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Thread: failed VCU wanted

  1. #1
    Join Date
    Aug 2018
    Location
    Brisbane
    Posts
    35

    failed VCU wanted

    Hi gents

    I'm looking for a failed VCU. Mainly because I want to x-ray it and try and fix it. Mine is close to giving up but not yet there so if anyone has a failed/seized one please let me know.
    I don't think it's that hard to fix them and once x-rayed I should be able to see how it's put together and hopefully test some theories

    I'm in Brisbne

  2. #2
    Join Date
    Jan 2016
    Location
    Netherlands
    Posts
    257
    Hi,

    I have one but shipping from europe... :P There is more information on these units already on the forum, I posted a bunch about it in the past few years I think. The most common failure seems to be the fluid aging and locking up the VCU permanently. I believe I also posted a youtube video of a russian guy refurbing one. It's not a really difficult job, you just need to drill two holes and flush the unit, afterwards replace the fluid (which can be bought over the internet) and that's it!

    If you can x-ray one though that would be awesome to see!

    -P

  3. #3
    Join Date
    Jan 1970
    Location
    Avoca Beach
    Posts
    11,323
    Ashcroft used to reco them , but AFAIR stopped partly because they used to fly apart when they sawed them open.

    The VW synchro ones are much larger and can be drained and refilled. Many years ago there was a how to on the net , which also showed the innards.
    They are really simple inside so I don't really think you have to Xray one. They are just a number of plates like motorcycle clutch plates , with holes in them. The thiroscopic? fluid thickens as it heats and locks up the plates.
    Regards Philip A

  4. #4
    Join Date
    Jan 1970
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    Avoca Beach
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    YouTube

    Regards Philip A

  5. #5
    Join Date
    Jan 2016
    Location
    Netherlands
    Posts
    257
    I have no idea what is beeing said here (russian) but the video speaks for itself:

    YouTube

  6. #6
    Join Date
    Aug 2018
    Location
    Brisbane
    Posts
    35
    i just want to xray one to see exactly where to drill, the fluid is readily available so to me it seems like a straight forward fix, my guess is you will need to weight the unit before drilling and after it's flushed so you know how much fluid goes back in and at the end give it a balance

    If Aschroft are opening them up then that would be stupid because they are sealed for a reason and the plates inside don't wear out unless somehow you manage to put enough torque one seized but that would break an axle beforehand or a diff.

    Mine is starting to lock from time to time and I can feel it on the highway, doing the rotate a wheel while jacked up works most of the time but not always so my guess at 320.000km it's on its way out

  7. #7
    Join Date
    Jan 1970
    Location
    Avoca Beach
    Posts
    11,323
    If you were selling reconditioned units you would have to replace the seal. IMHO that is why they would be opened.
    At 320Kk what do you reckon the seal would be like?
    Regards Philip A

  8. #8
    Join Date
    Aug 2018
    Location
    Brisbane
    Posts
    35
    it should be fine as Dextron III is amazingly good at keeping rubber fresh. If the oil is contaminated by a failed seal then yes the unit would be useless and I think it can be salvaged, it would just require treating it like a cast iron piece when welding it back together which would then require machining and re-balancing. Welding it can be robotised if you would do a lot in a batch but for personal use I would probably not bother and fine one that is not leaking. This can easily be tested.

    The one in my car should be ok, the oil is bright pink and it's been replaced at the correct intervals and doesn't look like it's contaminated. If I would work on someone elses VCU then I would pressure test it but I have never seen rubber perish in gearbox oil. Rebuilt a load of C4 trannies and some held up to upwards of 700HP and anything rubber in them never dies, some were not opened from the 60's with perfect front pump seals, actually using newer seals makes them leak.... go figure

  9. #9
    Join Date
    Jan 2012
    Location
    Bendigo
    Posts
    1,646
    I've got one you can have David.
    It was out of an LSE, though the same thing and was locked solid.

    Postage from Bendigo Vic might be an issue...

    Regards, Benji.

  10. #10
    Join Date
    Aug 2018
    Location
    Brisbane
    Posts
    35
    they aren't big at all, i'm interested

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