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Brake bleeders...what the hell to use?

Discussion in 'Bling and Appearance' started by blue, Jul 27, 2006.

  1. I tried to manually bleed my bike few months ago but oh boy.. big mistake.. took 4 days of pumping and shifting handlebars to get all the air out. not joking almost 3 hrs everyday over 4 days. just didnt wanna give up and go to the mechanic. ego wont allow it. My right forearm is stronger than ever though :grin: .
    So I need to know what shall I use the next time around? one-way valve bleeders( apparently not effective on bikes), speedbleeders, vacuum bleeders or vacuum bleeders with guage etc etc. shouldn't be too expensive. What type of grease do you need to use around the bleed nipple threads before opening them for a tight seal.. can you use petroleum jelly or any grease?

    Your opinions will be really appreciated. I got better uses for my right hand.
  2. Bloody hell mate, you must be doing summat wrong lad.

    You use a one way tube, drain it into jar or similar container.

    Just squeeze the brake lever to push fluid and or air down the tube.

    That's it.

    The other way is to unscrew the nipple cap, squeeze the brake lever,(once only) hold it closed, do the nipple cap up before releasing the brake lever.
    You should only need to this two or three times.

    Grease around the nipple threads? The fluid comes out of the top of the nipple, what do you need grease for? You don't have to undo the nipple cap all the way, just enough that fluid will come out.

    I assume there was enough fluid added to the resovoir that no air got into the line that way?
  3. Some bike models are notoriously hard to bleed, mine will usually take 30 minutes of pumping the conventional way, so this is what I do now...

    Buy a large plastic syringe that you can whack some tubing onto and connect this to the nipple. Draw some fluid into the syringe, then tighten up the nipple, this should save you quite a bit of time and hair pulling.

    Once bled, I pull the lever back to the bars with a rubber band or similar overnight. This allows any small/trapped air bubbles to rise up to the master cylinder under the pressure. This really does work well.

    A final quick bleed in the morning to make sure you have every last bit of air out, and then you should have a rock hard brake lever with the minimum travel.
  4. Sometimes, after you have done the rubber band overnight trick, you find that the air is trapped in the highest point of the system.which is usually the banjo bolt at the master cylinder end.
    If you bleed the brakes from the caliper, the air has to travel all the way down against gravity to be expelled.
    We get around this on our race bikes, by fitting a banjo bolt with a bleed nipple screwed in the end. This allows us to bleed that last bit of air out in the morning and get perfect brakes every time.

    Also, when you bind the brakes you do not need a lot of pressure or need to leave it over night. 1 hour will usually do.
  5. He is riding a triumph! :p
  6. Bikes are relatively simple to bleed, you can get to everything easily.
    I start at the top and work down, cracking every banjo fitting etc and bleeding each connection. Bikes with distribution blocks on teh front forks can be a problem, air can get trapped in the block.
    I had all sorts of issues trying to get a nice lever on the Z, I ended up unbolting the caliper and distribution block and hanging them from a wire so the air would run up to the caliper from the distribution block.
    I don't think tying the lever off overnight works very well ( I tried it several times), if you look at a bike master cyl, any air can rise up by itself and be expelled through the compensating port. I have seen compensating ports blocked though, so make sure they are clear.
    All pressurising the fluid does is make the air bubbles smaller and more numerous.
    I used to have a neat little one way valve that had a piece of clear hose on it, but now I just use clear PVC tube and a glass jar to bleed in.

    Regards, Andrew.
  7. I bought an automatic brake bleeding kit on e-bay for $5.
    it arrived yesterday, will let you know how it works on the weekend!
  8. I don't agree. I have seen pressure applied to a system with a clear hose and seen the small air bubbles join together to form larger ones as they rise to the top.

    Another trick is to tap the sides of the hose with a spanner to help shake off the little bubbles which cling to the sides and help them on their way up.
  9. Jaqhama said it all. The other thing is to avoid getting air in in the first place. If you put a little pressure on the lever before cracking (not wide open) and shut it as the lever hits the bottom of its stroke you shouldnt get air back in.
    As for grease (does any one still do this?) you must use something compatible with brake fluid or you will risk contaminating (and reducing the boiling point) of the fluid . Brake assembly grease (sometime called rubber grease) is basically it - however thats a problem looking like a solution.

    Above all if you arent confident, mechanically inclined etc leave it for the professionals. You may only get one shot at getting it right.
  10. Probably one of the most painless ways to bleed your brakes is to find a nice big syringe & some plastic tubing that fits over the bleed nipple. Pop the top off your master cylinder, fill the syringe with clean brake fluid, slip the tube over the bleed nipple, crack the nipple & squeeze. As the air wants to naturally rise to the top you will find this way will help get rid of any air. Just keep your eye on the master cylinder resivour so you don't overflow it.
    Before you start bleeding this way, you might want to pump a bit of fluid through the system the normal way, in case there is any crud in the calipers that wants to find its way up to the master cylinder.
  12. No particular order. I actually found the GTR a lot easier to bleed than teh Z for some reason, even with dual calipers.
    If you like two finger braking, don't ever ride an old Z! Four fingers, and you will NEVER lock the front.

    Regards, Andrew.
  13. Unless bleeding ABS or linked brakes (eg VFR800) there is no particular order. It can be easier with two people working in sync (necessity on cars and even my then 9 year old son helped).
    Make sure there is firm pressure on the lever/pedal before you open (slowly) the nipple and close it before the lever hits the bottom of its stroke. Firm pressure will give sufficient fluid velocity to push air against gravity effectively and keep repeating consistantly until no air comes out.

    If replacing fluid use a syringe to remove the excess from the resevior rather than pumping it through (less opening of the nipple reduces the likelyhood of air back flowing).

    Dont ever expose the fluid supply hole in the bottom of the resevoir or air will get in. TAny remaining old fluid will be flushed through in the bleeding process. Once air gets in it can be a biatch to get out and patience is the key.