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Front BB5 ~ no power.

ValyValy Posts: 1,321
edited April 2010 in MTB workshop & tech
The power has decreased pretty significantly - I thought it could be the pads or soemthing. So I tool them out had a look, wiped with toilet paper - seemed to be okay. I took out some older pads and put them in - they were not completely worn out. Just about nothing happened when I pressed the lever - the moving pad did move in and did contact the non-moving one. But nothing. I put the first the cleaned set of pads in and same - just about nothing happens.

When I press the lever about 4/6 of the way it seems a bit stiffer than normal and on a ride yesterday it had a little "knot" in it whe ni pressed it about 2/6 of the way (kind of before the braking would normally start). This "knot" did go away though, but the lever felt the same as above.


THis is a front BB5 brake with the G2 rotor - it is reasonably clean, similar to the rear one really.


Any ideas what this might be? I booked the bike into a shop to get it looked at, but that will be on Friday... so I would not mind sorting this out sooner if I can. :P

Thanks.

Posts

  • supersonicsupersonic Posts: 82,708 Lives Here
    Sounds like could be contaminated.

    Clean the rotor with meths, and fit new pads. Bed in.

    make sure cable is clean.
  • xtreemxtreem Posts: 2,965
    Make sure the right pad is as close to the rotor without rubbing on it.
    If you did that, most likely it's contaminated.
  • ValyValy Posts: 1,321
    I changed the one of the pads - so now there are two different ones (the Avid one and one from NCx or soemthing similar) as they combine to have the most "stuff" left. I wiped the disk and there was more or less no improvement.

    I'm thinking it might be that the moving part is pushing in, but does not exert any noticable force. If so, the brakes are most liekly broken. Somehow. :?
  • CFSCFS Posts: 124
    Have you adjusted the fixed pad position as suggested above? On shimano cable disks this can make a big difference. They use an allen key not sure about your brakes.

    You also may need to adjust the moving pad with the barrel adjuster at the lever.
    Shot by both sides...
  • ValyValy Posts: 1,321
    CFS wrote:
    Have you adjusted the fixed pad position as suggested above? On shimano cable disks this can make a big difference. They use an allen key not sure about your brakes.

    You also may need to adjust the moving pad with the barrel adjuster at the lever.

    Yeah - done both. The non-moving pad is as farout as it will go. It is worn, but still about 1mm left.
  • Deputy DawgDeputy Dawg Posts: 428
    Follow Super's advice. Mismatched pads are just asking for problems as they'll both want to brake at different rates.
    Statistically, Six Out Of Seven Dwarves Aren't Happy
  • xtreemxtreem Posts: 2,965
    The non-moving pad is as farout as it will go
    How do you mean, farout.
    When it's worn the pad sometimes can't touch the rotor when it's turned all the way
    as close to reach the rotor, but still doesn't reaches. Put fatter pad or realign the caliper.

    Also make sure the pads are worn equally on their surface, not at an angle which
    causes only small amount of braking surface on the pad to touch the rotor.

    Still, new pads and clean rotor is the best choice I think.

    Btw, you'll never manage to worn the pads completely on the BB5.
    Unless you use some thin spacers behind the pads.
  • ValyValy Posts: 1,321
    Xtreem wrote:
    The non-moving pad is as farout as it will go
    How do you mean, farout.
    When it's worn the pad sometimes can't touch the rotor when it's turned all the way
    as close to reach the rotor, but still doesn't reaches. Put fatter pad or realign the caliper.

    Also make sure the pads are worn equally on their surface, not at an angle which
    causes only small amount of braking surface on the pad to touch the rotor.

    Still, new pads and clean rotor is the best choice I think.

    Btw, you'll never manage to worn the pads completely on the BB5.
    Unless you use some thin spacers behind the pads.

    Yeah - at the front at least. I've worn the rear pads to about... I dono - 1/10th or 2/10th of a mm before. The front does not seem to be so though.

    Yeha - I might just have to get a set of new pads.
    _____________________________________________

    DD - I was just trying stuff out as the drop off in power was pretty sudden.
  • ValyValy Posts: 1,321
    UPDATE:

    Fitted new pads and all is well again. I guess I did not want to put it down to that as

    a) it's £15 for new pads
    b) I thought there might be a bit of power in them if the pads wore out, but there was almost literally, nothing.

    Thanks for the replies. :D
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