Brake system locks up after 2-3 min

Discussion in '5th Generation 1998-2001' started by Witch Doctor, Mar 21, 2009.

  1. btay67

    btay67 New Member

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    Nice job sticking with it and figuring out what was the root cause of this problem. :thumbsup: It sounds like slovfr was on track with the "upper" master cylinder (although I'm not sure it was for the same reason) but it's even better to know the "why". Thank you for all your efforts as I am sure this will benefit many others in the future as well....
     
  2. steven113

    steven113 New Member

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    I finally figured it out! I feel so stupid... My VFR has been a work in progress over the last year and has been completely disassembled, when I put the rear foot brake mastercylinder on I thought that the threaded pin was for petal adjustmet and changed it causing the return to the resevior to be blocked(pumping in but not pumping out. |It has to be a specific depth as stated in the service manual.
     
  3. chas4vfr

    chas4vfr New Member

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    Much thanks to the Original Poster for this thread! After rebuilding my brake master I experienced the exact same issue. Having also rebuilt the clutch master and experiencing a clogged relief passage on the clutch side I was completely convinced I had the same issue on the brake side even though I had checked and verified the relief passage was not clogged on the brake side. I felt pretty stupid having used the same logic in reassembly with the "perfect fitting" actuator rod. I am so glad I found this thread though - and now my brakes work perfectly!
     
  4. Witch Doctor

    Witch Doctor New Member

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    Chas, I'm glad this worked for you. Hope the fancy diagram helped. :)

    That's why I like these boards: they're basically virtual shop notes that we can all search later. I can't tell you how many times I've posted the solution to a problem, then come back a year or two later and found my own fix! (Not necessarily with motorcycles!)
     
  5. Lgn001

    Lgn001 Member

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    Hear, hear! Nice write-up, by the way. I completely agree about sharing information. I've always kind of figured it's a good way to save someone else time and money, along with a lot of frustration.

    I have noticed that the more pain I've gone through to learn something has a direct correlation with how well I remember the information, though. :smile:
     
  6. jspringator

    jspringator New Member

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    Thanks WD! I think I have the same issue. I just unscrew the brake lever, right?

    I'm using a master cylinder from a 2000 VFR800 on my 85 Nighthawk 650. I bought the part from a salvage yard, and had someone else install it. The smaller diameter MC make brake application a LOT easier.

    I found this post looking for a master cylinder rebuild kit!
     
  7. ThatGuyChuck

    ThatGuyChuck New Member

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    Laugh, not a chance. I had the exact same problem last year. Unfortunately it didn't lock the brake right away, I was a mile away from home when it happened. Thankfully I had a wrench and was able to bleed the pressure out of the line which opened the caliper. I tried not to use the brakes on the rest of the way home.

    It took me longer than I'd like to admit to figure out what the problem was. Your picture showing correct and incorrect is easy to understand and is invaluable. I only wish I had seen it before I flipped the plunger.
     
  8. Motographer

    Motographer New Member

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    I don't expect to have to rebuild my MC or do much brake maintenance for a while, but I'm definitely keeping this in mind. Thanks for a great write-up!
     
  9. DentoN

    DentoN New Member

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    Witch Doctor OMG MAN! OMG!)))
    Big thanks to you for this thread and this flawless image, which i found in Google, 5 minutes before i was about to call to any motorcycle service to get the job done for me (expensive thing!).
    I have spent 3 weeks after first time a rebuild all my calipers (rear one did not feel good before). And this brake lock-up got my mind totally blown away!!!
    Huge amount of time, i rebuild all calipers 3 (THREE) times! Got all hose and secondary\rear master cylinders off for clean up too!
    Plus, a lot of money for copper washers (all new after each assembly), brake fluid, cleaners... and a lot of other things. Not to count time and my real\private\work life has suffered a lot from this. Total money waste is about... 200$ i think. And it could be 200$ more if i did not find this thread!
    Plus, my last theory was about faulty china short lever (50$ at Ebay, u know)... i used drill to make hole in lever deeper, so it won't push rod then installing. Lol, that was bad idea and it didn't work, because lever is in totally wrong position then installed now. Well will use other, replica of original long lever now...

    And finally, the winner is - !@#$ brake push rod? Are you kidding me))) omg.
    At office atm, gonna do all things right this evening and see how it works.
    Thank you, thanks a lot from Russia! :eagerness:
     
  10. OZ VFR

    OZ VFR Insider

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    I know this is a very old thread, but it came in handy when I got stuck in the middle of nowhere with my brakes locked up.
    Hard to diagnose on the side of the road with only the standard bikes tool kit.
    I also consider my self a good mechanic who pays attention to detail, but this had me stumped.
    Lucky for Internet access and VFRWorld.
    Very easy to install the push rod back to front, and it takes a while for heat to build up and lock up your brakes. 100k's in my case.
    Thought I'd bump this up for people to see.
     
  11. DentoN

    DentoN New Member

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    This thread just saved time and money of another fellow from Russian motoforum.
    Found his thread about locking brakes on CB400SF - showed him this solution. Happinies!
    Thanks Witch Doctor, another bump for really helpful thread, people should know! :D
     
  12. TailwindAndy

    TailwindAndy New Member

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    Witch Doctor, you're a genius man. I had exactly the same problem and it was driving me insane. I had stripped both calipers down, polished those pistons 'till they were like new, brand new Honda seals, new M/C repair kit, brake cleaner and compressed air through both holes, but the sodding brakes were completely hydraulic locked. Turned that little lever the other way round after reading this post and boom......perfect brakes - thanks a lot.
     
  13. squirrelman

    squirrelman Member

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    interesting thread !

    Overfilling the MC can also cause brakes to lock.
     
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