CityCyclingEdinburgh Forum » Questions/Support/Help

Disc brakes - spongy & noisy

(8 posts)
  • Started 8 years ago by Schemieradge
  • Latest reply from ivangrozni
  • This topic is not resolved

No tags yet.


  1. Schemieradge
    Member

    Can anyone suggest the most likely cause of this?

    Shimano M595 disc brake has been working great for 2.5 years. Replaced the pads about 6 months ago because I thought their stoppiness might be easing off a bit - not big deal though.
    But in the last month or 2 the brake lever has started to get quite spongy, I have to pull quite hard to get any stopping power at all, the brake lever creaks.
    If I'm coming to a stop coming down a hill or something where I have to brake for an extended period, once I've been braking for about 10 seconds or so, the brakes start squealing like mad.. annoying, but once they start squealing they work much better. They've always squealed in the wet - but never on dry days.

    Does this sound like the rotor and pads just need a good clean?
    Or am I into bleeding territory?

    Posted 8 years ago #

  2. I were right about that saddle
    Member

    Spongy brakes need bled. DOT4 or mineral oil?

    Posted 8 years ago #

  3. Schemieradge
    Member

    Mineral oil apparently.

    Posted 8 years ago #

  4. Cyclops
    Member

    The sponginess is due to air in the system so the brakes need bled. The squealing might be fixed by cleaning but unfortunately some discs/pads are noisy whatever you do with them.

    Posted 8 years ago #

  5. acsimpson
    Member

    Bedding new pads in correctly can also help with squealing. Braking sharply from over 15mph to stationary 20 times is a good place to start.

    Posted 8 years ago #

  6. I were right about that saddle
    Member

    @schemieradge

    I have a Shimano oil bleeding kit. Happy to show you how to use it if you can wait a couple of weeks. Very easy.

    Posted 8 years ago #

  7. neddie
    Member

    The squealing can be caused by a build up of a smooth glassy-like substance on the pad (possibly due to the surface melting slightly under braking).

    As acsimpson said, doing some heavy braking should help remove the glassiness.

    Obvs, you'll need to bleed 1st, before you can do the heavy braking thing.

    Posted 8 years ago #

  8. ivangrozni
    Member

    A good way of getting rid of the squealing too is to apply the brakes so that you can still pedal albeit requiring considerably more force. Pedal against the brakes through several wheel revolutions (20m or so) and the squeal will be reduced or gone. Essentially this is doing the same as what acsimpson suggested. Applying grease (copper grease?) to the back of the pads can also help to dampen the vibration causing the squeal.

    The sponginess is a sign that the brakes need to be bled (as all have noted) but the sponginess can also be advantageous - My brakes have gone a little spongy recently too but I find that I am enjoying a bit more modulation with my braking.

    Posted 8 years ago #

RSS feed for this topic

Reply

You must log in to post.


Video embedded using Easy Video Embed plugin