty in the garage will fill it up with grease! Won't be your car by then though but I can see an accident waiting to happen in the future!
 
Oh, too marks for doing it yourself though! I wouldn't of wanted to play about with the vcu because it costs too much in time and money when it goes wrong
 
Excellent!!! work Jonaf:banana:.....This is what I like to see, The thickness of the VCU casing looks quite thick? :biggrin1: looking at the photos you have posted, How far in does it go, before your reach the plates inside?

What sort of fluid did you use to refill them?
 
Kizzeh said:
It's alright untill you sell the car and they send it in to be serviced and some numpty in the garage will fill it up with grease! Won't be your car by then though but I can see an accident waiting to happen in the future!
Click to expand...

Just like some numpty taking out the wrong drain plug on an auto box?:whoosh:

Filling it with grease will most likely make it slip more, more mondo mode:D

That's why I don't send my car to numpty garages, as you will get numpty`s working on it:banana::bump2:
 
jonaf said:
"Calibration" of the VCU is carried out this way with three wheels on the floor:
Click to expand...

I mean the same type as when you calibrate your wheels, due to off-centered weight of the grease nipple giving extra vibration on the VCU as it spins...

and you should torque the hub not the wheel nut.
 
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baptista said:
I mean the same type as when you calibrate your wheels, due to off-centered weight of the grease nipple giving extra vibration on the VCU as it spins...
Click to expand...

You mean "balance"? The VCU has a vibration damper bolted on to it because the fluid drops to the bottom of the unit when propeller shaft is not spinning.The grease nipples are also fitted 180 degrees apart so they cancel each other out.
 
don't get me wrong I am a big defender of DIY and knowledge share but I have to hit the brakes when somebody says that reconditioning a VCU is as easy as drilling two holes and greasing it up through a nipple. I'm not saying jonaf is doing it wrong just saying it has much more to it.

this is how it is done by some respected guys from a Portuguese LR forum, they have been doing it for a few years and with positive results and I guess they are doing it right since they have no negative feedback by other forum members that have used their reconditioned VCUs and they even guarantee it for 2 years.


the image is from their sales ad

they open the VCU up and clean all the blades from the old fluid (this can't be done through a tiny hole on each side), then they rebuild it and set it up with different amounts of fluid for different transference rate to the back wheels as you wish more or less traction according to you using the Freelander more or less off-road.

I just wish they hade done it like the VCU in the VW Syncro, it would be so much easier.
 
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Hmmmm does look like a more effective way to do it, if not more work. You guys who have had recons from the likes of bell etc. Does your vcu look like its been cut open? Any signs of new welding etc....any new fill or drain holes visiable......I do remember reading somewhere a guy that had a recon unit, Took a few pics of it and posted online. And all that was different was some extra drain and fill holes fitted.
 
There's nothing to say that the VCU can't be done at home with hand tools. I can't see why a grease nipple can't be substituted for a plug once filled. An air line can be used to blow most of the old fluid out Pryor to filling with the same quantity as that removed.
I did a synchro vcu years ago. It has screw in plugs.
 
Cutting open allows you betterer access to clean but there must be chemicals like brake cleaner of gunk which could be tipped into the vcu to help shift the contents via a small hole, with or without pressure. If the vcu is far gone then a cut open may be the only way.
 
Hippo said:
Cutting open allows you betterer access to clean but there must be chemicals like brake cleaner of gunk which could be tipped into the vcu to help shift the contents via a small hole, with or without pressure. If the vcu is far gone then a cut open may be the only way.
Click to expand...

I good flush out with a non residue cleaner would be good enough. If the casing is parted on a lathe, there will be a slight change in dimensions which can't be good.
 
Just curious but does normal Silicone fluid viscosity increase with temperature ?, in the Freelander the VCU fluid runs at more or less constant viscosity until about 95 deg C, above that temp the viscosity increases & by 105 deg C its at its maximum viscosity. Thats what makes it transmit the maximum drive to the back wheels within 1/4 turn relative front to rear of VCU, not sure off the shelf Silicon fluid has the same characteristic.
 
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