Disc Brake Squeal and Vibration STILL!

richf
richf Posts: 104
edited September 2010 in MTB workshop & tech
Just had my brakes serviced and bled, Now my rear brakes squeals like nothing I have ever heard and there is serious vibration through the frame, The guy in the shop told me to bed them in for 10 miles so i did 20-30 miles easy riding and braking.

Yesterday I went out for a downhill ride and had to stop because it was getting embarrassing braking with the noises they were making! Anyone got any tips on how to stop this or whats causing it?

I have been back to the shop and they suggested roughing up the pads again then trying to re bed? or book it back in with them next week.

Cheers
Rich

Comments

  • supersonic
    supersonic Posts: 82,708
    Bedding in takes a few good hard stops, or they glaze over and can squeal.

    Sand the pads, and clean the rotor and start again. Also check all the bolts are nice and tight.
    GT ZASKAR CARBON TEAM

    VOODOO CANZO

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  • richf
    richf Posts: 104
    OK I was told to lightly brake to bed them in! I'll clean them all up and try doing some hard braking see if that works! Have also heard about putting copper slip on the back of the pads?

    Cheers
    Rich
  • supersonic
    supersonic Posts: 82,708
    Only a dab of copaslip, and only if there are no holes in the backing.
    GT ZASKAR CARBON TEAM

    VOODOO CANZO

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  • richf
    richf Posts: 104
    There are holes on the back so won't do that then!
  • supersonic
    supersonic Posts: 82,708
    Really get some good hard stops in. Say 20 in a row - then squirt plain water on the pads/caliper. It can help them bed.
    GT ZASKAR CARBON TEAM

    VOODOO CANZO

    Come and see me at https://www.facebook.com/biketyke/
  • richf
    richf Posts: 104
    There are holes on the back so won't do that then!
  • richf
    richf Posts: 104
    Right been out and sanded pads cleaned rotors then went cycling around 15mph and braking hard as you suggested around 20 times then as I headed back towards the house I progressively broke and the squealing and vibration is still there. It only does it when progressively braking?

    This is really annoying me now please help!!
  • nicklouse
    nicklouse Posts: 50,675
    the brakes are?

    and what did you use to clean them with?
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
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  • richf
    richf Posts: 104
    I assume its the brakes but the vibration goes through the frame, I used muc off disc cleaner to clean the discs and sanded the pads.
  • catkinso
    catkinso Posts: 2
    I have a similar problem.

    Have changed rotors, pads, and even callipers.

    Just switched over to another dear wheel, and hey presto vibration has gone.

    Seems like something in the rear hub is resonating and causing the vibration.

    Going to the shop tomorrow to see if this is cause.

    Interestingly the looser I have the QR the better the vibration gets.

    hope this helps!
  • Chaz.Harding
    Chaz.Harding Posts: 3,144
    If you have tried re-aligning the caliper SEVERAL times, as some can be a bit of a bugger to get right, and bedded them in properly. As 'Sonic said, take a camelback, and some water, get the brakes as hot as you can, braking hard and sharp (not dragging the brakes) and squirt them.

    Before you try to bed them in, sand the pads down. Take the rotor off, and clean it in IPA or similar substitute. Then sand it down, moving outwards from the centre, so the scratches go at 90° to the scratches caused by the pads.

    IF you do all of this, and it STILL squeals, then go to your LBS, and get them to re-face the disc mount, and repeat the whole process again. Is a pain, but brakes are important!
    Boo-yah mofo
    Sick to the power of rad
    Fix it 'till it's broke
  • catkinso
    catkinso Posts: 2
    well thats a great solution for brake screech, but not the vibration were talking about?

    Bear in mind that change of callipers, pads, and rotors has not helped here.

    I have done some further tinkering though and fixed this issue for myself.

    Found that (in my case) the rear hub was slightly loose. Have tightened this up finger tight (I don't have a cone tool) and the vibration has all but gone.

    Will get to the shop tomorrow to get the hub properly tightened but this has been a long standing issue for me and is now resolved.

    This was very different from noisy brakes as the vibration was so bad it actually prevented me from feeling the bikes movement throught the bars/pedals etc.

    I also found reference on the Magura site to this vibration issue, and they rec'd looking at the hub as an issue.

    All fixed.

    Thanks for input though, often helps to get other idea's.
  • squealout
    squealout Posts: 1
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