DIY VCU service

Unfortunately too busy at work at the minute to do much about it but think I will go ahead with what was sent.
Still planning to put enough fluid in at the start to cover the first half of the disks, then weld it closed slowly keeping it cool as I go, then squirt the remaining fluid in.

BTW I got the VCU end bolts from here. Not the exact right length but close enough and a whole lot better than spending £20 on a kit.
M10 X 1 Metric Extra Fine High Tensile Yellow Zinc Hex Head Bolts 20-100mm | eBay

Alibro said:

Right so I'm a little miffed ant the moment. I ordered this
Silicone Oil 100,000 100000 Cst 400ml Viscous Coupling Silikonol Freelander | eBay
Sent a message with it asking for 60,000cst (as suggested in the listing) and yesterday it came in the post. Yip you guessed it has 100,000 on the tub.
Now trying to decide If I should just go for it with 100,000 or send it back. To be honest I wasn't 100% convinced I should be using 60,000 anyway so unsure what to do now.
BTW it came in a generic plastic jar with 100,000 written on it in felt tip so I suspect the seller is repackaging the stuff and could supply any amount (so long as it isn't less than 400ml as he refused to send me 200ml). It just leaves me a little uneasy as to what is actually in the jar without a proper label.

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Do you have a link to the supplier? Maybe a picture of what you received too.

Nodge68 said:

Do you have a link to the supplier? Maybe a picture of what you received too.

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Mmmm Methinks a senior moment!
You included the link I put in my previous post when you quoted me.
The guy gets good feedback from all his buyers so it should be OK.

This is what came

Interesting properties in that stuff......

seems to work differently to VCU Dilitant fluid - Do yu know the particle size?

PDMS is also used in breast augmentation, so if you dont use all of it.......

Also, dont get it wet - because the hydrolysis reaction releases toxic hydrogen chloride gas.

Dimethicone is the active silicone fluid in automotive viscous limited slip differentials and couplings. This can be , but with mixed performance results due to variances in effectiveness caused by refill weights or non-standard pressurization.

Ok so latest update with pics

Gunge not oozing out.


All that came out after two days


The solution


Top off


I wanted to check what way the disks were inserted so pulled a few out checking cleaning and marking them as I went.



Once happy I turned it upside down and let gravity do the work.



I used petrol to clean them.


After cleaning the disks up I put them back in and used a large syringe to squirt the new fluid down the slots in the disks. By carefully lining them up and turning them frequently I was able to get around 100mls of fluid in. If doing it again I would just put the fluid in first then the disks as using the syringe was a pain. It is worth noting too that sucking the fluid up with the syringe was very hit and miss as it seemed to form lots of air bubbles so it was difficult to know how much fluid was in it. Probably best to weigh out around 100 mls and pour it in as suggested. Sorry no pics of this process. I only put in 100mls as I didn't want the fluid near the area I was welding. I planned to squirt the rest in later.

Top back on and welded back together. I used bits of cutting disk as spacers to try and keep the original depth and correct alignment, put in a few tack welds to hold everything then went for it. I had to cool it several times during the welding process.


After welding I ground back the welds with a flap wheel. I found out later this was a bad idea as it then leaked. My welding is pretty sh1te.


Before welding back together the holes were tapped with a 10mm extra fine tap.


I squirted another 50mls or so of fluid in before screwing in the grease nipples. Not sure if they will ever be used but they are a lot lighter than the bolts I bought so should have less effect on the balance of the finished propshaft.


After cutting the leaky bits again and rewelding I was less enthusiastic with the flap wheel this time.


All painted up and ready to refit. These are the new GKN bearings I bought. Not entirely convinced they are genuine GKN as they seem a bit rough to me but the bearing part is FAG so hopefully they'll be OK.



When the paint is dry and I've refitted it I'll report back how it performs the one wheel up test. I'll also try it in a muddy field to see if we really are four wheel drive although this isn't that important to me. I'll be happy if it is a little less inclined to spin the wheels in the wet.

Alibro, I think your the first to complete this task on lz. Well done.

Hippo said:

Alibro, I think your the first to complete this task on lz. Well done.

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LOL, congrats might be a bit premature. When it's been on working properly for a year without seizing and bolloxing up the IRD and rear diff then I'll accept a pat on the back.

Well done. Quite an achievement. Hope it works well.

Yep well done indeed......Many happy a mile motoring [emoji6] [emoji106]

Had my spare vcu draining now for about 3 weeks, 2 holes, 1 either side of the vcu. I've tried pumping white sprit through, got most of it out, like really thick toffee. It's still jammed solid. Think I'm gonna have to bite the bullet and cut it open so gonna bring it to work tomorrow night and do just that

Shanemag85 said:

Had my spare vcu draining now for about 3 weeks, 2 holes, 1 either side of the vcu. I've tried pumping white sprit through, got most of it out, like really thick toffee. It's still jammed solid. Think I'm gonna have to bite the bullet and cut it open so gonna bring it to work tomorrow night and do just that

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Go for it bud! What's the worst can happen????
One thing I found is that if the VCU is sitting upright it is harder to rotate as the plates are leaning on each other. Try turning it while sitting in the correct position for a while before you resort to cutting.
If you do cut it don't try to cut too near the end. I tried cut right at the weld and found some of the teeth on the outer wall needed cleaned up afterwards to get the plates out so prob best to cut just to the inside of the weld. Also I put a slight cut at right angles to the main cut so I had a mark to line it up when putting it back together.

Good luck.

Alibro said:

Go for it bud! What's the worst can happen???? [emoji14] One thing I found is that if the VCU is sitting upright it is harder to rotate as the plates are leaning on each other. Try turning it while sitting in the correct position for a while before you resort to cutting.
If you do cut it don't try to cut too near the end. I tried cut right at the weld and found some of the teeth on the outer wall needed cleaned so prob best to cut just to the inside of the weld. Also I put a slight cut at right angles so I had a mark to line it up when putting it back together.

Good luck.

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Just out of interest, how did you cut yours, I've not got access to a lathe or know anyone who has, I'm thinking of really taking my time with a thin cutting disc on an air grinder.

Shanemag85 said:

Just out of interest, how did you cut yours, I've not got access to a lathe or know anyone who has, I'm thinking of really taking my time with a thin cutting disc on an air grinder.

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Third photo shows how the VCU was supported. I held the grinder gently against it and turned the VCU until it cut through. If you could hold both more solidly it would do a neater job but unless your welding is a lot better than mine (wouldn't be hard) it won't make much difference in the end.

Quick update. I bolted the propshaft back on and tested it. The good news is I was able to turn one wheel up relatively easily and it is working in 4wd. I took it onto wet grass and with the door open watched the back wheel spinning. The missus thought it felt better when driving too which helps with the brownie points.
[emoji2]

Excellent thread, well done.

sounding good

Alibro said:

Quick update. I bolted the propshaft back on and tested it. The good news is I was able to turn one wheel up relatively easily and it is working in 4wd. I took it onto wet grass and with the door open watched the back wheel spinning. The missus thought it felt better when driving too which helps with the brownie points.
[emoji2]

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Nice one! How much fluid did you end up putting in?

guineafowl21 said:

Nice one! How much fluid did you end up putting in?

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Good question. I think I put in around 150mls but as the syringe filled with lots of air bubbles as I sucked the fluid into it I'm not really sure. To try and compensate for the air I drew around 60mls each time and pumped it in three times. Unfortunately I didn't have the brains to weigh the jar of fluid before starting so 150 is a best guess. It was enough to ensure the plates were all covered with the fluid well mixed in while the VCU was on it's end.

To be honest I will be a bit paranoid about it for a while but as it only takes a couple of minutes to jack up a wheel and check if it still turns I will probably be doing that fairly frequently for a while If I were doing it again I would defo go for the thinner fluid, I think 60,000 would be fine for a car used 99% of the time on the road.

One other thing I was concerned about was vibration If I had made it out of balance. I got it up to 70mph without an issue so that doesn't seem to be a problem.

i have 3 vcu sat on my garage floor right now all bollocked
i def think i may have to have a go at this as i love grindinding/cutting things lol and even more love to weld

how much did the fluid cost and where did you get it from please

griff

VCU's have a value regardless of condition. There are loads for sale on ebay for around £50 listed as spares/repairs.

Silicone Oil 100,000 100000 Cst 400ml Viscous Coupling Silikonol Freelander | eBay