Clutch Salve Cylinder Bleeding

18219 Views 20 Replies 6 Participants Last post by  J13ME X
Clutch Slave Cylinder Bleeding

Anyone done this before and have some tips? Been watching the following youtube clip but not sure how you go about compressing the piston.

Do you:

1. Disconnect the fluid line and clutch linkage
2. Remove the slave cylinder
3. Compress the piston to evacuate the fluid while its off the car
4. Keep the piston compressed with retracting tool like they have in the video and reconnect fluid line
5. Bleed the fluid through the bleed nipple until free from air
6. Release the piston from the retracting tool so it draws fresh, air-free fluid into the chamber
7. Re-fit slave cylinder and reconnect clutch linkage

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easy job,

undo the old one take it off if replacing it its best to unbolt it first then disconnect the pipe, make sure you have the washer on the end of the plastic insert and not still stuck in slave.

If you are just bleeding it, unbolt it, leave the pipe connected, use an easy bleed kit and hold the slave at 45° with the bleed at the highest side, open the nipple so fluid starts to flow with the easy bleed on, then using your hands slowly compress the slave and slowly release it, do this 5 times and the lock of the nipple, you can then push it back into place. using the system of holding it back with a tool rarely works as air still stays in the system
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So is the fluid line flexible? Thats what I wasn't sure about whether the slave needed to be removed or not.

So is the piston not physically attached to the clutch linkage? Just a case of unbolting the slave cylinder and it comes away?

I don't have an easy bleeder, was planning on 2-man'ing it. I can see this being a bit of a bitch without one as I'd need to hold the slave, open and close the nipple as well as compress/release the piston.

If using an easy bleeder would I not need to lock the bleed nipple before releasing the piston again?
Go and get an easy bleed as the clutch bleed is not that easy doing the two man method. With the easy bleed you can lock off the nipple either with the piston out or in once you have done the 5 pumps.

The pipe is solid but there is a rubber line above the gearbox so you can flex it

If you do the two man method you will find you need to push the piston in at the same speed your friend puts his foot on the peddle and you need to lock the nipple off before you release the piston and it then becomes a ball ache of a job. you will find you will be covered in brake fluid this method and the nipple on the slave is hard to hold and its also plastic

The clutch arm will not move from where it is and its only resting against the slave piston. once you have locked off the slave nipple to fit push the end of the slave against the clutch arm and compress it and push the slave home, its very easy, just like winding a brake piston back
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Ok so

1. Unbolt slave cylinder
2. Connect easy bleeder
3. Crack open bleed nipple
4. Compress/release piston 5 times
5. Lock bleed nipple with piston compressed
6. Remove easy bleeder
7. Refit slave cylinder

That sound about right? Still a bit fuzzy about the piston pump bit, won't i need to lock the bleed nipple when releasing the piston to avoid drawing air back through?
Thats all right there.

Easy bleed is fed from your tyre pressure so there is no draw back unless you let go fast with the piston. with an easy bleed you do not have the issue of the piston drawing air back.

Done it many times and never had it draw air back when doing it that method, so long as your not fast letting the piston out it will draw from the fluid side and not the air. Also do not forget the to draw air the piston needs to draw more pressure than the easy bleeds 32psi

if your worried about air being drawn back put some fluid in a jar then put the pipe from the nipple into the jar that way if it does draw back it will only pull fluid however its not needed
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Nice one fella, thats cleared it up, ta muchly.
Well had a go at this earlier, didn't go well at all. Unbolted the cylinder pretty easy, cracked open the bleed screw, connected the pressure bleeder to the spare tyre pumped to 30psi (says 20 in the instructions but meh), pushed in the piston aaaaaand....nothing, not even a tiny bit came out of the bleed screw...

tried compressing and releasing the piston a few more times but was doing fuck all, piston was pretty hard to push in and I was just thinking 'WTF? Where is it going!?'. The only explanation I can think of was there wasn't enough pressure from the easy bleeder so it was just pushing the fluid back up?? But still nothing after I pumped the tyre up more..

Pushed the clutch pedal down and fluid came out then (fluid was green as well? stock stuff was red before I bled the brakes??) but then obviously as I didn't close the bleed screw its drawn air in so now the peddle feels like stepping in dog shit. fffuuuuuuu, any ideas?
Right sounds like you got into a bit of a mess. Clearly something was not right how about I PM you my number and you call it...
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Bleeding the clutch was the only problem we had when doing my gb change, Dave did it first time with a pressure bleeder but rather than one you connect to a tyre it was a powered one. Next time it had to come off Rich did it easily with the pressure bleeder but we couldnt do it by pumping the pedel like with brakes.
yeah would be good rich, halfway through i was thinking "i really wish i had rich's number right now"..

what threw me was how even with the bleed screw open, compressing the piston didn't push any fluid out...?? surely its the POS easy bleeder not putting enough pressure into the master cylinder?
Nah man the easy bleed is simple as can be, always does what it should. chances are the nipple wasn't out far enough for 30psi to do anything, you almost have to take it out before it bleeds off the easy bleed
Ok ill have another go with the bleed screw threaded almost out but turning it more and more earlier didn't seem to make a blind bit of difference. What was happening to the fluid when I was compressing the piston with the easy bleeder on though? What pressure do you usually have the tyre at when you do yours?
the nipple will be out nearly 5mm, I do use 30psi or standard tyre pressure, however when you use your foot your more like 5Bar going through so double that of the easy bleed.

There is a straight flow from the easy bleed through the the slave with nothing in the way which will stop it. I assure you if you take the nipple out further your world will be much brighter

I think before you do it again pick the phone up and I will walk you through it
ok cheers chief, bit of a shit having to buy a whole tin of fluid just to do the tiny amount that the clutch system takes, may as well just bleed the brakes again :laugh:
I just leave the slave attatched. Compress this piston with it on and use something to stop it coming back out, i just used a pry bar. Then just did a normal 2 person bleed.

If theres still a tiny bit of play in the pedal leave it over night, usually they will burp it up. I left mine like that and it was working fine within a few pumps.
yeah pedal travel has reduced but it feels like absolute aids
oh and i feel the slave cylinder itself may be letting by slightly, when I pushed the piston back in to refit last night fluid kind of spurted out from the boot, it was fine when I had it at an angle when i was trying to bleed but once turned back to face the clutch actuator and pushed in to fit I had some fluid leak out and down my arm...thats another £25 odd quid out the pocket
Just in case anyone has issues with this, the angle of the dangle (hold at 45 degrees) is vital! Still had air in mine until I got that right.
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