Bleeding/pressurising front Brake

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  • kingchops
    kingchops
    16 years ago

    I just swapped over my front brake line from the stock line to a HD braided line.  I've bled all the air out of the new line and the brake seems to work ok.  But I can't seem to get as much pressure in the lever as before.  That is, I need to pull the lever in a fair bit to get the brake to engage.  This is the method I've been using to pressurise the brake:

    1) Connect plastic hose and container to front bleeder valve

    2) Pull and hold lever in about quarter travel, then open bleeder value

    3) Pull and hold lever in another two quarters travel, fluid bleeds through hose, close bleeder valve

    4) Allow lever to return fully out with bleeder closed

    I tried this method for about 5 minutes and like I said I've managed to pressurise the brake somewhat.  Should I continue this method longer as it seems to be working or does anyone have a more effective method or pressurising the fron brake?

  • Rocket
    Rocket
    16 years ago
    You could also try cracking the banjo bolts(particularly on the M/C) a little when you pressurise the system with the lever as there may be an air pocket there.
    Squeeze the lever and wrap some rag around the spanner and banjo bolt and just bleed some fluid out of the connection.
    If there's any loops in the hose where an air bubble can sit at the highest point, then this could be a problem.
    If you've got a twin disc front, crack the banjo bolts on the block under the steering head where the lines split into two as well.
    Failing all this, find a mate with a vacuum bleeder.

    Also, when I bleed a brake, I squeeze the lever and pressurise everything and then crack the nipple, then when the lever hits the handlebar, close the nipple. Release it and repeat.
    I don't hold the lever steady and crack the nipple before squeezing.
  • ANDYK
    ANDYK
    16 years ago

    Did this a couple of weeks ago KC put braided brake clutch and throttle cables on took a while to bleed brake but turned out ok this is what i did

    took top cover of and filled up with dot 5

    put some brake fluid in a glass ,got a tube one end in glass the other on bleed nipple ,make sure glass and tube is sitting higher than caliper

    make sure nipple is done up and pump that lever until you feel some resistance ,keep pressure on the  lever and while your doing that just open the nipple as you open the nipple the lever will go all the way in ,dont let it out until you have closed the nipple again

    then pump again and repeat  ,everytime you do it the lever will move in less to feel resistance

    Worked for me 

    I also had the problem once doing the brakes on the car when i didnt get anywhere and i did what scotty has said and it solved the problem

  • kingchops
    kingchops
    16 years ago
    Yes, good point Scotty I'm definately using DOT 4 which is specified on the lid of my m/c.
  • Mainey88
    Mainey88
    16 years ago

    DOT 5 Brake fluid is fully synthetic and should not to be used as it can stuff your seals but you can use DOT 5.1 and as scotty said dont mix blends.

  • kingchops
    kingchops
    16 years ago
    Just an update on this, I managed to do another session of bleeding and I've got the lever a lot firmer now, can't really tell if it's as good as before but good enough to test ride. I might give it a good blat to loosen up any more air that might be in there and give it another bleed. Thanks all, for your help.
  • Rocket
    Rocket
    16 years ago
    Umm here's a dumb question for you KC.
    When you did all this, did you happen to remove the caliper and push the pads open ? Maybe changed pads ?
    If so, have you pumped the pistons back out so the pads are touching the disc/s? You'll never get lever pressure if the pistons arent pushing against anything.

    Have you missed a bleed nipple on the caliper ?
    I don't know how many they have on sporty calipers but if there's two, you need to bleed both.


    If none of these work, give up a buy a Virago.
  • way out bush
    way out bush
    16 years ago

    Pretty close to what kiwidave said but i was shown years ago by a bloke-  Go to local vets and but biggest syringe they have and some clear hose.  Put on nipple at bottom and push fluid up to the resivoir.  Have not done it for years but i have done it and it works.

  • Chip_3
    Chip_3
    16 years ago

    Hi gmeikle,

    Your the only one with the correct way of bleeding brakes, the only thing I do different is by putting spacers between the disk and shoes to force the pistons in as far as possible then I pump the brakes and put a cable tie on the forced handle over night, just as you do with elastic bands.

    by the way I am nearly 65 so you gat a few years to catch up with me.

    good one mate, show the littlie boys how its done with no shit \errr bullshit.

     

  • Fr3d
    Fr3d
    16 years ago
    Want a rock hard pressure? After many years of working on my own brakes I came up with this; it works every time. I can do it by myself and its real quick.

    Go to the chemist and buy a 60ml syringe body, maybe $10. Then buy a metre of clear tube that will fit on the end of the syringe and bleed nipple. I also bought a section of oversized clear tube, about 300mm long that fitted over other clear tube and the bleed nipple to get a perfect fit. The seal with one tube over the other was no problem.

    Fill the syringe with your type of brake fluid, connect it to the pre connected tube on the nipple and pump the fluid throught the nipple and back into the master cyliner. Twin disc, single disc, does not matter - this will remove any air out of the line/lines. Carefull not to blow back fluid too fast. Dont want fluid all over your ride by overfilling or presurized spray going everywhere. When the master cylinder is filled lock off the bleed nipple and do the other side if you have twin discs. After this is completed, bleed the brakes like normal and you will find very little air. I have found a couple of bleed cycles is more than enough. This method will fill/bleed an emply master cylinder and lines in two minutes. I have not tried it with reconditioned empty calipers but cant imagine any issues.

    I have tried alot of beeding devices and spent hours trying to get full pedals with my other half bitching all the way. This works!

    Fr3d

  • Fr3d
    Fr3d
    16 years ago
    I use a 60ml syringe body with a clear plastic tube and pump brake fluid up into an empty master cylinder from the caliper nipple. Works every time and I can get a rock hard brake pedal in 5 minutes. I have got twin discs now and I just locked off one and pumped the other side and locked off. Made sure the master cylinder was not over full and did not pump hard enough to spray fluid around. Once the lines are primed on each side, give a quick couple of bleeds on each side and presto. You wont get a better way and you can do it by yourself.

    Fr3d
  • AJ56
    AJ56
    15 years ago
    Replaced the fluid in my front Thursday afternoon and got some air in the line, I have a one man brake bleed attachment but it sucked some air in to the caliper when using it. So went to the old method and am still having problems so came here and read this thread. OK Tried all of these methods and still have spongy front brake lever. I ran the bike today and the front lever is not as firm as it was. Any ideas, I will be replacing my front lines soon and will probably do the pads at the same time and don't want to have the same problems that I am having this time.

    AJ
  • AJ56
    AJ56
    15 years ago
    Had another go today, and bingo more air came out. It is what is was prior to changing anything. What a pain in the arse these are. I have done a lot of cars and never had a problem like this.
  • ratz
    ratz
    15 years ago

    Just did a service on M/C an Caliper to remove a few years of snot from the Sporty brake system, after the clean, the hone and inspection/rebuild i ended up with the dreaded bleed, followed the wkshop rules from manual and basically u can stick it up yor blurta, got the 60ml syringe pumped it up from the bottom and 5mins later nice bled firm brakes minimum fuss, gotta luv that, cheers from that fuckin Rat NO FLAMERS

  • Peter
    Peter
    15 years ago
    Will it only work with the HD BIG FLOGGER or is there an aftermarket tool I can purchase, always looking to save a penny.
  • Ozbiker69
    Ozbiker69
    15 years ago
    Sometimes you just have to keep work on the bleeding process before it comes u[ trumps. I did mine a few months back when i replace the front line. It bleed up perfect first go. I also have a bleeder here that works on the compressor. They cost a few dollars, but do work well.
  • DNO
    DNO
    15 years ago
    Try leaving the brake system under pressure over night. This helps to force any air to the surface. Simply cable tie the lever to the bars and leave over night. Works 99% of the time.
  • steveoc
    steveoc
    14 years ago
    Spot on , the backbleed is 100% the way to go .
  • hot dog
    hot dog
    14 years ago
    i had the same prob once front break would not come up . if you cannot bleed it in 5 mins then your master cylinder needs kitting out . also make sure you are using the write break flued .5
  • DASH71
    DASH71
    14 years ago

    Thanks for the tips guys. Just fitted up my apes over the weekend and for the brake line I used the reverse bleed with the small oil can method. It worked well. I slowly worked the fluid up into M/C locked of the bleed nipple, then a minute or so on the lever and repeat (Keep going until there are no more tiny bubbles coming up through the M/C). I did this couple of times and the lever was about 3/4's there. Pulled the lever in and taped it off and by the morning it was rock solid.

    Thanks again for the tips.

    Oh, and I picked up my extened brake line from local brake joint for $75 Just took in my old line, told them the length I needed and colour and 1hr later job done.   

    DASH

     

     

        

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