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Hydraulic clutch bleed problems, FZ750

Discussion in 'Technical and Troubleshooting Torque' at netrider.net.au started by linerunner, Nov 10, 2006.

  1. OK. This morning the friction point had moved to about half a cm from the bar, if that, which I dont much like. I pumped them (quite a) few times and the friction point moved back to where it should be but after the bike had been sitting for awhile (at work), when I went back to it the friction point was back at the bar.

    How could this happen? How can it move around so freely?
    Obviously I need to bleed it, but Ive had trouble in the past. I took it to a dealer and they replaced the plates and told me that they couldnt get it to bleed properly (they also replaced the master cyclinder (from a wrecker) and installed a new piston and seal in there because they thought that this was the reason it wouldnt bleed). This was the problem that Id had myself, which was why I took it in in the first place. There was just air coming out with the fluid when I pumped them and I'd originally gone through about a litre of fluid and there was still loads of air. So I took it in.

    They said that they had fixed it by using a syringe to pump the fluid in through the master cyclinder. I have a syringe at home which I bought especially, in case I had problems down the line (here I am). No I am not a junkie, in case you are wondering.

    Im afraid that if I bleed them I might make it worse. Someone told me that if air gets in the clutch you need a vacuum pump. I use this bike to commute so I cant afford to have it off road for too long so I want to know as much as I can before I do anything.

    Does anybody have any advice/suggestions?
  2. air must be getting in somewhere,
    if the clutch master cylinder has checked out ok
    have you checked the slave cylinder and hydraulic hose
    for leaks, including the copper washers sealing the hose to the
    slave and master cylinders!!

    the hydraulic hose isn't expanding in the heat
    causing these problems is it??
  3. Hmm I thought so but I cant figure out where... Without replacing everything or taking parts off Im not sure what to do...

    Do I really need a vacuum pump to bleed them or was the guy who told me just full of it?

    When I bled the front brakes there was some fluid coming out where the bleed nipples/valves screw into the caliper, so the fluid was moving past the thread. I have some spare bleed valves so maybe I should replace them for the clutch, maybe thats where the air is getting in. The fluid only came out when I was actually doing the bleeding, so pumping the levers, when I tighted them up the leak stopped. So I didnt much worry about it...

    thanks blackgixxer tho, Im going to go and inspect every part trying to find some liquid escaping or some tears or nicks, so thats a start...

    What my major concern is, is that if I try and fix it, I might make it worse, so what do you guys reckon? Do you think from what I have told you that it would be safe to have a crack at it? Theres nothing major wrong with it?

    Thanks guys...
  4. Firstly... you may have been misinformed or just misheard the advice. If your having trouble bleeding a system it's quite often easier to fill it from the bottom of the system using a syringe. In this case you fill it from the slave cylinder (down by the clutch end of the system).
    No you don't need a vacuum pump to bleed them; that's a load of BS.
    I'd drain the entire system, then fill it from the bottom using a syringe and see how you go.

    One other thing to keep in mind is the condition of the lines. If they're at all old, damaged or scuffed then they may have a very slow leak which is letting in air or letting out hydraulic (brake) fluid.
  5. Thanks koma,
    finally someone tells it to me straight! Damn dealers...
    I bled them today and I think I got all the air out this time... Ill see how it feels in a week tho...