Tw*t-proof guide to brake bleeding?

Discussion in 'UK Motorcycles' started by Dave Jennings, May 16, 2005.

  1. As header. 1400 failed it's MoT today as both sets of brakes were very
    spongy, with too much travel. Pads are fine so almost certainly air in
    the system, I are told. ( He was fine with the exhausts,which was a
    result ) .

    So, I did a quick google to see what UKRM had previously said on this,
    and got this from TOG in Feb 03:

    To bleed the brakes: attach piece of bleed pipe to bleed nipple. Put
    other end of pipe in glass jar.

    Pump lever half a dozen times, and then pull in. Without releasing
    lever, open bleed nipple.

    Close nipple. Release lever. Pull in lever. Open bleed nipple. Close
    nipple. Release lever. Pull in lever.

    And so on and so on, remembering to top of the fluid reservois as you
    go. When no bubbles come out of the pipe and the lever feels firm, it's

    Now, that seems easy enough. Just a quick question - before I do this,
    do I remove the appropriate cylinder cover for the brake I'm working on?

    Also, is the pipe/jar interface just to stop brake fluid hitting the

    Finally, is this the 15 minute job it suggests or could I be there for
    hours deopending on amount of air in system?

    If it helps, when I press the rear pedal as is I hear a slight knocking
    sound - would that be the pistons trying to move out?

    Ta in advance, as always.
    Dave Jennings, May 16, 2005
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  2. Dave Jennings wrote
    How long is a piece of string?

    I feel it really is a two handed job, unless you are either proficient
    or have Gadgets.

    Even then, for some completely unknown reason, bike brake system /can/
    be a right bastard to bleed, sometimes, on some bikes, but not always.
    It is a mystery.
    steve auvache, May 16, 2005
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  3. Dave Jennings

    Monkey Guest

    If there's no valve on the tubing you're using, you'll need jar partially
    filled with brake fluid (to stop air being sucked back up into the system).
    No - only the reservoir cap and bleed nipples are opened during the process.
    Where else is the fluid going to go? Plus see above
    It's much quicker and easier if you have someone to help you (pumping /
    holding the level while you do the bleed nipple, and make sure all the
    tubing stays connected (it has a nasty habit of popping off the nipple when
    under pressure). Even so, allow at least a hour if you've never done it

    Some other important tips:
    - Don't forget to leave the jar of fluid to settle for 24 hours beforehand,
    or you'll be putting aerated flud into your system
    - DO cover all paintwork around the area - you _will_ spill some brake fluid
    - Dispose of any leftover fluid from the new jar after you've finished both
    brakes - it doesn't keep.
    Monkey, May 16, 2005
  4. Dave Jennings

    Martin Guest

    Dave Jennings wrote:
    Yes, otherwise you won't be able to top up the brake fluid. If the
    fluid is dark brown it is worth flushing a fair amount of fresh fluid
    through the system.
    It also stops it from pissing all over your garage floor.
    This appears to be your first time,I would put aside a couple of hours
    to make sure you do it right, do you want a hand?
    Might be, might not.

    "For a minute there, you bored me to death."
    VTR1000 Firestorm
    martin dot smith nine zero three at ntlworld dot com
    Martin, May 16, 2005
  5. Dave Jennings

    TMack Guest


    The problem with trying to make anything "twat-proof" is that twats are so
    damned ingenious........

    TMack, May 16, 2005
  6. Martin yik-yakked:
    Nice and clear, all replaced fairly recently, ta.
    Ta for the offer. Let me have a try first, and if I'm stuck, then
    expect a shout and some beer tokens!
    Ooh. Very coy!!
    Dave Jennings, May 16, 2005
  7. TMack yik-yakked:
    True. I get up early to connive devious ways of beating twat-proof
    Dave Jennings, May 16, 2005
  8. Monkey yik-yakked:

    Great advice there, ta!
    Dave Jennings, May 16, 2005
  9. If you close the bleed nipple before releasing the lever, then air can't
    get sucked in....
    That it does.

    What he said.
    The Older Gentleman, May 16, 2005
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