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  1. #1
    Phil from San Diego
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    Nylon rope got tangled in my Formula K24. =/

    During my last trip to Mammoth mountain bike park, a section of nylon rope used to mark the end of a downhill trail was broken loose by someone. It got tangled in my rear dérailleur, tore it off.. and part of the rope also got in between the brake pads and rotor. As that happened, I immediately felt drastic lost of braking power in the rear brakes. I managed to cut/pull off the ropes, removed the mangled dérailleur, and rolled back to the bike shop.

    After getting a replacement dérailleur, I continued to ride out my last day.. I didn't have replacement pads/rotors so I was hoping the nylon coating my rotors/pads would wear off after a few more runs.. but it never did.

    Now my rotor is pretty much all black.. I took the rotor/pads off and tried to sand all the contact surfaces with metallic sand paper. The brake pads were the sintered type and looked ok after I sanded them. The rotor remained dark gray but I think I've sanded off the black coating.. I then used my Dremel with the wire brush to see if that would work better to restore the surface but that didn't do much. by switching to the blue/gray polishing wheel.. I could completely remove the haze to reveal the shinny surface below.. however, the surface looked a bit too shinny so I stopped not wanting to kill the rotor with a polished surface...

    So I figured I better ask for help and see what you guys can recommend. I have a brand new set of pads I could use but if there's still burnt on nylon residue on the rotor, I imagine that would probably kill those pads.

    If anyone know of a good way to save my rotor (aside having to spend an hour or two hand sanding the rotor.. which probably will work) I'm all ears and I thank you in advanced!

    Phil.

  2. #2
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    I'd say....

    probably the most certain way to make sure you won't be getting any nylon residue on the new pads is to replace the rotor. The next best solution is going to be hand sanding as you noted. But still there are no guarantees that even careful hand sanding will remove everything. The problem with nylon when it gets hot enough it turns to a liquid. After all that's all nylon fiber is, a super cooled liquid synthetic. That liquid can run into scratches and pores in the metal of the rotor that you can't even see. And it'll stick there until you forceably remove it. And once it's cooled enough to be solid again it like to STICK! Oh and also keep in mind that it is a petroleum based sythetic fiber. While it doesn't act like oil, it started out life as oil and does retain some of those properties.

    If it were me, I'd replace the rotor to be on the safe side.

    Good Dirt
    "I do whatever my Rice Cripsies tell me to!"

  3. #3
    Knollician
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    Since you have the sintered pads, simply torch them. Hold the pad with a pair of pliers and burn them with the torch until they glow. Then torch the rotor. You will see the residue burn off. Your brakes will be like new.
    "Three balls at once...who knew?" - Cotton McKnight

  4. #4
    Phil from San Diego
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    oo... I like your suggestiong TiSSer.. that sounds fun even if it doesn't work.. =)

    think that would work Squash? would the residue burn off or still remain on the rotors?


    Phil.

  5. #5
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    sounds good to me just keep even -low heat on it or it will warp for shure. but it will no doubt take any residue off. good luck

  6. #6
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    It's worth a try....

    but it likely won't work. The unfortunate thing about petroleum based sythetics is they leave residue behind even when heated. The temps that have to be reached to completely eliminate all residue just isn't possible with a common torch. Nor is it possible for the rotor or the pads to withstand those temperatures. But you might get enough of the bad stuff off for it to work. Like I said, worth a try. If it doesn't work you aren't any worse off than you are now.

    Good Dirt
    "I do whatever my Rice Cripsies tell me to!"

  7. #7
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    don't torch your rotors unless you want them to fracture dramatically.

  8. #8
    Phil from San Diego
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    Since i didn't have a high power torch.. I used a small pen sized torch that doubled as a soldering iron. Couldn't get the rotor hot enough to glow.. and nothing looked liked it was getting burnt off..

    So i figured I had to get the black stuff physically off the rotor. Digging in my Dremel kit, i found some sanding disks/wheels and gave those a try and it worked. It wasn't fast.. think I spent an hour on both sides of the rotor and went through 4 sanding disks. After that, I used a 3M med/fine sanding sponge/block to make the surface more even.

    The rotor looked really good and almost like new again after that.

    Installed everything back together and gave the bike a short ride up/down the street. I was able to lock the brakes skid after a few minutes! =) It'll probably take a ride or two for it to fully break in again but looks like it's all good now.

    Thanks again for the suggestions. =)

    Phil.

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