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Squealing Brakes

Bash82Bash82 Posts: 13
edited May 2018 in MTB workshop & tech
My Shimano Zee Hydraulic disc brakes are squealing quite badly. So far I have cleaned the disc with IPA, rubbed over the pad to get rid of the top layer incase it was contaminated and put some copper grease on the back of the pad. If there anything else I shoukd try before I buy new pads? It's both the front and rear.

Thanks

Posts

  • trekvettrekvet Posts: 220
    Did you bed the brakes in from new? Perhaps now is the time for some heavy stops from high speed? Find a downhill tarmac traffic free, and repeat stops to really heat the brakes up. PS. Do Not touch the disks. Good call on the copper grease, we used to use that on Ford Cortina pads in the '70s, as well as cutting a lateral grove across the centre of the pad to cure squealling, but you probably need to use them harder. Stay safe.
    The Wife complained for months about the empty pot of bike oil on the hall stand; so I replaced it with a full one.
  • cooldadcooldad Posts: 32,601
    edited May 2018
    Faffing generally doesn't help. Don't put any sort of grease, including copper grease anywhere near the brakes. Bikes are not cars and the brakes are far more sensitive.

    If you have sintered pads, which squeal replace with softer organic or kevlar pads.
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  • swod1swod1 Posts: 1,639
    Never put any grease near bicycle brakes no need for it.

    Pads must be bad if taken top layer off and still making noise.

    Is the brake caliper centered?

    The pads aren’t glazed are they this can be a cause of brakes making noise sometimes.
  • Bash82Bash82 Posts: 13
    Thanks for the advice, I thought I bedded them in but maybe I didn't do it enough? I'll try a few hard stops and see if that improves them at all before I try some new pads.
  • supafly1982supafly1982 Posts: 942
    Clean pads with ipa or brake cleaner. using fresh emery cloth or wet and dry Flat sand top surface of pads, clean again.
    Remove discs. Clean with ipa/brake cleaner. Use fresh emery or W&D paper using a flat sanding block and take any glazing off the rotor. I work small circles so there’s lines perpendicular to the rotation of the rotor. Clean again with cleaner.
    Centre your pistons and align Caliper.

    To bed in try pouring fresh, clean tap water over your Caliper so pads get wet. Go fast and stop hard. Do this a few times. Do not drag your brakes as you will polish/glaze the pads and rotors.

    Let us know how you get on.
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