1. After 20+ years it's time to pass the torch. If you are interested in acquiring this forum please contact support@cv-performance.com for details. Any spam will be reported and blocked.
  2. Welcome to Bike Talk, a forum for all bikers and motorcycle enthusiasts. If you are new to Bike Talk, be sure to register for free and join the conversation.

    There's always someone around willing to help out with questions or give a friendly wave back. All Harley and metric riders are welcome.
Bike Talk Motorcycle Forum is For Sale Welcome to Bike Talk

Broke Brakes

Discussion in 'Motorcycle Tech Talk' started by birch, Jul 20, 2009.

  1. birch

    birch New Member

    Joined:
    Sep 24, 2007
    Messages:
    18
    Likes Received:
    0
    Location:
    Kirby, Ohio
    2001 Roadking
    Front rotors were warped so I replaced them. After replacing, the front brakes needed pumped to get good "pedal".
    I bled them conventionally and by pumping fluid from the caliper up. no difference.
    I rebuilt master cylinder, no difference.
    I rebuilt both calipers, no difference.
    I replaced the brake lines, you guessed it, no difference.
    With brand new pads it will work just okay.
    There are over 100k miles on everything but the rotors and brake lines.

    Any ideas?
    birch, Jul 20, 2009
    #1
  3. hotroadking

    hotroadking Super Moderator Staff Member

    Joined:
    Jun 16, 2004
    Messages:
    13,682
    Likes Received:
    584
    Location:
    Mouseville USA
    when you say "no difference" do you mean you can't get pressure?

    Dual fronts can be a PIA, I've seen them have no pressure, sit overnight and bam pressure...

    I have two ways I do this.

    1) Get a brake bleeding kit from a parts store, it's a reverse unit, you fill the MC, top off, pull in handle (string, rubber band, wife, girlfirend (although not wise to have both around bike at same time) freind etc) open

    Connect the bleeder to the valve on the caliper, open and start pumping the unit, it will draw the fluid though the caliper and down from the mc. Have whoever is up by the mc refill Stop when you get constant fluid (no bubbles) Do the same for the other.

    Then, fill MC, put cover on, and pump, should work, takes time,

    2) I have a big horse syringe from a tack store, with some tubing, I have the brake handle held back, then attach to the Caliper and force fluid in from the bleeder valve to back fill, this can force bubbles out of the caliper.

    Tapping the brake line from bottom to top helps, you have that T and sometimes a bubble will get trapped.
    hotroadking, Jul 20, 2009
    #2
  4. birch

    birch New Member

    Joined:
    Sep 24, 2007
    Messages:
    18
    Likes Received:
    0
    Location:
    Kirby, Ohio
    I appreciate the information.
    I did fill a squeeze bottle and connect it to the bleeder and pushed fluid up and into the master cylinder until it had no bubbles.
    Do you think the vibration is letting the pistons relax back in the calliper too far?
    When the bike isn't running and it is on the kickstand the brakes are firm, it is when I fire it up they get spongy.
    birch, Jul 20, 2009
    #3
  5. hotroadking

    hotroadking Super Moderator Staff Member

    Joined:
    Jun 16, 2004
    Messages:
    13,682
    Likes Received:
    584
    Location:
    Mouseville USA
    typically when the rotors are warped or if the caliper is not aligned correctly you can get heat transfer that boils the fluid and then-- no brakes...

    I'd put it up on a stand, and freewheel the front tire checking the rotors in the caliper.
    hotroadking, Jul 20, 2009
    #4
  6. birch

    birch New Member

    Joined:
    Sep 24, 2007
    Messages:
    18
    Likes Received:
    0
    Location:
    Kirby, Ohio
    Yea, I double checked the rotors when I rebuilt the calipers.
    all the brake fluid was changed when I replaced the brake lines.
    I have been dicking with this for 8 months now. Noone will believe it till they witness it.
    birch, Jul 20, 2009
    #5
  7. hotroadking

    hotroadking Super Moderator Staff Member

    Joined:
    Jun 16, 2004
    Messages:
    13,682
    Likes Received:
    584
    Location:
    Mouseville USA
    when the bike is on the lift
    and you rotate the front wheel,
    no side to side?
    hotroadking, Jul 20, 2009
    #6
  8. birch

    birch New Member

    Joined:
    Sep 24, 2007
    Messages:
    18
    Likes Received:
    0
    Location:
    Kirby, Ohio
    no, i put new bearings in it last year.
    it doesn't need to go down the hyway to loose pedal, i can go out and i got pedal, i fire it up and take it off the kickstand and the pedal almost goes away.
    birch, Jul 20, 2009
    #7
  9. hotroadking

    hotroadking Super Moderator Staff Member

    Joined:
    Jun 16, 2004
    Messages:
    13,682
    Likes Received:
    584
    Location:
    Mouseville USA
    you have air still in the system...

    either it's getting in from the rebuild somewhere,
    or you're not getting it all out.

    Turn the bars to the left.
    take the top off, use a vacuum operated bleeder,
    be sure all the air is out

    Tap on the lines with a screwdriver from bottom to top

    with the cover off, lightly tap the end of the brake lever
    you'll see bubbles come out, when they are all out the fluid will jump vs
    bubbles coming. up.
    hotroadking, Jul 20, 2009
    #8

Share This Page

XenPorta © Jason Axelrod from 8WAYRUN.COM