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Front brakes are a drag..

Discussion in 'Technical and Troubleshooting Torque' started by smidge, Nov 26, 2012.

  1. Pun Intended. Front brakes on my VT250F seem to be dragging. I got myself a full replacement set of front calipers, lines and master/lever from Japan and installed it, its improved but its still a little draggy.

    I've flushed the fluid, done everything except pull the actual calipers apart (seals are quite expensive so this is last resort)

    is there anything else i can check before i set fire to the bike?

    should the front wheel spin quite freely? to be honest i've never actually checked until now. With the callipers completely off the wheel will spin 10+ times with a decent push, with calipers on its lucky to get around once or twce.

  2. Is the dragging consistent, or does it seem to fluctuate?
    If it's the latter then a warped rotor might be the cause.
  3. its fairly consistent, i couldn't see any obvious runout and there's zero brake shudder.

    I'm not sure how far back the pistons are supposed to go once the brake lever is released but its almost like they need to go back in an extra 1mm. the pads would always be in contact with the rotor anyway right? so some heat is going to be generated...
  4. The piston seals in the calipers are what retract the pistons. Old seals will be weak and distorted and not doing their full job. Also there is the potential for one or more pistons to be seized or stiff in their bores. A caliper rebuild is what you should be doing, or getting someone to do for you.
  5. $60+ a set for the seals, guess i'm rebuilding them !
  6. It could be a bunch of things and none of the following is specific to your bike. Sometimes the forks are slightly misaligned, you can straighten it up by loosening the axle/pinch bolts and bounce the front end on the ground a few times, do them back up in the right order while front wheel is on the ground. Sometimes loosening the top triple clamp helps too, then retorque top triple clamp, then the axle, etc. Seals could def be an issue at that vintage, as could runout on the rotors (needs more than a visual check). If they are semi-floating make sure the buttons arent full of brake dust which prevents them from floating enough between the pads. Not sure if the calipers can be moved on the forks but if so, check they are aligned with the rotor by slowly applying the front brake when spinning the front wheel and then torquing them up with fr brake still applied. And sounds obvious but make sure the wheel is the right way around, some front wheels look identical if flipped but the spacers can be out by a mm or so one direction or the other.
  7. all good tips thanks Richi, i'm pretty keen to exhaust all other possibilities before pulling the calipers apart. Done it a few times and its one of my least favourite jobs. I always have lots of trouble getting the Pistons back in properly (on cars and bikes)

    i've cleaned them and they come out and go back in fairly easily, so i know they aren't totally seized

    will give all those suggestions a go
  8. #8 phil01, Nov 26, 2012
    Last edited: Nov 26, 2012
    i am reading this thread and wondering you think you have a problem and
    what alerted you to the problem you think you have?.
    have you /are you riding the bike? and if so what is the actual problems
    /symptons you have?
    i say this because of all the stuff i read doesnt actualy mention a problem, its
    likely there isnt one