User Tag List

Dislikes Dislikes:  0
Page 1 of 2 12 LastLast
Results 1 to 20 of 27

Thread: Cannot get rid of brake drag

  1. #1
    Member wheel_of_steell's Avatar
    Join Date
    May 2013
    Location
    Boogaroon
    Motorbike
    Bandit 1200S
    Liked
    69 times
    Posts
    428
    Post Thanks / Like
    Mentioned
    5 Post(s)
    Tagged
    0 Thread(s)

    Cannot get rid of brake drag

    I've had the same problem across multiple bikes, so I'm aware what (who) the common denominator is in this equation. I'm just out of ideas for things to check. Root cause of the problem on a gs500 was a flake of paint inside the master cylinder had fallen over the return hole. Root cause of the problem on a bandit 1200 was shitty tokico 6 pots corroding and needing a rebuild.

    Problem: A short ride around the block creates brake dragging sounds and a hot disc even without touching the brake lever. With the front wheel in the air, a hearty spin of the front wheel only gets about 1-1.5 turns before coming to a stop. If brake pads are retracted or caliper removed, the same effort returns 5+ turns before the wheel stops.

    Things I've tried to remedy this so far:
    -try new brake pads
    -meticulously clean the caliper and pistons
    -flush and bleed brake fluid with quality stuff of correct grade
    -grease sliding caliper pins and brake pad mounting tabs with bendix brake grease
    -ensure master cylinder is not overfilled
    -ensure master cylinder vent hole is not blocked
    -plane off 1mm from new pads in case they're oversized
    ???

    Send thoughts and prayers
    Quote Originally Posted by devolved
    I just crashed into a schoolbus full of kiddies, killed them all, raped them, set them on fire and now I'm pissing on their charred remains.

  2. #2
    Member Gim's Avatar
    Join Date
    Jun 2016
    Location
    Norther Suberbs
    Motorbike
    Kawasaki Ninja
    Liked
    0 times
    Posts
    515
    Post Thanks / Like
    Mentioned
    14 Post(s)
    Tagged
    0 Thread(s)
    Warped disc ?


    Sent from my iPhone using Tapatalk

  3. #3
    Member GsxInShed's Avatar
    Join Date
    Jun 2010
    Location
    Next to the big hole in the economy
    Motorbike
    (TY-250- RD350LC- Gsx 750 esd) Current -Gsx 250 SSM GSX 1100 EFE
    Liked
    304 times
    Posts
    8,352
    Post Thanks / Like
    Mentioned
    36 Post(s)
    Tagged
    0 Thread(s)

    Push pads back , gently...so they don't contact rotor.

    Spin wheel.

    apply and release brakes--watch pad movement.

    Spin wheel.

    annd then....?
    " Imagination is the seed of life..."

  4. #4
    Member Loud's Avatar
    Join Date
    Dec 2009
    Location
    South. Just.
    Motorbike
    Aprilia RS250, GSXR750 Slabbie
    Liked
    906 times
    Posts
    4,917
    Post Thanks / Like
    Mentioned
    96 Post(s)
    Tagged
    0 Thread(s)
    Some drag is normal. But 1-1.5 turns and a hot disc seems unusual - for the front wheel.

    Are you talking about the front wheel? Is there any sign of pad glazing and, if so, is it on both pads or just one? Have you (carefully, with precautions) tried operating the caliper/s when removed from the disc and checked for smooth movement of all pistons?

    Could be master cylinder seals and it needs a rebuild. Won't be pads. Could be the calipers are sticking because they need a clean out and rebuild.
    Click Link for My Bikes:

    Aprilia RS250
    1985 GSXR750 "Slabbie"

  5. #5
    Member GsxInShed's Avatar
    Join Date
    Jun 2010
    Location
    Next to the big hole in the economy
    Motorbike
    (TY-250- RD350LC- Gsx 750 esd) Current -Gsx 250 SSM GSX 1100 EFE
    Liked
    304 times
    Posts
    8,352
    Post Thanks / Like
    Mentioned
    36 Post(s)
    Tagged
    0 Thread(s)

    could be the lack of freeplay at the lever??

    to be fair the M/c piston should be fully retracted with hand off the lever...as should the caliper pistons...although they will be held by the square section seals ( on the rotor to a certain degree )

    Are they floating rotors? are the buttons clean free to move?

    Loosen calipers check again if drag is evident to test for fork/caliper preloads..( bent or twisted fork in triples....can cause misaligned caliper.)

    ( so don't undo...just crack the bolts redo finger tight -- works better if you have an assistant to hold brake lever on) make sure to clean locktite and retorque when done...eh?

    OR might just be simple shit as loud said..
    " Imagination is the seed of life..."
    Likes =Maz= liked this post

  6. #6
    Member wheel_of_steell's Avatar
    Join Date
    May 2013
    Location
    Boogaroon
    Motorbike
    Bandit 1200S
    Liked
    69 times
    Posts
    428
    Post Thanks / Like
    Mentioned
    5 Post(s)
    Tagged
    0 Thread(s)
    Thanks for the input guys. I'll check that the forks/disc/caliper/axle are all sitting square and not warped.

    The bike in question is an nc700 with 20k on the clock. We are dealing with the front wheel, which is a nissin 3 pot sliding caliper on what seems to be a fixed disc. The pads I removed are the original nissin pads which had more or less even wear. The bike did sit for a while before I bought it but on the whole it's not super old, abused, or high mileage so that might help with any suggestions.
    Quote Originally Posted by devolved
    I just crashed into a schoolbus full of kiddies, killed them all, raped them, set them on fire and now I'm pissing on their charred remains.

  7. #7
    Member
    Join Date
    Apr 2006
    Location
    ...
    Motorbike
    ...
    Liked
    5260 times
    Posts
    22,205
    Post Thanks / Like
    Mentioned
    34 Post(s)
    Tagged
    0 Thread(s)
    Is it a linked brake system with one piston operated by the rear brake?

    Fixed disc won't "wobble" around and knock the pads back like a floating disc...

  8. #8
    Member GsxInShed's Avatar
    Join Date
    Jun 2010
    Location
    Next to the big hole in the economy
    Motorbike
    (TY-250- RD350LC- Gsx 750 esd) Current -Gsx 250 SSM GSX 1100 EFE
    Liked
    304 times
    Posts
    8,352
    Post Thanks / Like
    Mentioned
    36 Post(s)
    Tagged
    0 Thread(s)

    Is it pre 2014?

    Linked brakes-- google says they were dropped after 2014--shit idea on an adventure bike ???? Dunno.
    " Imagination is the seed of life..."

  9. #9
    New Member
    Join Date
    Jun 2017
    Motorbike
    2016 Yamaha R3, 1990 Honda MC22(L)
    Liked
    0 times
    Posts
    6
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I've had those symptoms on my rear brakes before. The cause was old brake hoses. Brake/hydrolic hoses come double skinned to prevent bursting or punctures and sometimes on old brake hoses the inner skin can collapse where you can still force fluid through lever pressure but the return press is doesn't have the force to push pass the collapsed section of hose so the piston retracts so slowly or not at all but will retract easily if you were to lever the pads off the rotor. The symptoms only became significantly noticable when filtering through 15km of rush hour traffic type conditions where I'd be using a lot of rear brake to smooth out my speed in low gears for long distances. Hope that helps
    Likes Dangee711 liked this post

  10. #10
    Member Hillz's Avatar
    Join Date
    Sep 2010
    Location
    Mundaring
    Motorbike
    ZX10R, DRZ400SM, Speedmaster 865, YZ250
    Liked
    0 times
    Posts
    2,190
    Post Thanks / Like
    Mentioned
    24 Post(s)
    Tagged
    0 Thread(s)
    get ya foot off the lever
    Likes $10 is almost $20 liked this post

  11. #11
    Member SomeBloke's Avatar
    Join Date
    Feb 2012
    Location
    Perth, Western Australia, Australia
    Motorbike
    2003 R6 Road bike; 2008 R6 Race bike
    Liked
    154 times
    Posts
    1,371
    Post Thanks / Like
    Mentioned
    10 Post(s)
    Tagged
    0 Thread(s)
    The mechanism that makes the piston return is the flex of the piston seals at the calliper. Have you replaced them? They get old and stiff over time and flex less.
    "Life begins at the end of your comfort zone."


  12. #12
    Member BusaSteve's Avatar
    Join Date
    Dec 2010
    Location
    WA NOR
    Motorbike
    MT09
    Liked
    317 times
    Posts
    5,280
    Post Thanks / Like
    Mentioned
    37 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by SomeBloke View Post
    The mechanism that makes the piston return is the flex of the piston seals at the calliper. Have you replaced them? They get old and stiff over time and flex less.
    That and the absence of fluid pressure...the master cylinder vent port may be slightly clogged or the piston return sping may be weak
    Smoke me a kipper...I'll be home in time for breakfast

  13. #13
    Member Loud's Avatar
    Join Date
    Dec 2009
    Location
    South. Just.
    Motorbike
    Aprilia RS250, GSXR750 Slabbie
    Liked
    906 times
    Posts
    4,917
    Post Thanks / Like
    Mentioned
    96 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by SomeBloke View Post
    The mechanism that makes the piston return is the flex of the piston seals at the calliper. Have you replaced them? They get old and stiff over time and flex less.
    There are two seals - a dust seal and a wiper seal. Neither do what you seem to be describing. If they did then you wouldn't have to push the pistons in to the fully retracted position before changing brake pads - they would already be retracted because of the seals... which they aren't. If this were the case though there would be a large gap between worn pads and rotors, which there is not - even when they're down to metal they'll still be skimming the disc.

    The dust seal simply keeps brake dust and road dirt from accumulating around the exposed piston, and reaching the wiper seal. It has no strength, it's made of thin rubber, that's why it can tear.

    Hope that was informative in a nice enough way
    Click Link for My Bikes:

    Aprilia RS250
    1985 GSXR750 "Slabbie"

  14. #14
    Member SomeBloke's Avatar
    Join Date
    Feb 2012
    Location
    Perth, Western Australia, Australia
    Motorbike
    2003 R6 Road bike; 2008 R6 Race bike
    Liked
    154 times
    Posts
    1,371
    Post Thanks / Like
    Mentioned
    10 Post(s)
    Tagged
    0 Thread(s)
    The seals flex... That's why nominal clearance is tiny. That clearance is seal deflection.
    "Life begins at the end of your comfort zone."


  15. #15
    Member Loud's Avatar
    Join Date
    Dec 2009
    Location
    South. Just.
    Motorbike
    Aprilia RS250, GSXR750 Slabbie
    Liked
    906 times
    Posts
    4,917
    Post Thanks / Like
    Mentioned
    96 Post(s)
    Tagged
    0 Thread(s)
    That's an interesting diagram. I'm intrigued, I genuinely had no idea the wiper seal did that. From your post I thought you were suggesting the dust seal sprung the piston back in the whole way. My bad.
    Click Link for My Bikes:

    Aprilia RS250
    1985 GSXR750 "Slabbie"

  16. #16
    Member
    Join Date
    Aug 2018
    Location
    Perth
    Motorbike
    R6
    Liked
    0 times
    Posts
    40
    Post Thanks / Like
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    I had a similar problem with my car. Turned out to be torn dust seal allowing dirt to get into the piston bore. I rebuilt the caliper with new seals and scotch bright the piston to clean it and problem solved.

    Could be any number of problems though as mentioned on here.
    Last edited by Dunc; 13-10-2018 at 05:51 AM.

  17. #17
    Member SomeBloke's Avatar
    Join Date
    Feb 2012
    Location
    Perth, Western Australia, Australia
    Motorbike
    2003 R6 Road bike; 2008 R6 Race bike
    Liked
    154 times
    Posts
    1,371
    Post Thanks / Like
    Mentioned
    10 Post(s)
    Tagged
    0 Thread(s)
    All good, it's a pretty obscure mechanism.

    If the seal pulled the piston all the way back I think I would have to buy a brown seat.
    "Life begins at the end of your comfort zone."


  18. #18
    Member BusaSteve's Avatar
    Join Date
    Dec 2010
    Location
    WA NOR
    Motorbike
    MT09
    Liked
    317 times
    Posts
    5,280
    Post Thanks / Like
    Mentioned
    37 Post(s)
    Tagged
    0 Thread(s)
    I believe there is a slight sucking action on the piston to make it slide in.....
    Smoke me a kipper...I'll be home in time for breakfast

  19. #19
    Member GsxInShed's Avatar
    Join Date
    Jun 2010
    Location
    Next to the big hole in the economy
    Motorbike
    (TY-250- RD350LC- Gsx 750 esd) Current -Gsx 250 SSM GSX 1100 EFE
    Liked
    304 times
    Posts
    8,352
    Post Thanks / Like
    Mentioned
    36 Post(s)
    Tagged
    0 Thread(s)

    .....if you have more than 1 piston in a caliper...shit changes multiple seals resisting piston return at all times.

    pads will usually be "in contact" with the rotors....self adjusting for wear on the pad. Use silicon dab on rear of pad to hold 'em against the caliper piston.....make certain the pad will move freely in the caliper.

    If all the systems have been checked as ok..some contact will be normal....I use water to flush my brake bits,in fact, I clean and test 'em in the kitchen sink...under water to see if they bleed ok before refit.

    A master cyl is simply a pump to move brake fluid to the calipers....add linked shit with abs..some changes occur.
    " Imagination is the seed of life..."
    Likes GreenMeanie liked this post

  20. #20
    Member Para045's Avatar
    Join Date
    Oct 2006
    Location
    City of Wanneroo
    Motorbike
    98 TITANIUM CBR1100XX SUPERBLACKBIRD
    Liked
    1150 times
    Posts
    16,178
    Post Thanks / Like
    Mentioned
    77 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by BusaSteve View Post
    I believe there is a slight sucking action on the piston to make it slide in.....
    Ah I see what you mean

    Spoiler: show
    #1 Gold Ticket Holder for the Barfridge Fan Club
    Quote Originally Posted by Phildo View Post
    Noted. We'll check back on that one in three years
    Quote Originally Posted by filbert View Post
    i'll pretend you didn't know she was 13

    98 BADASS TITANIUM BLACKBIRD - Past bikes 1982 XS250 Yamaha & 1983 CB750F with 900 motor
    Ozblackbird.net Administrator

Bookmarks

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •