what to do when brake piston would not return to place?

Molala2
Molala2 Posts: 8
edited November 2011 in MTB workshop & tech
as in my terkro draco disc brake...the pistol would not return to the original position after braking and keep rubbing the brake disc..... :(

Comments

  • nicklouse
    nicklouse Posts: 50,675
    clean the piston wals with a small amount of brake fluid on a bud. careful you do not push the pistons out though.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • delcol
    delcol Posts: 2,848
    i got a tool from superstar components that pushes the pistons back in.. it's friendlier on the pads/pistons than the screwdriver method....
  • Anonymous
    Anonymous Posts: 79,667
    Got the same from Superstar with my last order of pads. Quite handy and less damaging than a flat bladed screwdriver so can get away using it on pads you want to keep.

    Anyway, if cleaning as suggested, remove the pads first! And don't get any fluid on the rotors either.

    Could be many other reasons though.

    For pad alignment, assuming the calliper is aligned okay, then trick I use if it's rubbing for no good reason is push the pistons back, put wheel in and stick two bits of card either side of the disc (business card kind of thickness), then apply brakes a few times, take the cards out and chances are it will be fine then.

    Can also use the same technique to align the calliper, doing the same with the calliper bolts slackened, apply brake and hold lever (or tie to bar), then tighten the bolts, release lever, remove cards and job done. Just torque bolts to spec then.

    Might also get rubbing sound when it's actually muck from a muddy ride. Also sometimes they rub a bit, but applying the brakes a few times or just riding in general and it can go away.

    Unless you have Juicys, which are awful. Then you get endless problems with rubbing discs and dodgy pistons.