99 vfr front wheel brake drag problem

Discussion in 'Mechanics Garage' started by cosu23, Jul 14, 2012.

  1. cosu23

    cosu23 New Member

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    Hi there
    i have a problem with my 99 vfr. the front wheel presents a serious brake drag. when on central
    stand with the front wheel suspended i get sometimes 1/4 turn and sometimes 1 and 1/4 turn max.
    I've verified on another bikes (also vfr rc46) and got 2-3 complete turns. I've changed the brake fluid
    and bled the system, I've cleaned the calipers pistons (on spot - not by removing them), I've checked the
    front wheel alignment .... and the same.
    The strange thing, as i have mentioned before, is that the brake drag varies, sometimes it is stronger
    sometimes weaker but always there.
    If you have any ideas regarding my problem please reply.
    Best regards from Romania
    costin
     
  2. skimad4x4

    skimad4x4 "Official" VFRWorld Greeter

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    Inherently brake drag is probably due to the pads catching the disc at some point as the disc rotates - if its really bad and this has been happening for a long while then one section of the disc may show increased wear/glazing. Check both sides of each disc in good natural light.

    What sort of mileage has the bike done and what sort of riding are you doing - track use will heat up stock brakes very quickly? Have the brake discs ever been replaced or are they the original set? If the mileage is high, then I would suspect disc wear has allowed the brake discs to become thin enough to be distorted. This would result in the wheel running freely at some part of the rotation but catching the pads at others. Support the bike on centre stand - place a weight on rear seat to keep front wheel clear off the ground, and monitor closely the pad/disc gap and the disc/fork distances as you rotate the wheel. Any substantive variation in the gap probably indicates its time for new discs. Check both sides!

    Repeat the check noting the gap between the tyre and the fork if that varies significantly then the wheel could be buckled.

    If the gap seems consistent, then try and identify where the drag is occurring. Stick a piece of masking tape on the tyre/rim to note locations where you can feel there is/is not pad drag - if the drag repeats in the same place each rotation then it suggests one or more discs wheel may be buckled or just possibly there may be an issue with the bearings allowing the pads to catch.

    (One related thought just in case you have recently replaced the discs - did you thoroughly clean the mounting surfaces? Crud trapped on the mounting pints could possibly result in the disc being slightly mis-aligned - same applies to the pads if they don't back off fully after application.)

    Sorry this is probably one of those issues where you will have to progressively eliminate potential causes until you eventually resolve the problem. If you know someone with a similar bike then swapping over the front wheel would provide a quick way to eliminate a lot of possible issues. Let us know how you get on.




    Skimad4x4
    Proud member - 6th Gen Militia # 218 - European 1st Division
     
  3. pjvtec

    pjvtec New Member

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    :high5: Nice job skimad4x4
     
  4. kennybobby

    kennybobby New Member

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    Line Pressure Relief

    Did you clean out the tiny return orifice in the master chamber? There may be a small metal plate in the bottom of the master reservoir that must be removed to see the hole. If this orifice is clogged you will have brake drag such as you have described.
     
    Last edited: Jul 15, 2012
  5. squirrelman

    squirrelman Member

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    Symptoms suggest a warped/bent rotor, not too unusual.
     
  6. tinkerinWstuff

    tinkerinWstuff Administrator Staff Member

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    forks clamped in the correct position on the axle? The forks can be clamped on the axle in such a way that the calipers are pressing against the rotors and having constant drag.
     
  7. Pliskin

    Pliskin New Member

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    You mentioned that sometimes you get 1/4 turn, and sometimes a full turn. These guys know way more than me, so I'd listen to them. Sounds like a piston in one of the calipers is hanging up. What are there - 4 pistons per caliper? Only takes 1 to screw it up, and since the sticking/grabbing seems to vary, that's what my money is on.
     
  8. cosu23

    cosu23 New Member

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    first of all thank you for your quick replies.

    skimad4x4
    mileage is around 37000km, my ridding stile is closer to touring than sport.
    the drag is constant. when my hand is off the brake it feels like it is still
    applied a little.
    with the front wheel suspended if i press by hand the calipers against the
    brake disk (like you have to do when you remove the caliper) and then rotate
    the wheel it can be seen a slight deformation of the disks but i think it is in the
    service limits.
    I will check the distances as you told me.
    thank you.

    kennybobby
    i will check the pressure relief, it has not been done so far.
    thank you

    tinkerinWstuff
    this spring i have changed the head bearing and the fork oil, I've gone though
    all the steps from the manual.... I'll check again the front wheel alignment

    thank you all again, today after work i'm gonna check all those things.
    best regards

    costin
     
  9. cosu23

    cosu23 New Member

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    hi there
    as promised here is the update regarding my problem.
    I've cleaned the front brake pump and the front calipers pistons and in seems 90% ok :)
    for now i'm gonna leave it be...
    the only thing that i could do in the future is to change the front caliper seal kit and clean the
    brake lines...
    thank you all again for your replies
     
  10. taylor65

    taylor65 New Member

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    I have a 98 and have similar problem but I don't think mine is that severe. I checked the prices for new seals and it will be around 60 buck as there are six pistons on the front of a 5th gen. I e checked my alignment and that seemed to help and I also changed brake pads which also helped a lot but I will be watching this thread to see if you track it down. Thanks for the in direct advice everyone.
     
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