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Bedding In Pads

richfrichf Posts: 104
edited July 2009 in MTB workshop & tech
I have been told various ways of doing this but I am still getting brake squeal and vibration through the frame.

I have just removed my pads and rotors and cleaned them with Muc off disk brake cleaner, I also sanded the pads as the looked glazed. I have let it all dry and re assembled making sure I didn't touch anything.

Now when I ride the bike shortly should I brake lightly and progressively or slam the brakes on a few times to get the pads bedded in a bit before I go down hilling tonight?!

Thanks
Rich

Posts

  • supersonicsupersonic Posts: 82,708 Lives Here
    Slam them on. Repeatedly.

    Some systems are very hard to stop squealing - a certain picth that the fork and frame can contribute to.
  • Soul BoySoul Boy Posts: 359
    Yup, I find a steepish hill, fast sprint, slam on the achors and at least 10 reps of this gets em bedded in. When I put new pads in my Avids you can feel them getting progressively stronger as you go.

    others will tell you not to bother, but if a jobs worth doing......

    Check all your bolts are tight, obvious I know, but sometimes that can cause a vibration
  • richfrichf Posts: 104
    Soul Boy wrote:
    Yup, I find a steepish hill, fast sprint, slam on the achors and at least 10 reps of this gets em bedded in. When I put new pads in my Avids you can feel them getting progressively stronger as you go.

    others will tell you not to bother, but if a jobs worth doing......

    Check all your bolts are tight, obvious I know, but sometimes that can cause a vibration

    Cheers Guys, Will do. and will double check my bolts just in case!
  • JAGGYJAGGY Posts: 167
    I usually wait till its wet and do a couple of downhill runs on my local trails. The grit and mud is quality for breaking them in.

    Cheers
  • joshtpjoshtp Posts: 4,329
    puting muc-off on them isnt such a good idea, brake cleaner or isopropyl is what you should use, muc-off probably wont damage them, but its not good for them either.
    I like bikes and stuff
  • -Liam--Liam- Posts: 1,831
    JAGGY wrote:
    I usually wait till its wet and do a couple of downhill runs on my local trails. The grit and mud is quality for breaking them in.

    Cheers

    Nah mate.

    Grit and wet will wear down unbedded in pads quicker than you can stop.
  • canada16canada16 Posts: 2,360
    puting muc-off on them isnt such a good idea, brake cleaner or isopropyl is what you should use, muc-off probably wont damage them, but its not good for them either.

    Are you serious? :lol: :roll:

    Go about 20 hit the brakes, do it again hit the brakes, that works for me.

    Hope used to supply a pot of mud to rub on your rotors, dont know if they still do.

    Now thats good customer serivce.
  • richfrichf Posts: 104
    puting muc-off on them isnt such a good idea, brake cleaner or isopropyl is what you should use, muc-off probably wont damage them, but its not good for them either.

    it was muc off disc brake cleaner I used, but was a waste of time! Been out tonight going down hill slamming brakes on, done this at least 20 times and no noise happy days! Then as I was slowing down on a big hill (not slamming brakes on but just slowing) the vibration and screaming came back. My mate that was a good 50 metres behind me asked me what the hell that noise was as he could hear it cleat that far away.

    What the hell am I doing wrong? The vibration is really horible and every bolt is done up really tight.

    Someone please help me!!!!

    Cheers
    Rich
  • You may find that your caliper needs aligning with the disk again, I always seem to have to adjust it two times with new pads (once when fitted and again after the first ride).
    This is why!
  • richfrichf Posts: 104
    You may find that your caliper needs aligning with the disk again, I always seem to have to adjust it two times with new pads (once when fitted and again after the first ride).

    Cheers I will give it ago!
  • joshtpjoshtp Posts: 4,329
    richf wrote:
    puting muc-off on them isnt such a good idea, brake cleaner or isopropyl is what you should use, muc-off probably wont damage them, but its not good for them either.

    it was muc off disc brake cleaner I used, but was a waste of time! Been out tonight going down hill slamming brakes on, done this at least 20 times and no noise happy days! Then as I was slowing down on a big hill (not slamming brakes on but just slowing) the vibration and screaming came back. My mate that was a good 50 metres behind me asked me what the hell that noise was as he could hear it cleat that far away.

    What the hell am I doing wrong? The vibration is really horible and every bolt is done up really tight.

    Someone please help me!!!!

    Cheers
    Rich
    thats fine, just the normal nanotech cleaner isnt such a good plan, the brake cleaner is good though
    I like bikes and stuff
  • .blitz.blitz Posts: 6,588
    Soul Boy wrote:
    Yup, I find a steepish hill, fast sprint, slam on the achors and at least 10 reps of this gets em bedded in.
    Providing you let them cool down inbetween stops :wink:

    Glazing the pads through overheating is just as bad as not bedding them in properly.
  • richfrichf Posts: 104
    Could the wrong rotor be causing this?
  • elPedro666elPedro666 Posts: 1,060
    Have you checked that the rotor isn't warped? Would make it juddery & (possibly) squealy...
    WTD:
    Green Halo TwinRail
    25.0mm-26.2mm seatpost shim
    Red X-Lite bling
    Specialized ladies BG saddle (white?) 155mm
    RH thumbie
    700x28c CX tyres&tubs
    Flatbars 620mm 25,4mm & swept, ti in an ideal world
  • richfrichf Posts: 104
    elPedro666 wrote:
    Have you checked that the rotor isn't warped? Would make it juddery & (possibly) squealy...

    The rotor didn't look warped, Just been and got a new one just in case thats the problem it's the last thing I can think of. Will check the rotor again when it comes off tonight!

    Cheers
  • elPedro666elPedro666 Posts: 1,060
    Regards bedding in, I was told NOT to slam the brakes on, but use them progressively, riding around dragging it gently.

    I know that's what you should do with cars/motorbikes so that they don't glaze, not sure it's the same theory.
    WTD:
    Green Halo TwinRail
    25.0mm-26.2mm seatpost shim
    Red X-Lite bling
    Specialized ladies BG saddle (white?) 155mm
    RH thumbie
    700x28c CX tyres&tubs
    Flatbars 620mm 25,4mm & swept, ti in an ideal world
  • A dragging brake will cause heat build up on a car or bike and glaze the pads up in the offending area.

    All pads should be glaze busted prior to fitting to remove manufacturing residue. Just go over the edges and face of the pads with 120 grit abrasive to take the shine off.
    This is why!
  • supersonicsupersonic Posts: 82,708 Lives Here
    elPedro666 wrote:
    Regards bedding in, I was told NOT to slam the brakes on, but use them progressively, riding around dragging it gently.

    I know that's what you should do with cars/motorbikes so that they don't glaze, not sure it's the same theory.

    Slightly different theory - do that with MTB pads and they have a habit of wearing through quick. The sudden heat seems to cure them.
  • elPedro666elPedro666 Posts: 1,060
    supersonic wrote:
    do that with MTB pads and they have a habit of wearing through quick.

    Ahh - that'll be why the shop recommended it...!
    WTD:
    Green Halo TwinRail
    25.0mm-26.2mm seatpost shim
    Red X-Lite bling
    Specialized ladies BG saddle (white?) 155mm
    RH thumbie
    700x28c CX tyres&tubs
    Flatbars 620mm 25,4mm & swept, ti in an ideal world
  • scazzerscazzer Posts: 254
    Hi all

    just thought i wud ask here rather than start new post :P ,ive just got new pads and i want to clean rotor before i put them on so just want to know if 'Surgical Spirit' is ok to use on them???
    cheers
  • In my frustrating experience with squeals I generally found it to be due the following -
    1- Caliper not centered.
    2 - Pad type and manufacturer : some are just worse than others. imo sintered are quieter when the track / weather is wet.
    3 - Something on the rotor (oil / dirt)
    4- Heat - some pads squeal when hot. Others when really cold.
    5- A small amount of copper grease on the back of the pad and on the retaining bold (if you have one) seems to help sometimes.
    Lastly an unusual problem I had with squealing brakes was due to one piston moving less than the other. This then tempoorarily bent the rotor as it went round. For some reason this uneven pressure & bending caused squeals and occasionally shuddering felt at the bars. To check for this look carefully at the pads (I presume they're centered properly) as you pull the lever. The pads should move in at the same pace and touch the rotor surface simultaenously. Even with a full pressure on the lever the rotor shouldnt move / bend. If not you can do a google on 'lazy piston' to find the fix.
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