Page 1 of 2 12 LastLast
Results 1 to 20 of 29

Thread: Bleeding your hydraulic clutch

  1. #1
    Retired Posh Johnny's Avatar
    Join Date
    Jun 2007
    Location
    Nantwich
    Posts
    809

    Bleeding your hydraulic clutch

    Hands up who has had or is having hydraulic clutch or rear brake problems.

    OK hands down, I think that is all of you, so here goes a step by step guide to cure your woes
    The problems on the clutch are caused by vertical layout and the small displacement of fluid by the master cylinder. On the rear brake the volume displaced is smaller still.

    It is virtually impossible to properly bleed a motorcycle clutch or front brake using pump the lever and crack the banjo method. Vacuum systems are a much more capable method, but their cost outweighs the advantages for part time mechanics.

    Here we have a method on a budget simply using a plastic medical syringe, of from 10 to 75 ml, you can use reverse fluid injection to effectively bleed any motorcycle brake or clutch in very little time.

    Ensure your reservoir is clean and free from contaminates (pumping dirt into your lines is not good). Extract all the fluid out of the reservoir and clean. Take your clean syringe and fill it with new brake fluid. Attach it with a clear vinyl tube to the bleeder at the caliper or clutch slave. Open the bleeder and inject the fluid while watching the level in the reservoir. Stop when full. Close the bleeder. Suck out the reservoir and repeat as needed. Job done, how easy was that .






    One last thing about bleeding clutches. There is not actually a bleeder on the slave cylinder itself. It is part of the banjo bolt. it is possible to bleed and still have a pocket of air within the slave cylinder. It is however easy to remove it.

    After bleeding as above and filling the reservoir, remove the three screws securing the slave cylinder. Remove the cylinder and hold it in its normal attitude then tip it slightly to the right (as if you were leaning the bike to the right). Allow the internal spring to slowly push the piston out 5 or 6 millimeters and push it back in forcefully. Be careful not to spill any fluid on your paintwork. Repeat this several times. Reinstall the cylinder you may want to reverse inject just for good measure. (do not overfill your reservoir, when hot it expands and can cause a slipping clutch)


    Tada









    Article kindly used with permission from KZmille (Author)
    Last edited by Posh Johnny; July 1st, 2007 at 01:55 PM.

  2. #2
    Baby Twin 77rons's Avatar
    Join Date
    Jan 2008
    Location
    scotland
    Posts
    19
    superb.
    just bought my '03 mille.
    talkin to a guy earlier that pointed to my clutch reservour and said the previous guy had 'burned the clutch' as it was almost black.
    can i use your method to repair this damage or is more work needed?
    just replacing the fluid enough?

  3. #3
    Super Moderator OldTLSDoug's Avatar
    Join Date
    Jul 2007
    Posts
    47
    Clutch isn't burned. nor can it be diagnosed by the color of the fluid. It is only pushing on a rod that goes to the clutch. The black fluid is a result of moisture and the seal and the little black hose. Bleeding an flushing will fix it, possibly replace the seal. The guy you were talking to should not be allowed to work on your bike.

  4. #4
    One Liter Duc Eater DaveRSV's Avatar
    Join Date
    Nov 2007
    Location
    Northampton
    Posts
    831
    Quote Originally Posted by Posh Johnny View Post
    There is not actually a bleeder on the slave cylinder itself.
    This is obviously something that Aprilia has remedied as I have bleed nipples on both the master and slave cylinders of the clutch.

  5. #5
    Super Moderator OldTLSDoug's Avatar
    Join Date
    Jul 2007
    Posts
    47
    I just finished the kzmille method and it is absolutely spot on. I am truly impressed, here is my story.

    I bought a syringe for $0.89, I had a quart of brake fluid. I bought the new seal locally, for $22.37. I read this entire post and the bulletin kzmille posted and spend some time trying to find some "silicone o-ring grease" Finally got it at Loews for $2.99 or so.

    Moment of truth, I sucked the reservoir dry with the syringe, then sucked the slave and the line down via the bleeder. I popped off the slave cylinder and saw the muck and goo. I lubed up the new seal, filled the slave with brake fluid, inserted the piston and pushed it until the thing was in far enough to raise the level in the reservoir. Then I pressure filled it from the bleeder bolt for about 3 cycles. Then I pulled the slave off and pumped it hard 5 times, then bolted it back, pressure bled it 3 or 4 times more, then pulled it off and did 5-7 more compressions. Then I bolted it back on, filled the reservoir to the middle. I fired up the bike, and the clutch felt way too light to be working, so I gingerly put it in gear and WOW! It works perfectly. I took a short spin and I would say the lever effort is 20% less and it is much smoother. So, my hat is off to kzmille. I made the tool for the rear brake shown in the service bulletin today, and tomorrow I plan to bleed it out. Much easier than even using the Mity-Vac. Thanks for the simple method for a simple old guy.

    Here are a couple of pictures, click the picture for a big 'un

    dirty slave cylinder. It was perfectly smooth and not marked at all after I cleaned it.



    Here is the piston, note the black crap, it was easily wiped off, but it was the residue from the seal breaking down and cleaned up nicely.



    The end of the piston where the clutch pushrod goes.



    Finally, the spacer and the clutch pushrod.


  6. #6
    Superbike Twin richmond rossi's Avatar
    Join Date
    Jan 2008
    Location
    Middlesbrough
    Posts
    204
    Looks straight forward enough, shall have to try that, thanks.

  7. #7
    One Liter Duc Eater Sabre's Avatar
    Join Date
    Feb 2008
    Location
    Devon
    Posts
    804

    Talking

    Quote Originally Posted by OldTLSDoug View Post
    The guy you were talking to should not be allowed to work on your bike.

    PMSL but very true.

    BTW KZMille - he de man

  8. #8
    Baby Twin
    Join Date
    Apr 2009
    Posts
    20

    (almost) Black clutch fluid...

    I think itís the time to change my clutch fluid, as it is almost black!

    I was scanning the forum and found this thread, which seems to go right to the point!

    ...however I still have a few questions. It will be the first time I change either the clutch or the brake fluids, so I want to be 110% sure of what to do in order to avoid mistakes

    I was familiar with another (the "classical" ?) method for changing the liquid in the hydraulic clutch or brake system.

    1) Wrap a piece of cloth around the reservoir in order to avoid any spills, open the reservoir and remove the seal. Using another piece of absorbent cloth suck the reservoir dry of the old fluid.
    2) Add the new fluid up to the max level and close the reservoir.
    3) Open the bleeder (in the brake calliper or clutch) and attach the clear vinyl tube to the bleeder and the receptacle for the old fluid.
    4) Pump the brake or clutch lever until the fluid coming out through the bleeder and vinyl tube is the new one. Detach the tube and close the bleeder.
    5) Finally, top up the level of fluid in the reservoir as appropriate.

    I was taught this method would insure no air would slip into the system? Now I am somewhat unsure how to change my clutch fluid, especially as I read plenty about Mille clutch and brake problems connected with air bubbles getting into the systemÖ!?! Can someone help out with this? Thanks a lot!

  9. #9
    Dolenc
    Guest
    Some people do it the standard way, but they also open the bolt on the master cilinder to get all the air out, it can be done, but you have to know what are you doing

    Using the pringe is easyer and it works

  10. #10
    kawasakiinit
    Guest
    Quote Originally Posted by Spidracer View Post
    I think itís the time to change my clutch fluid, as it is almost black!

    I was scanning the forum and found this thread, which seems to go right to the point!

    ...however I still have a few questions. It will be the first time I change either the clutch or the brake fluids, so I want to be 110% sure of what to do in order to avoid mistakes

    I was familiar with another (the "classical" ?) method for changing the liquid in the hydraulic clutch or brake system.

    1) Wrap a piece of cloth around the reservoir in order to avoid any spills, open the reservoir and remove the seal. Using another piece of absorbent cloth suck the reservoir dry of the old fluid.
    2) Add the new fluid up to the max level and close the reservoir.
    3) Open the bleeder (in the brake calliper or clutch) and attach the clear vinyl tube to the bleeder and the receptacle for the old fluid.
    4) Pump the brake or clutch lever until the fluid coming out through the bleeder and vinyl tube is the new one. Detach the tube and close the bleeder.
    5) Finally, top up the level of fluid in the reservoir as appropriate.

    I was taught this method would insure no air would slip into the system? Now I am somewhat unsure how to change my clutch fluid, especially as I read plenty about Mille clutch and brake problems connected with air bubbles getting into the systemÖ!?! Can someone help out with this? Thanks a lot!

    did mine yesterday following the above only thing not mentioned above is the bit where you have to open the bleeder on the master and pump it slowly to get air out (that was done after every thing else) . maybe i did something wrong in the first bit but that got it sorted anyway . seems fine on a 2 mile test run will give it more when not at work/weather .

    i am a real novice mate and was amazed i did it . plenty of cloths around everywhere also

    give it a go whats the worse that can happen ? people on here will help you if it goes wrong

  11. #11
    Baby Twin
    Join Date
    Apr 2009
    Posts
    20
    ...Right!

    Just got 0.5 litres of Ferodo DOT 5.1 brake fluid (bit expensive but hope it will last for a reasonable period before it gets black...) so I think this weekend after my Sunday morning blast I will give it a try and change both the clutch and the front brake fluid (the later is now in a "dark honey" hue...), as I understand once the brake fluid container is open it will deteriorate by absorbing moisture from the air... (...the hygroscopic part of the story...).

    ...Still undecided whether to use the syringe at my first attempt at the operation...

    ...By the way, the clutch master cylinder doesn't have a bleeder nut and bolt like the front brake one! So unlike the later I cannot use this to extract any (eventual) air bubbles from the clutch circuit... ?

  12. #12
    Baby Twin
    Join Date
    Apr 2009
    Posts
    20
    Quote Originally Posted by kawasakiinit View Post
    did mine yesterday following the above only thing not mentioned above is the bit where you have to open the bleeder on the master and pump it slowly to get air out (that was done after every thing else) . maybe i did something wrong in the first bit but that got it sorted anyway . seems fine on a 2 mile test run will give it more when not at work/weather .

    i am a real novice mate and was amazed i did it . plenty of cloths around everywhere also

    give it a go whats the worse that can happen ? people on here will help you if it goes wrong
    ...Excellent! I will nag you plenty then!

    ...the worst that can happen? ...err...a slipping clutch?

    ...and for the brakes: ...a spongy feeling at the lever with extended brake distances?

  13. #13
    Baby Twin
    Join Date
    Apr 2009
    Posts
    20
    ...and by the way: "novice" with 25 years riding experience ?

    ...but seriously: thanks a lot in advance! (when I post a "HELP NEEDED!!!" message asking how to recover my brakes and clutch from my catastrophic attempt...)

    ...I am more and more reaching the conclusion that if I want to have my mechanical work well done I will have to do it myself!!!

    Just two examples: two services ago the mechanic (from a local official Aprilia dealer) forgot to change the o-ring when changing the oil filter cover to the later "upgraded" one accordingly. The result: a rear tyre spraied with engine oil on its left side and one of my most unpleasant experiences on a motorbike...

    in the last service the mechanic (another one) added too much engine oil (sure: there aren't oil bottles of 3,9 litres...): the result? Last week when I opened my airbox there was a nice "oil bath" in there

  14. #14
    Baby Twin
    Join Date
    Apr 2009
    Posts
    20
    ...KZmille and Posh Johnny are "THE MAN"!!!

    The syringe rules!

  15. #15
    Baby Twin
    Join Date
    Aug 2007
    Location
    Birmingham, UK
    Posts
    49
    I'm going to have a go at this as my clutch is so bad that I'm not even sure I can get it to the bike shop to get them to sort it. I tried riding it this morning, stalled on the drive 3 times putting it in gear and then decided to give it up. I can get it going but I think I might need to do some remedial action just to be safe.

    My question is this the bleeder valve is at the clutch slave cylinder, so where's that then? I'm assuming that this is not the nipple on the bar next to the lever but is somewhere down inside the fairing? Or is it?

    Also my friend has a pump for doing brakes which he says could be used. Any tips on doing it with that?

    Cheers

  16. #16
    Dolenc
    Guest
    I would recomend you take it to the bike shop, its cheap and if you dont know what are you doing, its safer

  17. #17
    One Liter Duc Eater heroblob's Avatar
    Join Date
    Jan 2008
    Location
    Essex
    Posts
    596
    I can give you a quick fix that will last a while.
    You will need a spanner to crack the bleed nipple at the master cylinder on the handle bar and a few pieces of tissue.
    Crack the bleed nipple at the master cylinder, and place the tissue around it.
    Now for the important bit. VERY SLOWLY squeeze the clutch lever JUST enough until you feel it take up the play. now squeeze it approx a couple of mm still very slowly and watch for an air bubble at the nipple. when you get all fluid nip the nipple and release the lever. repeat until you get no air bubble.
    I emphasize the slow and small movements as if you are hand fisted you will spray a jet of break fluid out all over your paint work. Not good.
    Be gentle and this works. got me out of the shit when i was away in Wales last year, Prior to getting my MPL slave cylinder. Worked a treat. Just keep an eye on your reservoir level.

  18. #18
    Baby Twin
    Join Date
    Aug 2007
    Location
    Birmingham, UK
    Posts
    49
    Quote Originally Posted by Dolenc View Post
    I would recomend you take it to the bike shop, its cheap and if you dont know what are you doing, its safer
    Lol a wise suggestion. Actually my dad does know what he's doing so I'm going to get his help at the weekend so that's why i just wanted to make sure.

    The bike is booked in on Monday anyway so if i can get it there I'll just wait. It's just that based on this morning getting it there is going to be a bit hairy!

  19. #19
    Baby Twin
    Join Date
    Aug 2007
    Location
    Birmingham, UK
    Posts
    49
    Quote Originally Posted by heroblob View Post
    I can give you a quick fix that will last a while.
    Cheers Heroblob. If nothing else I may at least be able to get it to the point where the clutch fully engages/disengages. At the moment if it's in gear it's rolling forward which is fine on the move but a bit hairy in traffic.

    Thanks a lot.!

  20. #20
    One Liter Duc Eater heroblob's Avatar
    Join Date
    Jan 2008
    Location
    Essex
    Posts
    596
    The amount of air in the system is minimal. I had only had to do this the once, and it worked a treat. gave me back a fully functioning clutch which lasted the 4 months up until i fitted the MPL slave. the other thing you can try is cable tying the clutch lever to the bar and leave it over night. allows air to pass up into the reservoir. the problem appears to be that the reservoir hose is not the highest point, so allowing natural bleeding. the bleed nipple is higher which is why is is easy to bleed as described before.

Page 1 of 2 12 LastLast

Similar Discussions

  1. bleeding hydraulic brakes and clutches
    By w00dzy in forum Motorcycle Talk
    Replies: 8
    Last Post: February 11th, 2013, 01:55 PM
  2. Replies: 17
    Last Post: November 27th, 2012, 08:31 PM
  3. Clutch Bleeding
    By reigo in forum Aprilia RSVR
    Replies: 1
    Last Post: June 16th, 2011, 06:20 AM
  4. Bleeding clutch?
    By andirsv in forum Aprilia RSVR
    Replies: 11
    Last Post: June 7th, 2009, 05:10 PM
  5. clutch bleeding
    By richtee0 in forum Aprilia RSVR
    Replies: 9
    Last Post: May 7th, 2008, 02:58 PM

Search tags for this page

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •