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  1. #1
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    New XTR brakes howling during bed-in

    Just mounted up some new XTR Trail brakes and XT Ice-Tech rotors on a new bike and during the bed-in process the front brake started howling like mad. I live on a hill, and after 5-6 descents, the howling started. I did a total of 15 runs and it never quieted down. Rear brake seems fine. Any ideas or tips? Is this normal? Will it quiet down as I start to rack up some miles? Was planning to take the new ride out tomorrow after work but the howling is going to scare the beejezzus out of all the wildlife on the trails.

    I took the brakes right out of the package and mounted them up so the front hose is way too long still and needs to be cut. This wouldn't have anything to do with it, does it?

  2. #2
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    New XTR brakes howling during bed-in

    Did your brakes come with the organic shimano pads, by any chance?


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  3. #3
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    Pretty sure they are metallic. Don't have the box in front of me but that's what I recall seeing labeled on the side of the box. Did some searches last night and saw this issue of the leaking problem at the hose/banjo bolt interface. That would suck if my brand new brakes are exhibiting that problem before I have even ridden them. I will need to look tonight after I get home to see if I can spot any residue on the rotors.

  4. #4
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    Question did you install or the bike shop? Next if you did, did you have to cut the lines and rebleed? And if you did that did any fluid get on the pads. If all that was done correctly and not the issue then when breaking in the pads and rotors you say you have a hill, how much of a hill too big and you could be bedding them in to hard. get some fine sand paper 150 to 220 grit and give them a light sanding if they looked glazed over. Also get some ISO and give the rotors a wipe down as well. Try bedding in the pads again. When bedding in you should try to be on flat ground and never coming to a complete stop. Do this 8 to 10 times. go fairly strong apply the brakes lightly at first and stronger as you start ending the bedding in process. Hopefully this gets rid of your squeal. If by chance you did end of getting fluid on your pads you can try sanding them down as explained above and or cook them out in an oven at least 500 F for about 20-30 mins. This has worked sometimes for people (including myself). Good luck

  5. #5
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    I use a one-man shop and the owner/mechanic installed them for me as a last minute favor since he was going out of town for a week. He did not have time to cut the hoses though and so I am planning to take it back to him next week, so there was no re-bleeding that had to be done.

    Based on your reply, it's possible I was bedding them in too hard because I do live on a pretty steep hill. Didn't have my garmin on but I was probably hitting 20-25 mph. I applied the brakes for a period of about 10 seconds, gradually increasing power but not coming to a complete stop.

    I had read some articles on how to bed and thought I was doing it the right way. Maddening!!

    Thanks for the suggestions regarding the sanding of the pads and the cleaning of the rotors. I'm going to ride the bike today after work and then have a look this weekend.

  6. #6
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    New XTR brakes howling during bed-in

    Seems like you've glazed the pads... Whenever I bed in pads I'll hit maybe about 17mph max, especially with organics. I'm led to believe the resin that hold them together has a relatively easy glazing point. But seeing as they're brand new Id rough them up with some sandpaper. But to be honest, I've never had good luck with Shimano's organic pads, the slightest but of contamination just completely ruins them...(I went through about three sets in a month...)

    I'm not sure what style of riding you do, but for XC and light AM stuff the EBC red compound pads are simply amazing IMO. Probably better with ceramic pistons and ice tech rotors.


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  7. #7
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    I just mounted the same brakes and same rotors I also had the howling when bedding the pads from the front only.
    I just got back from a 20 mile ride and they did not make any noise.
    Nice and quite with awesome power.
    I have the free stroke screw backed out so the modulation is really nice.
    Only issue is the free stroke screw could fall out, guess I need to Loctite it.
    Very happy with brakes!

  8. #8
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    I have the same brakes and rotors and my rear was noisy until I replaced the pads with Shimano organic pads, they are silent now. Hopefully I won't need to replace them often.

  9. #9
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    Update to my issue: I rode the bike on the trails for the first time on Friday. After some squealing on the first couple of hard braking events, I did not hear the brakes again for the rest of my 20+ mile ride. I then rode it again yesterday and today, covering another 55 miles and the brakes remained dead quiet. All in all, 77 miles and 12k ft of elevation over the first 3 days. So it appears that similar to Phantomtracer, whatever was initially causing the howling appears to have passed - keeping my fingers crossed. BTW, performance on these brakes has been outstanding! Hope they remain nice and quiet.

  10. #10
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    Yup, mine howled a bit at bedding also, but was fine out on the trail. Been good with +300 miles...

    Side note: I contaminated some pads on an XT set a few months back. Tried BrakeKleen and the baking method with no luck. Decided to take my chance by heat cycling the brakes going down a long, steep but safe hill multiple times. Getting up to speed, then braking hard to a slow many many times. They feel good as new now and continue to do so.

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