Rear Disc brake squeal

Hi chaps got a giant fathom 1 2017 with shimano brakes got a bad squeal
If it were a car I’d take off disc clean and check surface then re face the pads if
Enough meat on them done this used a brake cleaner used on cars
Still have a tremendous squeal any thoughts would be gratfuiiy accepted

Thanks Tom b
Whoops who did that!

Comments

  • veronese68
    veronese68 Posts: 27,748
    Bike brakes don't like car brake cleaner as it leaves an oily residue. Clean the discs again using IPA, isopropyl alcohol not beer. But your pads are probably toast.
  • tomb57
    tomb57 Posts: 2,043
    edited April 2021
    Thanks Veronese I’m abut in the back of beyond where would I likely be
    Able to purchase some IPA from (I have some hobgoblin IPA in me
    Beer box but would rather drink it )
    Thanks for your help
    Tom b
    Whoops who did that!
  • veronese68
    veronese68 Posts: 27,748
    Enjoy the hobgoblin.
    The less entertaining IPA is also known as rubbing alcohol. I've got a feeling you might be able to buy it in a chemist's. I bought some in Maplin when they were still going. Some sort of electrical switch cleaner might do it. You need something that doesn't leave any residue at all.
  • lesfirth
    lesfirth Posts: 1,382
    tomb57 said:

    Hi chaps got a giant fathom 1 2017 with shimano brakes got a bad squeal
    If it were a car I’d take off disc clean and check surface then re face the pads if
    Enough meat on them done this used a brake cleaner used on cars
    Still have a tremendous squeal any thoughts would be gratfuiiy accepted

    Thanks Tom b

    Do the same as a car but rub disc surface with some wet or dry. Then plenty of hard braking to bed in the pads.
  • lesfirth
    lesfirth Posts: 1,382

    Bike brakes don't like car brake cleaner as it leaves an oily residue. Clean the discs again using IPA, isopropyl alcohol not beer. But your pads are probably toast.

    Let us all know what brand of brake cleaner you have been using. We can make sure we avoid it. I have not had that problem with any I have used.
  • tomb57
    tomb57 Posts: 2,043
    Thanks Les will let you know what brand later as I’m busy today
    Not able to get to shed
    Will try a near hardware shop for some
    IPA or similar
    Thanks all
    Tom b
    Whoops who did that!
  • JBA
    JBA Posts: 2,852
    Have you made sure the brake caliper is correctly aligned? If the pads aren't hitting the rotor squarely you can get horrible squealing.

    I bought a litre of IPA with spray nozzle from Amazon recently for less than a tenner.
    “Life has been unfaithful
    And it all promised so so much”

    Giant Trance 2 27.5 2016 ¦ Sonder Broken Road 2021¦ Giant Revolt Advanced 2 2019 ¦ Giant Toughtroad SLR 1 2019 ¦ Giant Anthem 3 2015 ¦ Specialized Myka Comp FSR 2009
  • tomb57
    tomb57 Posts: 2,043
    Got some wd40 electrical contact cleaner recleaned disc had some new
    Pads waiting so put those in Caliper looked ok and I know I haven’t
    Knocked it road tested quite as a church mouse
    Car brake cleaner was Holts which really surprised me as make is normally
    Good still I’ve learnt a lot now
    Many thanks to all for the help
    Tom b
    Whoops who did that!