Can't bleed the slave clutch

Discussion in 'General Diesel Discussion' started by lgjonec, Jun 25, 2012.

  1. lgjonec

    lgjonec New Member

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    Car:
    2005 Jetta MK4
    Had to replace the slave clutch on a 2005 MK4 Jetta because I accidentally tore the boot. I can't get the air out of the clutch. I am bleeding with a hose attached to the nipple and I am opening it when the clutch is fully depressed and closing it before the pedal is released.

    There are microfine bubbles in the stream that won't bleed out. I've been through three pints of brake fluid. It seems like there is an air leak somewhere in the system (but I had no problems with the system before). I think I might be hearing a hissing sound near the fluid reservoir when the pedal is depressed.


    Any ideas?
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  2. YMZ

    YMZ Super Moderator

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    Car:
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    Latitude 44.407959, longitude -76.018369.
    welcometomyturbodies Welcome to the website!

    These cars are designed for the hydraulic systems to be bled using a pressurized system... Motive makes power bleeders with the correct size cap that many people use, and some have made their own... Attention must also be paid to make sure that the fluid level in the brake fluid reservoir never falls below the feed hose to the clutch master cylinder... (it's positioned higher than the brake feed...)

    HTH...

    Yuri
  3. chittychittybangbang

    chittychittybangbang Administrator

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    If the brakes were just bled, you could try a recirculating purge since you've already flushed 3 pints through the system. See FAQ for tips. Not for use with a single drop of old fluid! But can help with pesky bleeding. You could just have a bubble stuck in there which needs some vigorous working out. In rare cases you just have to bench bleed (pre bleed out of car).

    Or the new slave is defective :D
  4. Ol'Rattler

    Ol'Rattler Active Member

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    Car:
    06 TDI Jetta
    You need to keep the M/C full. Cracking the bleeder 3 times will introduce air back into the clutch because the clutch tap is so high on the M/C.

    You can take a hose from the bleeder and put the other end in the M/C. As long as you keep the M/C full, all the air will get worked out when you bleed.

    When I changed my slave, I went through less than a liter of fluid but I made sure the M/C level never got low.
  5. NIW

    NIW New Member

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    Car:
    2001 Jetta TDI & 2006 TDI Jetta
    Mods:
    On 2001, 5 speed swap, interior up date custom pro
    I am having a similar issue, however, can anyone tell me if, after diligent bleeding of the slave ( 10 + times over the last two months, not correcting the issue after every attempt however) , and the car is back to shifting like butter it will without warning, go back to not fully disengaging - minutes, days or weeks later. Here's the part that is blowing my mind! ; it will go back to fully disengaging on its own, it just did it on the drive back home tonight. Air in the system is air in the system is it not? how could the problem rectify itself like it is? Help - what am I looking at here. Thanks for taking the time.
  6. chittychittybangbang

    chittychittybangbang Administrator

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    Yes, once you get a bubble in clutch line, it usually stays there for a while. Maybe related to clutch slave cyl leak ? Very unusual for it to fix itself.
  7. NIW

    NIW New Member

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    Diagnostically I have to consider the following: 1) Since I am not loosing any system fluid over the past 2 months (2000 km) of driving, I have repeatedly flushed the clutch system like it had food poisoning and the fact that the clutch pressure restores itself , air in the line has to be considered secondary to the issue. 2) There must be a mechanical/hydraulic malfunction that reappears ; like spinning Pat Sajaks wheel of misfortune " Loose a Clutch". Therefore I ask, is there any way an O ring or some sort of pressure seal could be moving around/ failing and then correcting itself in its journey in either the Clutch master cylinder or in the Slave cylinder? and if so which one would have the greatest chance of producing this type of migratory failure? Or, is there any scenario where I have made a gross mistake when installing the 5 speed swap and my clutch,flywheel and or transmission are about to fly apart?. Any thoughts or recommendations would be appreciated from the TDI community.
  8. chittychittybangbang

    chittychittybangbang Administrator

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    I cannot think of any failure like this that would fix itself. My best guess is that it's a mechanical problem like you said, a seal which is fixing itself as it moves back and forth. It's not in the clutch-flywheel-lever because I cant see anything there which would affect clutch pedal travel adn then fix itself. If you figure this one out, please post a follow up!
  9. NIW

    NIW New Member

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    I have just completed a closed loop bleed. With trusty wife by my side and watching the clear return tube NO air bubbles! I pumped the crap out of it. Now going for a drive. If not successful ( not being negative) which unit should I replace first? Any guesses.
  10. NIW

    NIW New Member

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    On 2001, 5 speed swap, interior up date custom pro
    Can't get out of the driveway. Think I will start with the Clutch Master Cylinder.
  11. Ol'Rattler

    Ol'Rattler Active Member

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    Not sure how to tell which is bad, but the slave would be easier. You could at least remove the slave and check for leaks inside the rubber boot before you go to the hassle of removing the master.
  12. NIW

    NIW New Member

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    On 2001, 5 speed swap, interior up date custom pro
    I orderer both the slave and master, Beck Arnley. Looks like good quality metal units. I installed the slave and bleed the system. Put under the hood back together and went for a drive. Nice. This morning had a little trouble with getting into reverse. I am going to drive it for a couple of days and see if the issue comes up again, if so, the master goes in and that better be that. Thanks again.
  13. NIW

    NIW New Member

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    Car:
    2001 Jetta TDI & 2006 TDI Jetta
    Mods:
    On 2001, 5 speed swap, interior up date custom pro
    Replaced the Slave a couple weeks back, had a bit of an issue but then all was well. Earlier this week the problem came back so I thought OK it has been the master all along. I just replaced the master, headed out for a drive - alls well. Then CRAP, can't shift same non-disengaging. There is no leaking at incoming or out going ends of the master, no leaks on the pressure line, no leaks at the slave. Beck Arnley slave 0729255, Beck Arnley master 0729321. Could someone put some thought to what could be going on here and post back to me. In the mean time I am going to bleed the system one more time. The fluid is fresh DOT 4 racing blue. Thanks for any help you can offer. Ian

    Just Bleed it through again - no change.

    I have removed the slave made sure it was sitting square, reaching in with a finger the contact area ( fork ) had about 3/16 " of wiggle. Tested the amount of movement on the slave, only got 3/4" to maybe 1 inch of push from the rod could my new master be faulty or is this what is to be expected for movement on the slave?
    Last edited by a moderator: Jul 19, 2012

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