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I just bought a new mountain bike equiped with Shimano M365s and RST Blaze fork and I've been through the bedding process.

I noticed that my front brake is rubbing a lot, and when i tried to fix it, I realised that the caliper is not seated straight on the fork. Also, the disk is a bit bent but i suspect that's coming for the hub itself as the bike is brand new.

When i try to center the caliper it sits perfectly on the disk, but when i tighten it, it gets a bad angle and rubs unevenly on the disk.

I suspect it's something to do with the washers as they not sit straight when the bolt is tightened.

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    Normal procedure that you probably followed: Un-tighten the two bolts, pull the the brake lever while softly tapping the calliper. KEEP the lever pulled and re-tighten the bolts in two steps at least. Then only release the lever. – Carel Dec 24 '16 at 14:35
  • Yeap that's correct – Alextsil Dec 24 '16 at 14:55
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    Do the calipers come with conical washers? – ebrohman Dec 24 '16 at 15:05
  • yes. If you look really closely at the bottom one, you can see it's not really straight. – Alextsil Dec 24 '16 at 15:23
  • Concave/Convex washers need a pair on each bolt - i.e. a Caliper needs 8 washers. Your mount is missing the bottom ones. I don't recall any Shimano braking using these - they are mostly used on Avids. My first reaction is check the brakes are correctly assembled accornding to Shimano installation instructions. I have seen this done by a bike shop when the bolts were too long - I presume fitting washers was easier, quicker or cheaper than finding the correct mounting bolts. – mattnz Dec 24 '16 at 23:33
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First double check the wheel is fully seated in the frame. If it is, and the caliper is sitting at an angle no matter what you do, it's a sign the post mounts need to be faced, which essentially is a shop job unless you buy a fairly expensive tool. This isn't common on new suspension forks for whatever reason, although you see it out of the box on frames quite a bit presently. Hopefully whoever you bought it from just takes care of it for you.

A related problem arises if the mounting bolts have been overtightened and caused the post mount or adapter to dent a depression into the surface of the caliper. That doesn't really happen on relatively chunky mounts like these though, more the dainty rounded ones that some bikes use.

  • That is some great information. I had no idea that "facing" was a thing. I will go the shop but most likely they will call me "crazy" (pretty common in my 3rd world country). Thanks a lot, i will let you know! – Alextsil Dec 24 '16 at 15:36
  • I took it to the LBS and the mechanic trimmed the fork mount and added a washer to compensate. Took 5 mins. Thanks :) – Alextsil Dec 27 '16 at 14:20

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