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Brake problem help

Discussion in 'Moto Club' started by OdinIII, Apr 21, 2008.

  1. OdinIII


    Nov 13, 2001
    Gainesville, GA
    I am working to get my 96 CBR back on the road after an extended storage but I'm having trouble with the front brakes. The lever is very stiff and if you ride it for a short time the front brakes start dragging.

    Everyone tells me it is probably the brake hose breaking down internally. It seems to me that if a caliper was sticking the lever would feel normal so this may be the problem.

    Anyone had this problem? What does a stiff lever indicate? It feels like there is pressure in the system that isn't getting relieved.

    I'm scared anything I do to it (bleed, clean caliper pistons) may make the symptoms go away temporarily. I really want to work on the most likely problem.
  2. HollowHead

    HollowHead Firm member

    May 16, 2005
    Where the buffalo roam
    From what you are describing, you need a front master cylinder rebuild kit. It's a fairly easy repair and should fix the problem. The other problem could be sticking pistons in the caliper, but the likelyhood of all of them sticking and causing a drag is slight. HH

  3. paul-s


    Feb 27, 2008
    p'cola fl
    check the temps on all disc's, it might be a caliper, master cyl. or line. did you change the fluid?
  4. OdinIII


    Nov 13, 2001
    Gainesville, GA
    I haven't changed the fluid in several years. I changed it before some track days several years ago and rode it on the street very little since.

    Just to clarify, I rode it to the store several days ago and only noticed the stiff lever until I tried to pull away from the pump. It felt like it had a parking brake on. I didn't have the presence of mind to check the rotor temp. After I got a trailer to the store the front had released and rolled normally.

    Currently the calipers stop and release normally. I can pull the lever 40 to 50 times and can at most get a pad to make a slight rubbing sound with no increased rolling resistance when the lever is released.

    The master cylinder feels smooth except it doesn't have the easy first 1" or so of the pull. It feels like there is already pressure in the system before the lever is pulled.

    A fellow at work says that a brake line can leak between the outer and inner hose and that this can collapse the inner hose and create a restriction.

    Wouldn't a bad master cylinder either have a rough pull or leak down after being pulled?

    Wouldn't a bad caliper not release at all and also not affect the feel of the brake lever?

    Those two questions seem to only leave the brake hose. I was reluctant to think it could be the line until my co-worker explained about the double lined hose and how it could leak internally.

    Does this make sense? I really don't want to wreck because I thought I had it fixed.
  5. PDude


    May 5, 2005
    Take off the calipers and remove the dust boots. Clean all the grunge from the side of the pistons, then work them in and out to make sure they are free.

    Make sure the pads can move freely. Check for excess flashing on the pad edges that may need to filed smooth. Lightly lube the retention pins.

    Remove the master cylinder cap and suck out the old fluid, wipe any dirt out of the cup and fill with fresh fluid ( best if newly opened). Then bleed until the fluid comes out clean. I usually bleed it again after a few days and a few heat cycles to see if any more air will come out.

    A very slight drag may be unavoidable, it will usually knock back in while in operation. Rotors often aren't perfectly flat. If they are clean they should retract enough.

    Hoses do collapse, but not as often as I hear theorized. SS lines are nice to have.

    Fluid is hygroscopic (it absorbs moisture) which causes most of the problems, such as corrosion. Clean fluid is a pet peeve of mine, I change it every year on all my rides.
    I think this is why I have never had to replace a caliper.

    My wife just loves to be my little brake pumper, NOT!