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I've just been finished building a bike (by decath lol) and having been out on it a few times the front disc pads/rotor is rubbing pretty severely I know discs are meant to rub a little but this is very loud the rotor doesn't appear warped or bent, and I can't figure out how to adjust them by slackening the pads off a little ...
anyone help?.. the back has the same setup exactly and is fine
could there be too much fluid in the system is there a way to adjust them?
cheers..
The M525s are pretty non adjustable from memory. Have you made sure the caliper is centered on the disc, so the disc is in the middle of the slot in the caliper? If its moving from side to side, then your disc is possbly warped (Although I've had a disc mount on a hub which was slightly off true, so looked like the disc was warped when it wasn't)
Try to realign your calipers - using a 5mm allen key.
Loosen the bolts that hold the caliper onto the frame, so that it moves easily by hand.
Apply the brake, and hold it there
Tighten the caliper bolts
Release the brake.
Ride your bike
I used to use beluga's method on my 525s, but I find that slackening off the caliper bolts a tiny bit and aligning by eye works better for them now.
If you spin the wheel slowly once you've done the best job of centering possible you'll see any side to side movement between the pads which would indicate a warped rotor.
If its not an alignment problem as above, then you may have squeezed the pistons out a bit far at some time in your build process (squeezing levers while wheel/rotor is out is the usual mistake, or putting new/thicker pads in without re-setting the pistons!). If this is the case, the pads will be too close to the rotors and no amount of alignment will be able to stop them rubbing! They won't return to normal by themselves, you'll need to take pads out and push pistons back in manually with a plastic tyre lever or similar. Then remount it all and pump the brakes a few times to get them to the right spacing for riding. If the pistons won't go back in then the system is overfilled (did you do a bleed of the brakes as part of your build?), and you'll need to remove the reservoir cover before pushing pistons in, and let the excess oil spill out.
just got back from a ride out and having just come a cropper while i was out, the wheel ended up sitting to the right by about 3 / 4 mill all centered not buckled etc, had no idea what the problem was thought maybe id twisted the forks but after playing with it for a while i nipped to halfords and got one of the guys to chck it over had the wheel off then put it back on it was fine no idea why, as for the rotor rub he also sudgested belugabob method but at the min it seems fine so maybe the wheel wasnt on quite right or theres a sticky pad, becuase before i set out today it was rubbing when i was playing with it and when i turned up at the route with it on the bike wrack it had stopped rubbing, only to do it later on..?
seems good now thanks for heads up..