Rear breaks make grinding noise

Forums Mountain Bike Forum Rear breaks make grinding noise

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    • #98610

      Bike’s only 5 rides old. They’re disc breaks. The rear break doesn’t "squeek", it makes more of a grinding or abrasive noise. Noticed the noise on end of ride 2, beginning of ride 3. I really didn’t get into much mud or anything on the first 2 rides. I did make one hard landing though. Any thoughts on this? Could it be something I can’t see inside the caliper?

      Sounds EXACTLY like this: http://www.youtube.com/watch?v=G66ECz4f … re=related

      Worried I f’d up my new rig somehow…

    • #98611

      It helps if you mention which brakes you have….more than likely the pads are contaminated with dirt….Remove the wheels, use sandpaper and lightly go over the rotor (both sides) to clean it up a touch…..Remove the pads from the caliper and with the sandpaper on a very flat surface, skim the pads a bit to remove any debris from them. Then remove any dust off the pad and re-install everything.. Make sure the caliper is in line as well.

      http://www.singletracks.com/blog/mtb-re … e-service/

    • #98612
      "element22" wrote

      It helps if you mention which brakes you have….more than likely the pads are contaminated with dirt….Remove the wheels, use sandpaper and lightly go over the rotor (both sides) to clean it up a touch…..Remove the pads from the caliper and with the sandpaper on a very flat surface, skim the pads a bit to remove any debris from them. Then remove any dust off the pad and re-install everything.. Make sure the caliper is in line as well.

      http://www.singletracks.com/blog/mtb-re … e-service/

      They’re Tektro Novelas. Thanks for the feedback! I’ll definitely try it out… it’s kind of embarassing haha. I’m sure you recommend really fine sandpaper for this task?

    • #98613

      Use 180-240 is good enough….180 for the disks and 200-240 for the pads

    • #98614

      I realize I’m late to the game here, kyroush, but I was just in the same position as you last week. I’m Kind-of a noob, and just got a new ride earlier this summer. After about 75-100 miles I noticed my rear brake kind of -grinding- on the disc (They’re Promax Orange Mech Disc). I dropped by the LBS to have an adjustment done, and he seemed to fix the issue….while the bike was on the rack. Once I got it out again, and put my weight on it, it was still grinding. Fearing that I’d have to turn over the bike to the LBS for a week and miss out on a couple rides in the process, I took matters into my own hands and removed the rear caliper, discs, etc. What seemed to be happening in my situation is that the outside piston behind the pad was "stuck" just a little bit further than flush. Once I popped out the pad, popped the piston back into place, and worked in and out a little bit, I reassembled the whole thing, and it seemed to take care of the problem. The whole process probably took about 20-30 minutes, max.

    • #98615
      "kyroush" wrote

      [quote="element22":3o7xlirz]It helps if you mention which brakes you have….more than likely the pads are contaminated with dirt….Remove the wheels, use sandpaper and lightly go over the rotor (both sides) to clean it up a touch…..Remove the pads from the caliper and with the sandpaper on a very flat surface, skim the pads a bit to remove any debris from them. Then remove any dust off the pad and re-install everything.. Make sure the caliper is in line as well.

      http://www.singletracks.com/blog/mtb-re … e-service/

      They’re Tektro Novelas. Thanks for the feedback! I’ll definitely try it out… it’s kind of embarassing haha. I’m sure you recommend really fine sandpaper for this task?[/quote:3o7xlirz]

      i have the same pads and they squeal like a banshee. the manual said to spray them with brake cleaner, but , the can of brake cleaner says not to get on painted areas.so i’m not going that route.
      just looked around on you tube and found a vid that said to use rubbing alcohol. i’ll give that a try.

    • #98616

      The way I’d deal with it is to clean them out and break them in more. Some brakes takes a month to break in depending on how hard you ride.

    • #98617

      I would stay away from Automotive brake cleaners as they leave a residue and only flash off at much higher temps than what can be developed with bike disks….Using plain rubbing alcohol will not leave a residue. You could always use Methylhydrate as well for a cleaner degreaser.

    • #98618

      I stay away from anthing that starts with Meth. LOL 😄 Later,

    • #98619

      tried the alcohol and not much difference. although my brakes don’t squeal when wet.

    • #98620

      check to make sure the caliper is parallel with the rotor.

    • #98621

      my bb7’s give a little bit of squel, but nothing like my Juicy’s. The rear one on my 29er shakes the whole damn bike. I dont mind noise but the vibration is pretty annoying.

    • #98622

      Well check things like the quick release to make sure it is tight, as mentioned before, the brake caliper allignment, checking the pads for contamination, cleaning the rotor with some sand paper on a slight tangent, and pads, all can help.

      We have a brake guide here on singletracks and there is more detail there for you.

    • #98623

      Noise is dirt on the braking surface. The dirt can be pad material. The pads can be glazed which is from hard use and being dirty and also causes noise. Dirt= Grinding/ Glazing= Squealing. Break the glaze with sand paper and clean the crud off the surface. If the bike vibrates the rotor(disc) is not flat or is bent which helps the caliper get loose as well. Disc brakes are the bomb when they are set up correctly. However when they’re not it isn’t fun. Anyone want some nice V Brakes? Just asking. 😄 Later,

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