# How to bleed your 02M clutch slave cylinder, the effective way.



## golfcabriolet90 (Nov 21, 2004)

Well here it is, this guide is a follow op to my other thread regarding this topic: 
http://forums.vwvortex.com/zerothread?id=4321537

Basically there is a flaw in the design of the clutch slave cylinder layout in the 02M gearbox that makes it difficult to bleed it.
The bleeder valve is located outside of the bell-housing and is attached to the slave cyl which is inside the bell housing. Because of this, the tubing in the slave cyl is never flushed by a normal bleed.
The parts in the red square are therefore not bled normally.








This fluid will have drawn air and moisture to it over several years (due to never being flushed) and can cause a spongy feel in your clutch and the point at which the clutch dis- and engages will sink towards the floor. All this happens at times when your engine bay is warm and the fluid then expands due to the water+air mixture absorbed in it.
Here's what you can do to flush this old fluid out. Please note I accept no responsibility for the use of this guide or its outcomes.
Tools: Syringe with tube (see below).
Materials: DOT4+ original VW/Audi brake fluid, get 1L to be on the safe side. 2x new O-rings for the bleeder valve, available from VW part no. 02F 141 143 A (for euro v6 4motion).

You need a syringe to which you have attached a small tube. I'm in med. school so have access to these but you can probably buy them at a pharmacy. 20ml. is a handy size.
The tube you'll attach to it must be very thin as the internal diameter of the slave is narrow. The tube I used was a mere 2mm in diameter measured externally. You'll probably have trouble finding tubes like this in a hardware store, and that's why I used 30cm of electrical wire where I'd carefully pulled all of the copper wiring out of it.
Next you need a small bit of tube with an internal diameter of about 3mm, this is used to fit over the syringe, you'll then glue in the thinner tube into the wider tube that fits on the syringe with a 2 component epoxy glue. The final product will be something like this:

















With the syringe ready and the glue hardened you can move on to the job.
1. Clean the areas around the bleeder valve.
2. Disconnect the bleeder valve in both ends, start with the right and quickly tape up the pipe from the 'clutch pedal end' and close the end of it to make sure it doesn't leak all over parts or gets dirt inside it. To disconnect tubing, just pull up the metal clips and you can pull the tubes to the side.
3. Take the bleeder valve to the side and put it in a clean plastic bag to avoid dirt getting into this as well.








4. Place a clean rag under the opening of the slave cylinder, one with enough fabric to suck up some brake fluid.
5. Fill up your syringe with fresh brake fluid but not using the thin tube yet.
Hold the syringe upright, tap the side of it and purge the air out of the syringe.
6. Now attach the thin tube assembly. Begin to push brake fluid out of the thin tube till you see it run out with no air bubbles.
7. You are now ready to insert the tube into the slave cylinder, but this must be done while you apply a little pressure to the plunger of the syringe, in other words the end of the thin tube needs to be dripping fresh brake fluid as you insert it into the slave cyl. This way you avoid the possibility of a small air bubble entering the system from the end of the thin tube.
8. Push the tube in as far as you can, I was only able to get it in about 7cm (even tried with a steel wire to guide it in, but no go) even though the complete system should be much longer. However flushing these 7cm cured my problems.
9. Now gently push the plunger of the syringe so you can see brake fluid drip out of the slave opening, flush about 5-10ml. After this, gently pull the tube out of the slave cylinder in small increments of about 3mm every 2 seconds, you must at the same time push fluid out as you do this. Do this until you have pulled the tube all the way out.
You can repeat this procedure step 5-9 if you feel like it, I did it 2 or 3 times just to be on the safe side.
10. With the flushing all done you simply re-attach everything in the reverse order, remember to install the 2 new O-rings by the bleeder valve!
11. Finally you need to bleed the system the conventional way with 2 bar pressure power bleeding. There will be a lot of air in the bleeder valve housing now that needs to be taken care of. Use your Bentley manual for this or the diy on the vortex describing this procedure.


_Modified by golfcabriolet90 at 4:42 PM 5-5-2009_


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## Xacto (Feb 25, 2002)

Saved for future reference, thanks!


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## JettaRed (Aug 14, 2000)

*Re: How to bleed your 02M clutch slave cylinder, the effective way. (golfcabriolet90)*

This should be an FAQ in the tranny forum!


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## GarrettsDad20v (Jan 5, 2010)

*Re: How to bleed your 02M clutch slave cylinder, the effective way. (JettaRed)*

nice write up


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## waabaah (Jun 24, 2006)

*Re: How to bleed your 02M clutch slave cylinder, the effective way. (GarrettsDad20v)*

im having this problem right now..been bleeding for 5 hours after a simple clutch job!








i swear i flushed out the whole braking system with just the slave cylinder bleeder. lmao


_Modified by waabaah at 9:44 PM 3-28-2010_


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## volkswagendude01 (May 1, 2006)

do you still have this tool you made and will you sell it, im about to put a brick on the gas petal and watch it go off a cliff.. and i got kicked out of the pharmacy for asking for one lol


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## Lucky736 (May 11, 2002)

Does this same theory about poor design apply to the B5 S4 by chance.


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## golfcabriolet90 (Nov 21, 2004)

Sorry for the late reply.

Yeah I still have my tool, but I think I'd like to hold on to it should I need to do a flush again.

Why can't you buy a syringe at a pharmacy?
I mean you're not asking for a needle or anything (I hope )

If all else fails, I know you can buy syringes by purchasing a motorcycle front suspension fork refill kit. They always include a big syringe, should work in this application too.

With regards to the Audi S4 design, I'm not sure but chances are they are very similar. I know the newer Golf 5 uses the same design/flaw.


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## volkswagendude01 (May 1, 2006)

it actually just started working.. i just kept driving the car cause i had no time to deal with it, and when it would stop working which was about every time i got into the car after parking it, i would just crack the bleeder and bleed it till it worked again, top off fluid, and out of nowhere it worked.. i guess i just got all the air out from being paitent and fussing with it


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## golfcabriolet90 (Nov 21, 2004)

You may be right.

Guess you eventually purged that air you had.


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## Ephry73 (Feb 18, 2002)

Stupid question about slave clutch cylinder. Do you guys reuse your bolts for the cylinder or get new ones? Red or blue loctite? 

Thanks,


E


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## my02VR6 (Jan 6, 2005)

Ephry73 said:


> Stupid question about slave clutch cylinder. Do you guys reuse your bolts for the cylinder or get new ones? Red or blue loctite?
> 
> Thanks,
> 
> ...


NEVER use red unless you don't want to take the bolt back off


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## Maynard89 (Nov 1, 2009)

the two metal clips that hold the bleeder tube in place.. Anybody have any idea how i can get a hold of one of the clips??


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## rawk (Jul 29, 2000)

Maynard89 said:


> the two metal clips that hold the bleeder tube in place.. Anybody have any idea how i can get a hold of one of the clips??


 I need them as well and not having much luck finding the part number... anyone? :thumbup:


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## 24vGTiVR6 (Sep 14, 2010)

rawk said:


> I need them as well and not having much luck finding the part number... anyone? :thumbup:


 I needed one of them - went to the dealer and they said that the spring clips aren't available on their own, only part of the bleeder valve assembly.


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## rawk (Jul 29, 2000)

24vGTiVR6 said:


> I needed one of them - went to the dealer and they said that the spring clips aren't available on their own, only part of the bleeder valve assembly.


 Yah I did the same, I actually spent 5 minutes messing with a paper clip and it will work perfectly. I had one OEM clip to use as a guide and just bent the paper clip to a similar shape, it holds the line in perfectly and saved me $50 on the bleeder valve :laugh:


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## VR6itch (Mar 19, 2004)

Where is the slave cylinder located? Is it in the tranny?
I just ordered a part and want to make sure I got the right one.
It's 1J0 721 261J.
Thanks, I've searched and couldn't find a clear picture.


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## 24vGTiVR6 (Sep 14, 2010)

VR6itch said:


> Where is the slave cylinder located? Is it in the tranny?
> I just ordered a part and want to make sure I got the right one.
> It's 1J0 721 261J.
> Thanks, I've searched and couldn't find a clear picture.


In the 02M the slave cylinder / throwout bearing is located inside the bell housing of the transmission. You'll have to drop the trans to get to it unfortunately.

I'm not 100% sure about part #'s tho.


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## VR6itch (Mar 19, 2004)

sweet, thanks!:thumbup:


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## mk3_vdub (Oct 18, 2006)

what exactly did you use for that clear section of the tube? was it medical stuff as well? my mom is a nurse so i need to know exactly what to tell her to grab for me

what gauge wire did you use?

subscribing bc i will need this this weekend


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## Brett VR6 (Jan 29, 2008)

*Get the ECS Bleeder block*

This was some of the best money I spent on my car. Only took me like 30 minutes to install too! The bleeder is also a little easier to get to

-Brett-:beer:


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## platinumdub-18t (Jul 1, 2008)

a far easier option is to just dunk the slave cylinder in an open jug of brake fluid, and pump the cylinder many, many times until all of the air comes out. then push a clear hose onto the end of the cylinder an finish the bleed into an open pop bottle with the hose end submerged...










can do this without any special tool to make in about 2-3 minutes guys... don't over-complicate things.

after you put the slave cylinder back into the tranny, just put a cap/electrical tape over the end of it... cause when you bolt the tranny in place, you will compress the cylinder and it will shoot brake fluid into your eyes.... ask me how i know (I wear safety glasses though, hehe).

once the tranny is bolted up, remove the cap/tape and connect the bleeder block, then bleed clutch line as normally would a brake caliper, and what you'll find is that the tiiiiiny tiny little bit of air that got into the end of the cylinder after you were finished pop-can-mcgiver-bleeding it will rise upwards and come out of the bleeder block screw "over time".


so in summary...

1. dunk and pump the slave cylinder in an open jug of (clean) brake fluid.
2. stick hose on end of cylinder and submerge other end in (same) jug of (clean) brake fluid, pump again until all air bubbles make their way to the holy land.
3. install with cap over end of cylinder to prevent spraying into your eyes or on your new paint job.
4. bleed as you would a brake caliper, then after about 5-10 minutes, bleed 1 more time to get the last inkling of air out.
5. enjoy the **** out of your super-firm o2m clutch pedal feel and send me thank-you notes to my inbox.

have done this literally dozens of times now - super fast, no special tools needed, and consistently works.


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## 24vGTiVR6 (Sep 14, 2010)

yeah - I bench bleed it as well _now_ (much easier definitely), but what if the trans is in the car?


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## RodgertheRabit II (Sep 13, 2012)

24vGTiVR6 said:


> yeah - I bench bleed it as well _now_ (much easier definitely), but what if the trans is in the car?


would like to know the same


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## 24vGTiVR6 (Sep 14, 2010)

sorry I meant that as - if the trans is in the car, use this method. It worked for me.


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## D2O (May 12, 2012)

I just got a new slave cylinder and was bleeding it by pumping it with a hose in the jug of fluid, and found that every once in a while the slave will leak while the piston is depressed. Is the slave fubar'd? Anyone else run into this? I finally have a free weekend to put the car together and I have a feeling I am screwed....


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## platinumdub-18t (Jul 1, 2008)

sounds like it could be damaged. if they get over-extended, it can damage the seal. i once accidentally installed a TDI 02m clutch disk (which requires a much longer throw-out bearing than these), and it over-extended while bleeding the clutch line and leaked. it would hold pressure until a point, then start leaking. i wasn't aware i was sold a TDI 02m clutch disk, lol - the fingers on it are very different once its compressed, but look almost identical when not. :facepalm:

you will not be very successful if you put a dry bearing into place then attempt to bleed it from scratch.. it is 100% worth while to pull the tranny and bench bleed every time to ensure that its fully hydro-locked.

FYI - an 02m tranny can come out extreeeeeeeemely fast if you just pull both axle cups and lower the engine on about a 15* incline. I've pulled VR6/1.8t 02m's in less than 30 min with the support of it hanging from a cherry-picker crane. do it right, do it once guys.

If anyone has any questions on this, feel free to PM me. I'd be happy to walk you through the details as required.


Random additional point --- R32 pressure plates do not mix well with the FWD 02m flywheels. causes many issues for people and those little spacer plates are generally required to offset these bearings so they don't leak. not sure on the audi TT stuff -- maybe someone can add to this.


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## cruzanstx (Oct 10, 2011)

Coming from TT 02M side just want to point out that I did mine today with a manual pump brake pressure bleeder. Had the same dead pedal issue prior to doing it. This looks pretty creative but if you can get a pressure bleeder it's super fast < 10minutes. The one thats used at this link is similiar to the one I used. http://forums.vwvortex.com/showthread.php?5098953

Sent from my HTC One using Tapatalk


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## hamyscj (May 7, 2015)

platinumdub-18t said:


> sounds like it could be damaged. if they get over-extended, it can damage the seal. i once accidentally installed a TDI 02m clutch disk (which requires a much longer throw-out bearing than these), and it over-extended while bleeding the clutch line and leaked. it would hold pressure until a point, then start leaking. i wasn't aware i was sold a TDI 02m clutch disk, lol - the fingers on it are very different once its compressed, but look almost identical when not. :facepalm:
> 
> you will not be very successful if you put a dry bearing into place then attempt to bleed it from scratch.. it is 100% worth while to pull the tranny and bench bleed every time to ensure that its fully hydro-locked.
> 
> ...


Getting ready to replace my trans and clutch. Thanks for the tip on the axle cups. I don't think I'll get it out in 30 minutes but hopefully this will save some time. :thumbup:


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## hamyscj (May 7, 2015)

Update: The trans swap went surprisingly smooth. Bleeding the clutch even smoother. Gravity bled for a bit, pumped the pedal a few times and it works like butter. 
Guess I got lucky. 

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