VCU Torque test results

Alibro · Feb 23, 2016

Nodge68 said:
The VW Synchro VCU has 2 screw in plugs at 180° spacing which I assumed was allow the fluid to be changed. However on more research I found that the end cap can be unscrewed for maintenance. The 2 screw caps are in fact, a cast in lump and 180° round a brake type bleed nipple for filling and venting.
I'm going to make my own plugs and fill using a grease nipple. Hopefully pumping new fluid in will force the old fluid out. I'm thinking of orientating the fill at the top, hopefully allowing the old fluid out the bottom.

Makes more sense as the only way to refurb VCU's properly is to take the discs out and clean them thoroughly. Any other way might work up to a point but will always be compromised by a mixture of old fluid and residual cleaning solvents.
I used grease nipples on my first one but the nipples I bought were very shallow so there isn't much thread holding them in, only 5mm or so. The ends are around 10mm thick so if you can get nipples with more thread then do. I used one bolt on the second one and cut the bolt to length, I only drilled one hole and it worked fine, I welded a second bolt head on for balance.
Not sure if it helped strength wise or not but I bought extra fine bolts and nipples and used an extra fine tap.

Nodge68 · Feb 23, 2016

Alibro said:
Makes more sense as the only way to refurb VCU's properly is to take the discs out and clean them thoroughly. Any other way might work up to a point but will always be compromised by a mixture of old fluid and residual cleaning solvents.
I used grease nipples on my first one but the nipples I bought were very shallow so there isn't much thread holding them in, only 5mm or so. The ends are around 10mm thick so if you can get nipples with more thread then do. I used one bolt on the second one and cut the bolt to length, I only drilled one hole and it worked fine, I welded a second bolt head on for balance.
Not sure if it helped strength wise or not but I bought extra fine bolts and nipples and used an extra fine tap.

I agree that there will be an amount of old fluid left in the VCU with my perspective method of fluid replacement. I've chosen a lower viscosity (30,000cts) than the factory (100,000cts) viscosity. This was deliberate as I knew a fair amount of old fluid is likely to remain in the unit. I'm kinda hoping that a mixture of old and new will do what I need.
Time will tell I guess.

GrumpyGel · Feb 23, 2016

Have you thought about what gap you'll leave?

Alibro · Feb 23, 2016

GrumpyGel said:
Have you thought about what gap you'll leave?

I'm not convinced it matters that much with the methods we're using. The exact method and materials are obviously closely monitored and measured during manufacture so that the car has predictable characteristics when new, but all we want (most of us) is the damn thing working well enough to be able to call it 4WD without it buggering up the drive train.

Nodge68 · Feb 24, 2016

GrumpyGel said:
Have you thought about what gap you'll leave?

I don't believe the air space makes much difference. As long as it gives enough room for expansion of the fluid. A space of 10 to 20 ml should be enough.

Nodge68 · Feb 24, 2016

Alibro said:
I'm not convinced it matters that much with the methods we're using. The exact method and materials are obviously closely monitored and measured during manufacture so that the car has predictable characteristics when new, but all we want (most of us) is the damn thing working well enough to be able to call it 4WD without it buggering up the drive train.

Basically my thoughts too.

GrumpyGel · Feb 24, 2016

Well I suppose if you are going for 30,000cts, you may as well do away with hump mode.

Possibly give you very weak drive and and high rates of wear in the VCU if you drive on a lot of slippery stuff.

Would be interesting to see it on 1 of those ramps that test 4WD - the type that has rollers where the front wheels are once on the ramp.

ponythegringo · Feb 24, 2016

Hi all , just did a vcu test today using a 1.2m bar and a 7.5 kilo weight as i felt the car a tiny bit stiff in full reverse lock . It took about 30 seconds to do a 45 degree turn .
td4 69k seems to be original vcu.

Martin R · Feb 24, 2016

Im going to try this on my 48K 56 plate, i will post the results. Should the turn be from the centre nut on the hub?

GrumpyGel · Feb 24, 2016

Martin R said:
Im going to try this on my 48K 56 plate, i will post the results. Should the turn be from the centre nut on the hub?

Yes, a 32mm socket fits it.

ponythegringo · Feb 24, 2016

Ok, had a look at socket set that santa brought and it does indeed have a 32mm socket . I guess i had better do it properly tomorrow and post again.

Should i do 5kg instead of 7.5kg ?

Alibro · Feb 24, 2016

I've always done the test using a 5kg weight, partly because it is easy to find a 5 litre container to use as a weight, but mostly cause all the videos I watched before doing it the first time used 5kg. If we all stick to the same weight we will be able to compare times easily.

ponythegringo · Feb 24, 2016

Oke will redo with 5kg

Martin R · Feb 24, 2016

I will try it at 1.2m and 5 kg as soon as I get a chance and post the result.

Martin R · Feb 25, 2016

Right just done the one wheel test on mine. 1.2M @ 5kg @ 45 degrees. I did the test 3 times on a cold car the average was near enough 40 seconds. Just to recap a 56 reg manual TD4 with 48K on the clock about 5 degrees C ambient temp as i presume this may make a slight difference? I intend to do this every 3 months or so as it takes very little time to do. I will see if there is a noticeable deterioration. Also just for reference there is slight resistance when reversing on full L/H lock. I guess this is normal.

Alibro · Feb 25, 2016

RESISTANCE IS USLESS! I mean normal,

You know to worry when you hear the wheels scrabbling on dry ground.

Nodge68 · Feb 25, 2016

Alibro said:
RESISTANCE IS USLESS! I mean normal,
You know to worry when you hear the wheels scrabbling on dry ground.

Ah a classic quote from HHGTTG!!. I saw the live stage show in 2013. It was very good I thought. The wife wasn't impressed tbh. She wondered why people were waring dressing gowns.

Alibro · Feb 25, 2016

LOL, Should have known better than taking the wife. Women don't get it.

4x4Dog · Feb 26, 2016

Gonna try to get around to checking mine this weekend. Freelander 06 with 120k plus change on the clock. VCU prolly original. She's not done much off roading at all, and she had a new set of BF Goodridge's at 70k that are wearing evenly. No feeling of tightness or binding.

Still, given the mileage, I'm prolly gonna change the VCU whatever the result ASAP.

4x4Dog · Feb 26, 2016

Ahhh, the suspense was killing me so I went out to give it a whirl.

So, 32mm socket on a breaker bar, ally pipe making it up to 1.2 meters. Hung a 5L bottle of coolant off the pipe.

I did this in the old "measure by eye, mark with chalk, chop with axe, hammer to fit" style, so I eyeballed the 45-90 deg marks. All at ambient air temp today (say 10c for ****es and giggles).

Result.

I did several runs, and all fell in the 45 to 50 seconds mark. So, it's not seized which is good, but it's clearly not a virgin either. So, bottom line, it's gonna get replaced.

VCU Torque test results

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