Clutch Slave Cylinder Install Tips and Bleeding 101 by JHM

[jaybquick@JHM]

Being that I sell alot of transmission related parts (shifters, linkage upgrades, clutches, flywheels, transmission rebuild kits, etc.) I have been getting more and more calls with tech questions regarding our good friend the slave cylinder.

So I figured I would summarize the common problems and the best bleeding procedure for the DIY guy. Obviously a pressure bleeder is the OEM recommended way, but I doubt many of you have those.


IMPORTANT TIP New as of 5-11-09
We have found that if you try to bleed the clutch with the car NOT completely level. Like if you just jack up the front. You will almost NEVER be able to bleed it completely or will make it take forever. This traps air bubbles in one of the upper corners. So make sure the rear of your car is level with the front of your car and if not level even a little higher than the front. The key is to not have the front higher than the rear. We have always bled ours when the cars were level and routinely do it in 5 minutes or so. Well recently I was lazy and tried to do one with just the front of the car up and I couldn't get it to bleed for me no matter what I did. I thought about it and it hit me why. So I jacked the back of the car up and BOOM, it bleed quickly. Hope this new tip helps some that are struggling.


NOTES:
The Slave Cylinder uses the same reservoir as the brakes, which requires a Dot 4 brake fluid. And of course we sell them here --> Clutch Slave and Master Cylinder


INSTALLING PROPERLY:
This is a commonly improperly installed item during a clutch job or any trans pull. First off I highly recommend not unhooking the hose from the slave unless you are replacing the slave cylinder. I recommend you just undo the 1 6mm allen(hex) bolt that holds it in place and leave the slave in the car still attached to the hose. This will save you the pain of bleeding. IMPORTANT: When you put the slave cylinder back in the trans (only after the trans is completely bolted back up to the motor) it should not slip in super easily especially if it has not been replaced and has no air in the system. You should also always start by putting a thin layer of grease on the outside of the boot where it goes into the trans so it does not catch and hang up when putting it in, this helps a lot. You have to make sure the pushrod goes into the clutch fork, this is very important or you can pop the piston and rod clean out of the slave cylinder and run the risk of it falling into the bellhousing and need to be removed by pulling the trans again. Then have to buy a new one, since you don't want to risk it leaking once you figure out how to reassemble it, if you even can. When it hits the fork you will feel steady resistance and takes time to get it to compress and push fluid back into the brake reservoir (be patient and keep pressure, it takes strength to do this). Once it is in, it will drop into a catch on the trans that will hold it in place, at this point just reinstall the 6mm allen (hex) bolt and tighten it down. If it goes in super easily you most likely missed hitting the clutch fork with the push rod. However, if you have a new slave cylinder that you installed or have air in the system for any other reason it will be pretty easy to install. So another way to confirm engagement is push on the clutch pedal with your hand, not foot. It should give you resistance if it is not full of air. It should also feel funny the first time if you have a SAC style clutch pressure plate (OEM or RS4 type) since the SAC mechanism is setting itself. If you push the clutch pedal and it feels like it bottoms out and gets very hard, DO NOT FORCE IT. You are feeling the piston bottom out in the bore since the pushrod is not engaged into the shift fork and if it you press it one more time, POP goes the piston and rod out of the slave cylinder. Hope this info helps you with your transmission and or clutch install.

BLEEDING

** NOTE: You usually have to crack the bleeder screw .5 to 1 full turn to get any fluid/air to come out. **

Similarly to Brakes, Clutch hydraulics (slave or master) need to be bled after being opened or when a component is replaced. Also, you always need to make sure the brake/clutch fluid reservoir is full and stays above the level of the hose that comes out the side of the reservoir, this hose is what feeds the Clutch Master Cylinder so if the level gets below this hose you will then start sucking air into the clutch hydraulics and have to start your bleeding procedure all over again.

NEW CYLINDERS OR FULLY DRAINED SYSTEMS. With all that air in there, it will just aerate the fluid and never bleed if you try the old pump it up and then hold it to the floor routine and then have someone crack the bleeder after. INSTEAD crack the bleeder FIRST, then push the pedal to the floor and hold it. Then while still holding the pedal to the floor close the bleeder. Then pull the pedal up, only once the bleeder is closed. Repeat this procedure several times until fluid comes out. Once fluid comes out then do it at least 2 more times to be careful. At that point you can switch to the old pump it up and hold it to the floor method. To do that, you just pump the clutch pedal several times, then hold it to the floor. While the pedal is on the floor crack the bleeder and then close. Repeat this 2 to 4 times just to be sure. At this point the pedal should feel great. Once you think you have it, give it a 30 minute break to make sure any incedental aeration settles down. Then come back and bleed it one more time, if you hear or see air do it again. If at any point you start with the pump it up first then crack it method you should give it a 30 minute break to let the aeration go away in the fluid. Once you aerate the fluid and just keep trying, you will be there forever and it will never bleed properly. PATIENCE AND PROPER PROCEDURE ALWAYS PREVAIL.

FINAL BLEEDING IF YOU ONLY HAVE A LITTLE BIT OF AIR IN THE SYSTEM
For this the old pump it up and hold it to the floor method usually works fine. To do that, you just pump the clutch pedal several times, then hold it to the floor. While the pedal is on the floor crack the bleeder and then close. Repeat this 2 or more times just to be sure. At this point the pedal should feel great. Once you think you have it, give it a 30 minute break to make sure any incidental aeration settles down. Then come back and bleed it one more time, if you hear or see air do it again. NOTE: Once you aerate the fluid and just keep trying, you will be there forever and it will never bleed properly. You must step away for at least 30 minutes to get the fluid to not be aerated.

GRAVITY BLEEDING
This is a great technique when you replace the slave cylinder to save you headache and time.
1. Get the new slave cylinder installed; bolted in completely and connected to the hose.
2. Make sure the brake fluid reservoir is full (clutch master and slave share this reservoir with the brakes)
3. Crack the bleeder screw at least 1 full turn (360 degrees) to 2 full turns (720 degrees0
4. Put a drop pad or rag below it on the ground.
5. Take a break and within 5 to 30 minutes you should see fluid dripping out.
6. Once the fluid starts dripping tighten down the bleeder.
7. It is now about 90% ot 95% bled and now you may only have to do the above bleeding procedures once or twice. This saves a lot of headache and aerated fluid.

I hope this info can be of use to you guys, this info is free as a courtesy for your continued help and support of my business.


NOTE:All JHM customers that buy their parts us get this kind of knowledge and tech help. So be careful who you buy from. Can you call on them for help when your car is apart and you are stuck??? Also, due to our higher email(preferred contact method) and call volume as of late we obviously have to help our paying customers first and sometimes can't get to other emails or calls for a day or so. I would love to help everyone but I can't so I do the fairest thing I can, help those who help me.



Thank you everyone for your continued support. Keep checking out our new store for new aftermarket and replacement parts. We are adding new products every week and are seeking out more suppliers and new accounts. If it is not on our store yet, we can most likely get it within a few days at a great price.

[lowered97a4]

hate bleeding and installing those things, reading this makes it easyeir next time i goto do this thanks

[PinoyS4]

nice write up

[laxman851]

Nice write up... i'll admit we threw the rod but it didnt fall into the bell housing, the slave boot caught it, lucky us.

[generationjdm]

Nice write up very helpful The worst thing you can do when bleeding is pump the clutch pedal like a brake pedal this causes a ton of little bubbles out of the one big bubble that was there and will have u bleeding for hours, Unless you do what Jay says "let the car sit for a while and come back"..

[HighDesertAudi]

This was the most PITA part of my turbo swap. It took me and a buddy a good hour trying to cram that thing back onto the clutch fork. Good writeup alot of people ruin their slave cylinders doing it the wrong way.

[jaybquick@JHM]

Thanks guys.

I know the pain of headaches like this. I lived them all. 16 years later of wrenching and modding cars I have lots of knowledge and luckily don't have those headaches much anymore. Plus I feel bad everytime I sell a slave cylinder knowing why they usually are messed up. Of course I like making a sale, but I lived similar pain with cars back in the day and it sucks. The internet wasn't available for help, just hours and hours and many broken parts later. HAHA. Ah the memories.

[jaybquick@JHM]

Got this question so I thought I would post it up here to update the thread.

I was reading your write up on bleeding the slave cylinder. I know it uses the brake reservoir , but am i right to assume that you can bleed the slave cylinder without bleeding the brakes?

The answer is Yes. They just happen to share the same fluid reservoir but are two totally separate systems otherwise.

[BurnAll4S4]

hmmmm...mine has 'popped' about 4 times now with taking the trans off and motor out and everything, and just not seating it right. its not really difficult to put it back together and have it not leak.

other then that, good write-up.

[jaybquick@JHM]

hmmmm...mine has 'popped' about 4 times now with taking the trans off and motor out and everything, and just not seating it right. its not really difficult to put it back together and have it not leak.

other then that, good write-up.

I hear ya on that. I have done it in the past with other cars, but for most people this part is a PITA to replace so sometimes it is just better to be safe than sorry and replace it. But you can definitely try it since late at night (when most enthusiasts wrench) if it falls apart, it is not like you can go buy one at walmart.

[jaybquick@JHM]

Had a lot of calls about this and realized I had more info to share:


FIRST OFF. NOTE: You usually have to crack the bleeder screw .5 to 1 full turn to get fluid/air to come out.


GRAVITY BLEEDING
This is a great technique when you replace the slave cylinder to save you headache and time.
1. Get the new slave cylinder installed; bolted in completely and connected to the hose.
2. Make sure the brake fluid reservoir is full (clutch master and slave share this reservoir with the brakes)
3. Crack the bleeder screw at least 1 full turn (360 degrees) to 2 full turns (720 degrees0
4. Put a drop pad or rag below it on the ground.
5. Take a break and within 5 to 30 minutes you should see fluid dripping out.
6. Once the fluid starts dripping tighten down the bleeder.
7. It is now about 90% ot 95% bled and now you may only have to do the above bleeding procedures once or twice. This saves a lot of headache and aerated fluid.



Thanks to DAFT an AZ moderator for me getting this on here. He called me today regarding the info in this post.

[Daft]

Jay thanks again for the tip on the gravity bleed procedure.

BTW, I got the boot out with the pushrod! I only had to disconnect the axle and remove the driver side trans support.

BTW, another useful tip that I came across in the Bentley manual was that you shuld shift to tranny into 6th gear to provide extra room when trying to get the slave cylinder pushed into the bell housing.

Great write-up Jay!

[jaybquick@JHM]

Jay thanks again for the tip on the gravity bleed procedure.

BTW, I got the boot out with the pushrod! I only had to disconnect the axle and remove the driver side trans support.

BTW, another useful tip that I came across in the Bentley manual was that you shuld shift to tranny into 6th gear to provide extra room when trying to get the slave cylinder pushed into the bell housing.

Great write-up Jay!

Yeah, I always push it back, just out of habit. Been workin on cars so long I take tricks like that for granted when i do them and forget to relay the information.


Glad to hear the pushrod came out with the boot. They usually do unless the boot was ripped previously.

[jaybquick@JHM]

IMPORTANT TIP New as of 5-11-09
We have found that if you try to bleed the clutch with the car NOT completely level. Like if you just jack up the front. You will almost NEVER be able to bleed it completely or will make it take forever. This traps air bubbles in one of the upper corners. So make sure the rear of your car is level with the front of your car and if not level even a little higher than the front. The key is to not have the front higher than the rear. We have always bled ours when the cars were level and routinely do it in 5 minutes or so. Well recently I was lazy and tried to do one with just the front of the car up and I couldn't get it to bleed for me no matter what I did. I thought about it and it hit me why. So I jacked the back of the car up and BOOM, it bleed quickly. Hope this new tip helps some that are struggling.

[blmlozz]

I usualy use my power bleedr which gets it there to about 95% which usualy means about .5-1" of soft travel and then good engagement, even from bone dry systems. Could never really get it to be 100% with the bleeder

[jaybquick@JHM]

Power bleeders are always a nice helper to speed up the process.

[sleeperwagon]

question for you guys. This part is $130 and is a 3 hr job at most shops (@ $75 per hour is $225). It sounds like a pain in the ass to try and save $225 plus the risks outweigh the gamble. Whats your thoughts IF you had the $225 to spend???

[Tokin]

I would buy two slave cylinders for the same $120 (@purems) and you have a backup in case you mess up. Then you can return one and save yourself > $250 because this really isn't a crazy hard job.

[jaybquick@JHM]

question for you guys. This part is $130 and is a 3 hr job at most shops (@ $75 per hour is $225). It sounds like a pain in the ass to try and save $225 plus the risks outweigh the gamble. Whats your thoughts IF you had the $225 to spend???

We have them in stock for $55 each. It is not a 3 hour job if the shop knows Audis. More like 2. But at least you can buy the part for less and have it done.

http://www.jhmotorsports.com/shop/ca...products_id=88





Master cylinders in stock as well --> http://www.jhmotorsports.com/shop/ca...products_id=89

[DxC]

sigh i just bought 2 of these for 70 on your site, now theyre 55

[jaybquick@JHM]

sigh i just bought 2 of these for 70 on your site, now theyre 55

Sorry man. We are just trying to stay in line with others pricing.

Call us before you order next time and we will see what we can do to make up for it.

Thanks.

[slkdik]

hey just wondering what hose on the fluid resivior goes to the slave? looking at the resivior i see one on the driver side that is just below the MIN mark, and another hose on the pass side but lower on the res. i think i need to bleed my slave as my clutch has stopped disengaging. my fluid is currently sitting between min and max, and unfortunately where i live on sundays nothing is open. im wanting to try and bleed it today but not sure how much fluid ill lose. looks like if slave line is the higher hose on the driver side then it (the fluid) may drop below which would ultimately make things worse.

would i be better off waiting till tomorrow before i do anything with it?

[mholme]

Just wait until you have fluid. When you bleed it, you're going to need to not let the level dip below the hose by topping it off as you go, or you'll suck air into the slave and have to do it all over again.

[jaybquick@JHM]

The hose is on the side closest to the drivers side on the reservoir, just below the minimum mark. It would be best to wait until you have fluid though.


We have slave cylinders, master cylinders and fluid in stock. http://jhmotorsports.com/shop

[S4-Casa]

JHM !
How on gods green earth do you get the clutch slave on with the updated shifter linkage?
I am having a hard time just try to align it to get it all in... any other tricks?
I put it in 6th, its lubed, and its not aligning to get in all the way... it hits the upper side of the shifter linkage so I cannot get it back in... everytime I go in sideways left right it stops at the hard plastic of the cluch slave to the opening. I cannot go back and forth since it hits the linkage.... I am soo confused...

Updated :

I had to drop the subframe - remove the "updated" solid shifter linkage and then install the Clutch Slave...
This makes its it a whole lot easier to do... Hope this helps others in the same senario...

[mholme]

Just did this today after putting it off for months. Wasn't that bad, but now I'm at a crossroads. I installed a new cylinder with the bleeder valve open and a line connected ready to bleed. It went in very easily because of this, pretty sure it's lined up on the fork. The pedal is ROCK hard right now after bleeding and closing everything up..I hope this is normal, I didn't go ahead and press the clutch with my foot because I was wanting someone with a stock clutch setup who has done this to confirm that that amount of resistance is normal..before I end up punting the pushrod out of the slave.

[slammed_nogaro]

nice write up... im replacing my master cylinder 2marro.... hopefully it will solve my issue... its kinda weird... so lets say im driving on the highway for like 5 miles and dont touch the clutch and just kept it in 6th, so lets say im pulling up to a tollbooth and have to down shift and i push my clutch and it goes down and it almost get stuck all the way down but come up half way up and barely works... like barely pushes the pressure plate to change gears, then i pump the clutch and it gets stiff again and pressure all the way through the motion i guess ahha... so basically if im driving around town and always using the clutch its pretty much fine still feels a little weird but works, then if im on the highway and dont touch it for a while, then have to use it, it once got stuck at the floor and i had to pull it up with my hand and pump it till it gets hard again... if you have any advice i would appreciate it... wow feels like i just wrote a novel

[jaybquick@JHM]

JHM !
How on gods green earth do you get the clutch slave on with the updated shifter linkage?
I am having a hard time just try to align it to get it all in... any other tricks?
I put it in 6th, its lubed, and its not aligning to get in all the way... it hits the upper side of the shifter linkage so I cannot get it back in... everytime I go in sideways left right it stops at the hard plastic of the cluch slave to the opening. I cannot go back and forth since it hits the linkage.... I am soo confused...

Updated :

I had to drop the subframe - remove the "updated" solid shifter linkage and then install the Clutch Slave...
This makes its it a whole lot easier to do... Hope this helps others in the same senario...

We just undo the 13mm nut and slide the linkage off the selector shaft. Then you have room. You don't have to undo the whole thing.

Also we alwasy take the drivers cv boot shield off of the trans to give more room. We never have to lower the subframe.

Just did this today after putting it off for months. Wasn't that bad, but now I'm at a crossroads. I installed a new cylinder with the bleeder valve open and a line connected ready to bleed. It went in very easily because of this, pretty sure it's lined up on the fork. The pedal is ROCK hard right now after bleeding and closing everything up..I hope this is normal, I didn't go ahead and press the clutch with my foot because I was wanting someone with a stock clutch setup who has done this to confirm that that amount of resistance is normal..before I end up punting the pushrod out of the slave.

Sounds like you may have missed the fork if it is ROCK solid. One more push and it will most likely pop out.

nice write up... im replacing my master cylinder 2marro.... hopefully it will solve my issue... its kinda weird... so lets say im driving on the highway for like 5 miles and dont touch the clutch and just kept it in 6th, so lets say im pulling up to a tollbooth and have to down shift and i push my clutch and it goes down and it almost get stuck all the way down but come up half way up and barely works... like barely pushes the pressure plate to change gears, then i pump the clutch and it gets stiff again and pressure all the way through the motion i guess ahha... so basically if im driving around town and always using the clutch its pretty much fine still feels a little weird but works, then if im on the highway and dont touch it for a while, then have to use it, it once got stuck at the floor and i had to pull it up with my hand and pump it till it gets hard again... if you have any advice i would appreciate it... wow feels like i just wrote a novel

Sounds like a hydraulic problem for sure and the slave causes this 95% of the time. So if you swap that out and still the same problem just change your master, but the slave should be it.

Good luck.

[mholme]

Sounds like you may have missed the fork if it is ROCK solid. One more push and it will most likely pop out.

Nope..Something else entirely. One more push and I don't doubt it will pop, but something else is wrong inside. Transmission is coming out this weekend..

[imola]

Nice, thanks! You rock with your write-ups and videos

[S4-Casa]

We just undo the 13mm nut and slide the linkage off the selector shaft. Then you have room. You don't have to undo the whole thing.

Also we alwasy take the drivers cv boot shield off of the trans to give more room. We never have to lower the subframe.


I did this but in order to remove the shifter linkage you have to remove the bolt on the passenger side of the tranny (the cross holder) and to get to that you need to lower the subframe no?

[jaybquick@JHM]

I did this but in order to remove the shifter linkage you have to remove the bolt on the passenger side of the tranny (the cross holder) and to get to that you need to lower the subframe no?

If you push the selector shaft all the way in towards the passenger side and put it in gear before you loosen it then you have enough slack to slide it off. Or you can undo the large bolt and nut that holds it together.

There is no need to undo the crossrod. Hope this helps you in the future.

[joe dub]

wanted to bump this thread, it helped me out, but I want to add a few things I figured out in the process.
1. for anyone replacing their slave, pull the line off first, I tore the rubber stretching mine once the slave was out of the housing, and replacing the line was way worse then replacing the slave.
2. on the new slave install, do not hook up the hydraulic line until the slave is mounted on the housing. this will make it easier for you to compress the slave.
3. install the slave from the top of the car, this was easiest for me, I do have fairly long arms, but with the car sitting on the ground and the coolant resovoir moved out of the way, it is much easier then laying under the car trying to reach around the axle.
4. this may sound ridiculous, but when you're pushing the slave into the housing, make sure your work place is quiet (no music) so you can hear if it is hitting the clutch fork and pushing the air back out where the hydraulic line hooks up. On my first slave replacement attempt i missed the fork and blew the piston right out of my brand new slave. ***If you are missing the clutch fork, you will feel the bumps of the rubber boot on the slave going over the fork.
5. bleed the slave from the top also, with the car down. follow bleeding tips above, gravity bleed etc..

I think thats it, hope it helps someone

[J-b5]

And wear long sleeves ^....

trust me.

[sparky17]

I have to revive this from the dead and also recommend it be moved to the Tech section since it's an extremely helpful thread. I'm hoping someone can help me figure out whats going on with my clutch bleed I created a new thread before but noone was of help I'll try again in this thread. First I installed a brand new Southbend Stage 4 Clutch with a USP Metal Slave with braided stainless line and a brand new Clutch Master Cylinder. I've followed the directions above and the pedal is getting better however it's still slow to return to its normal position. The slave cylinder is working as it does engage the clutch and when I'm bleeding I only see fluid coming out and no air. I have the car perfectly level and I've already gone through 2L of ATE Super Blue DOT4 Brake Fluid and it's extremely frustrating. I've used a power bleeder at 22psi as well and still no help. Anyone with any ideas? The pedal now has stayed the same after 3 times of trying to bleed it comes back up to the normal position but doesn't have that kick back that it's supposed to.

[DrmCtchr]

Ok I have a B7 RS4 (07) I dont have access to a FSM. So i f someone one could quickly explain where the slave cylinder is and how to get to it, it would be helpful

I have the new slave here ... but i dont see where it lives.

Thanks in advance,
David

[BlkdoutS4]

Ok I have a B7 RS4 (07) I dont have access to a FSM. So i f someone one could quickly explain where the slave cylinder is and how to get to it, it would be helpful

I have the new slave here ... but i dont see where it lives.

Thanks in advance,
David

Might want to try over in the B7 forums...

[sCeRaXn]

One thing that i learned will make things a lot easier is to leave the old slave in the car until youre ready to put the new one on(just unbolt and set to the side). Now go ahead and fill up the new slave and bench bleed it to get out as much air as possible, then take a vac cap and use a small needle or pin to make a little hole in the end of it and place it over the hole on the slave where the line connects to it. Now go ahead and slide the pushrod onto the fork and slowly press it into place. While doing this the excess brake fliud will come out of the hole you made in the vac cap. Once its aligned properly go ahead and bolt it down and then quickly remove the line from the old slave and install it on the new one. Doing it this way allowed me to get all of the air out in literally 5 minutes, but most importantly it made the installation of the unit so much easier than the other times when i went ahead and connected the line before installing it. Hope this helps.

[wednesday]

I couldn't find a thanks button and understand that this is a really old thread. I just wanted to say, thank you. After breaking one slave cylinder, I understand this lot more after reading this thread. I had not read this thread when I broke mine. I guess best way to learn is the hard way. Thanks again.

[arab06]

so i saw that a guy said replacing it from the top would be the easiest. did you have to move anything. how did you see it and know what you were doing. my car is not drivable and its my dd so i have to get this done soon. or does anyone else have any ideas on how to do it because i spent about 4 hours trying just to get to it so i can remove it but i didnt have any luck at all. anyy ideas?