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Thread: K75RT 92 w/ABS any trick to bleeding rear brake

  1. #1
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    K75RT 92 w/ABS any trick to bleeding rear brake

    K75RT 92 w/ABS any trick to bleeding rear brake. New to me, was told the ABS might be turned off. Just finished replacing everything in the tank, got it started, now no rear brake. Sat for years in a garage. Just trying to bring it back to life.
    Dave

  2. #2
    I used a Mity-vac to remove the old fluid and draw in the new. The ABS unit has a separate bleed nipple and holds a tablespoon or so of fluid as I recall. Bleed the calipers and the unit. If it still does not work you may have to rebuild and or clean the calipers. I don't recall any real problem. Good luck.
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  3. #3
    #13338 PGlaves's Avatar
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    Those brakes will self-bleed with gravity flow alone if you have the patience to sit there and watch it and keep the reservoir full at the top.

    My luck with a vacumn device has been dismal - they pull bubbles past the bleeder threads and I can never tell when I am really done.

    The biggest problem most people have is letting air in from the top and then having to bleed and bleed and bleed to get the air back out.

    If there is air in the system you may need to reposition the caliper so that the bleed screw is pointing stright up to get it all out.
    Paul Glaves - "Big Bend", Texas U.S.A
    "The greatest challenge to any thinker is stating the problem in a way that will allow a solution." - Bertrand Russell
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  4. #4
    K Bikes Complex by Choice cjack's Avatar
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    I get good results by having the caliper at the lowest point and pushing the brake pads in and then pumping them out (against a disk or disk thickness). And doing that about a half dozen times. That way you are not fighting gravity and the air trapped in the caliper gets pushed out. Keep the top on the reservoir while doing this...
    R1200GS LC Rallye
    Jack Hawley MOA and RA #224, KE9UW ("Chuck")

  5. #5
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    Thanks for the help, I'll give it a try.
    Dave

  6. #6

    Exclamation Possible ABS failure

    My rear brake wasn't there on my '92 K75RT when I bought it.....push on the pedal and nothing. Unplugged the ABS brain and the brake operated wonderfully. Easy to do....just pull the thing out and unclip the big connector....then take a ride. If your rear brake works, it's the ABS brain or the rear modulator that's the problem......long threads elsewhere regarding those issues.

    Good luck!

  7. #7
    BMWNUT grw's Avatar
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    Quote Originally Posted by PGlaves View Post
    Those brakes will self-bleed with gravity flow alone if you have the patience to sit there and watch it and keep the reservoir full at the top.

    My luck with a vacumn device has been dismal - they pull bubbles past the bleeder threads and I can never tell when I am really done.

    The biggest problem most people have is letting air in from the top and then having to bleed and bleed and bleed to get the air back out.

    If there is air in the system you may need to reposition the caliper so that the bleed screw is pointing stright up to get it all out.
    On a related topic I understand that Speed Bleeder is now selling the sealant they apply to their bleeder screws so that (I presume) it can be applied to the threads on any bleeder screw. That would solve the problem of the air being pulled in through the threads.

    Or you could just swap in Speed Bleeders for the stock bleeder screws.

    -Gary
    ----------------------
    Gary Wasserman
    MOA#38120 DoD#0216 Airheads#12166 BMWRO
    '85 K100 (RIP), '08 R1200R (RIP), '82 R100S (was an RT)

  8. #8
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    I tried unpluging the ABS, nothing. I tried self-bleed with gravity flow alone, nothing. So maybe it's the rear master cylinder or the pads. The front brakes work great. Bike only has 12,ooo miles, but it sat for years.
    Dave
    PS: their is enough rear brake to hold the bike from rolling back on a slight hill, and the rotor is nice and shiney.

  9. #9

    Pads.....hmmmm.....

    Mine had a badly worn pad on one side of the caliper but the other side still had a lot of pad left.....wonder if yours is doing the same thing and somehow limiting the braking power you're getting.....otherwise the m/c is probably the culprit.

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