disc brake rubbing

timoneill84
timoneill84 Posts: 5
edited June 2018 in MTB workshop & tech
Hi all

So i've recently got myself a second hand Norco Fluid 7.3, 2017 model. The front hydraulic brake is rubbing slightly. I've tried taking the pads out, as far as I can see they look fine. I've unscrewed the callipers, held the brake lever and tightened again (as per a youtube vid I saw) and taken the wheel off and put it back on but the problem is still happening. I don't think the disc is warped.

Anyone got any ideas as to what it could be? I was thinking of buying new pads first and if they don't work then getting a new disc. It's very hard to see what part of the pad if rubbing, if this is causing the issue!

Thanks

Comments

  • kajjal
    kajjal Posts: 3,380
    If the disc is warped too much spinning the wheel will show this.

    Is the pad clearance less at the front than the back wheel of the bike ?

    If it is remove front wheel, carefully & gently press the pads back with a screw driver. Then put wheel back in and get bike up to speed and brake a few times.

    If this doesn’t work look down the pads with the front wheel in, if one side is closer to the rotor or moves more slowly you may need to adjust the caliper by eye rather than the squeeze the brakes on method.

    Failing that there may be too much brake fluid in making the pads too close. Unscrew the bleed port on lever , carefully & slowly push pads back, while holding pads back screw the bleed port screw back in. This can be a little messy and is easier as a two man job.
  • t0ffeeman
    t0ffeeman Posts: 47
    If the front & rear rotors are the same size, try swapping them over, see if the problem swaps then you'll know if the rotor is warped or not.
  • timoneill84
    timoneill84 Posts: 5
    Hi both

    Thanks for your replies & sorry for the delay.

    Just tried to fix again and getting nowhere. I can see a gap on one side of the rotor but not on the other. Also one pad will move in with a flat head screwdriver pushed against it whilst the other won’t (same side there is no gap). It does move when applying the brakes though. To make matters worse I took off the bleed port screw next to the pads, pressed the leaver, some oil came out and now there is too much travel. There are gaps either side with the wheel bolt loose but one side disappears as I tighten the wheel back on. It’s almost like my suspension isn’t parallel.

    Don’t really want to swap the rotors as i’m sure I won’t be able to hear any rubbing at the rear due to the free hub noise.

    Any help appreciated.

    Tim
  • 02gf74
    02gf74 Posts: 1,168
    Sounds like one pad is seized.
  • timoneill84
    timoneill84 Posts: 5
    Yeah think so. I’ve just realised one of the pistons behind the pads was seized. I pushed it back in but every time I pressed the leaver it would come out and not go back in. I’ve added more mineral oil to the system now and the brake doesn’t work at all now grrr. Will a brake bleed fix this? Thanks
  • supersonic
    supersonic Posts: 82,708
    Keep working the pistons out, and pushing back in, whilst cleaning any dirt away and lubing them with whatever fluid your brakes use. Never let them push too far out though, we are only talking a little bit here, 2-3mm.

    Then push them all the way home, fit a bleed block and bleed them.
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  • timoneill84
    timoneill84 Posts: 5
    Thanks will give that a go. They were quite far out already so hope that hasn’t done anything too bad.

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